Motivation serves as a pivotal driver for achieving optimal work performance, especially in the realm of local government operations. Through a qualitative multiple-case study design, the researchers analyzed the pivotal connection between employees' performance and overall organizational success. Thirteen (13) participants from the first-class municipalities in the first district of Batangas were selected using purposive sampling techniques. Face-to-face interviews were conducted to get the opinions of the participants and were subsequently subjected to thematic analysis. The findings highlight the strong connection (...) between motivational tools and employee preferences. Despite the local government's emphasis on teamwork and collaboration, employees exhibit a strong preference for incentives, rewards, and acknowledgment. Advocating for the systematic integration of employee feedback into motivational strategy formulation and the necessity of comprehensive evaluations of existing tools. Additionally, it underscores the importance of cultivating an inclusive environment where employees actively participate in discussions about motivational approaches. By embracing the proposed motivational plan that considers both organizational and employee perspectives, this research seeks to cultivate a culture of heightened productivity and performance enhancement within local government units. (shrink)

Successful teamwork doesn't work overnight, what makes teamwork potent is team building. (Plagiarism) According to Abdullah, et. al., (2022) team building training can improve group cohesiveness or the quality of sticking together or unity teamwork more likely to be higher with a significant score difference. This study used mixed methods both qualitative and quantitative data collection, and an analysis method to answer the research method, random sampling is named as such because the data set is chosen via random selection, where (...) every member of the population has an equal probability of being selected (Tao, 2023). The respondents were 100 restaurant employees and 10 managers from the chosen restaurant in Malolos City in Bulacan. The subcategories of team building, including activities, communication, skills, personality, problem-solving, and values, have all received a consensus of strong agreement, with weighted averages falling within the range of 3.26 to 3.44. This level of agreement aligns with the scores for motivation at 3.43 and productivity at 3.38. These values have been calculated by determining the mean, which spans from 3.25 to 4.00. The advantages of team building that is being observed by the managers is to create familiarity and teamwork among the employees, to improve the quality of service and the quality of the food especially the respondents are in the food service sector, development, and training for the employees to achieve the establishments’ goal and lastly rebuilding and build a relationship with one employee to another. However, for the disadvantages, it costs a lot of money to conduct team building in the management. Therefore, the null hypothesis is rejected. Despite the fact that there is a low correlation between teambuilding activities and motivation and employee productivity, there is still a significant relationship between the variables. (shrink)

Public discourse is often caustic and conflict-filled. This trend seems to be particularly evident when the content of such discourse is around moral issues (broadly defined) and when the discourse occurs on social media. Several explanatory mechanisms for such conflict have been explored in recent psychological and social-science literatures. The present work sought to examine a potentially novel explanatory mechanism defined in philosophical literature: Moral Grandstanding. According to philosophical accounts, Moral Grandstanding is the use of moral talk to seek social (...) status. For the present work, we conducted six studies, using two undergraduate samples (Study 1, N = 361; Study 2, N = 356); a sample matched to U.S. norms for age, gender, race, income, Census region (Study 3, N = 1,063); a YouGov sample matched to U.S. demographic norms (Study 4, N = 2,000); and a brief, one-month longitudinal study of Mechanical Turk workers in the U.S. (Study 5, Baseline N = 499, follow-up n = 296), and a large, one-week YouGov sample matched to U.S. demographic norms (Baseline N = 2,519, follow-up n = 1,776). Across studies, we found initial support for the validity of Moral Grandstanding as a construct. Specifically, moral grandstanding motivation was associated with status-seeking personality traits, as well as greater political and moral conflict in daily life. (shrink)

E-money systems have revolutionized global business transactions through digital payment methods. This quantitative correlational study aimed to assess the awareness and acceptance of e-money among individuals in Balayan, Batangas. Employing quota and purposive sampling, 100 participants aged 21 to 70 completed a survey questionnaire. Statistical analysis revealed that consumers were aware of e-money but lacked comprehensive knowledge. They acknowledged the convenience of e-money for online shopping and expense tracking. Age significantly influenced acceptance, while gender did not exhibit a similar effect. (...) Significant differences were observed in awareness and acceptance levels. Recommendations for improving acceptance include administrator-led campaigns, business incentives, consumer education, financial institution partnerships, and integration into student curricula. The study underscores the need for targeted strategies to translate e-money knowledge into practical use. Future research should explore adoption trends over time, barriers, and the impact of regulations on e-money utilization. (shrink)

Socioeconomic status refers to the family's social and economic standing in society. It is measured by combining an individual or group's economic and social position, which is often based on income, education, and occupation. It significantly affects academic performance and even one's health status. The pandemic changed the educational system, causing a huge transition from traditional learning methods to online learning. This shift resulted in confusion, burden, and difficulty among students from different walks of life. This study was conducted to (...) determine the academic stress on online learning among nursing students in relation to their economic status and their ability to access technology. The study utilized a quantitative-correlational method aided by a standard questionnaire. Two hundred thirty-six University of Bohol nursing students enrolled in the second semester of SY 2021–2022 were included in the study by random selection. Data revealed a significant correlation between economic status and the level of stress related to academic expectations and a significant correlation between economic status and access to technology after being subjected to the Spearman rho test of correlation. However, no significant correlation was found between access to technology and the respondents' level of academic stress. (shrink)

The Repugnant Conclusion served an important purpose in catalyzing and inspiring the pioneering stage of population ethics research. We believe, however, that the Repugnant Conclusion now receives too much focus. Avoiding the Repugnant Conclusion should no longer be the central goal driving population ethics research, despite its importance to the fundamental accomplishments of the existing literature.

Public health care interventions—regarding vaccination, obesity, and HIV, for example—standardly take the form of information dissemination across a community. But information networks can vary importantly between different ethnic communities, as can levels of trust in information from different sources. We use data from the Greater Pittsburgh Random Household Health Survey to construct models of information networks for White and Black communities--models which reflect the degree of information contact between individuals, with degrees of trust in information from various sources correlated with (...) positions in that social network. With simple assumptions regarding belief change and social reinforcement, we use those modeled networks to build dynamic agent-based models of how information can be expected to flow and how beliefs can be expected to change across each community. With contrasting information from governmental and religious sources, the results show importantly different dynamic patterns of belief polarization within the two communities. (shrink)

Risk Management Strategies and Investment Behaviors are considered important factors in the investing activities of the retail investors. This study seeks to determine the relationship between Risk Management Strategies and Investment Behavior of Generation Z retail investors. The study is a correlational research and purposive sampling was used to select the respondents for this study. Cochran’s formula was utilized to determine the total sample size or total number of respondents. Spearman’s Rank-Order Correlation was employed to assess the significant relationship of (...) Risk Management Strategies and Investment Behaviors. Based on the results, it showed that risk management strategies have a significant relationship with one or more of the investment behaviors. Risk avoidance has a significant relationship with confirmation bias. Risk reduction has a significant relationship with all of the investment behaviors such as overconfidence, loss-aversion, recency bias, and confirmation bias. Risk transfer shows a significant relationship with only loss-aversion and confirmation bias. And lastly, risk acceptance also has a significant relationship with all of the investment behaviors. This study recommends exploring other types of behavioral biases under cognitive bias and emotional bias to determine their correlation with risk management strategies. Also, broadening the sample size, demographic scope, and geographic scope of the study can improve the generalizability of the study and provide a more comprehensive understanding of the relationship between investment behavior and risk management strategies. The researchers also recommend to utilize interviews and focus group discussions to gain an in-depth understanding of the underlying values and attitudes concerning investment behavior. (shrink)

Academic institutions migrated to modular teaching-learning amid the COVID-19 pandemic. To ensure the quality of the pedagogical innovations employed, the study determined the students’ evaluation of the faculty prepared instructional modules for the courses they enrolled in during the first and second semesters of Academic Year 2020-2021. Employing a descriptive-correlational research design, the study was participated by 644 students from three colleges who were then available during the data gathering. Data gathered through online surveys were then analyzed using descriptive statistics (...) and Spearman's rank correlation coefficient utilizing jamovi software. Results revealed that the faculty-prepared instructional modules were acceptable and satisfactory to the students. Besides, the students' evaluation of the instructional modules was positively related to their level of satisfaction. Still, the students recommended that a review of the modules be done before sending the modules; a more extended time allotment is considered, and sufficient concrete examples are given in the modules. With this, the faculty concerned are encouraged to review the phases involved in the design, development, and distribution of the instructional modules to make them highly acceptable and very satisfactory to the students while maintaining the quality of both the content and aesthetics of the learning materials. Considering the study’s limitations, further endeavors may be carried out to validate this pedagogical innovation. (shrink)

Functional diversity holds the promise of understanding ecosystems in ways unattainable by taxonomic diversity studies. Underlying this promise is the intuition that investigating the diversity of what organisms actually do—i.e. their functional traits—within ecosystems will generate more reliable insights into the ways these ecosystems behave, compared to considering only species diversity. But this promise also rests on several conceptual and methodological—i.e. epistemic—assumptions that cut across various theories and domains of ecology. These assumptions should be clearly addressed, notably for the sake (...) of an effective comparison and integration across domains, and for assessing whether or not to use functional diversity approaches for developing ecological management strategies. The objective of this contribution is to identify and critically analyze the most salient of these assumptions. To this aim, we provide an “epistemic roadmap” that pinpoints these assumptions along a set of historical, conceptual, empirical, theoretical, and normative dimensions. (shrink)

This study investigated the effectiveness of utilizing induced magnetism on the seed germination of radish (Raphanussativus) in terms of growth rate, growth speed, shoot growth, and overall development. This study utilized two groups that consisted of an experimental group where induced magnetism was present one control group where there was an absence of induced magnetism in the seed germination of Radish (Raphanus sativus). Moreover, this study aimed to determine the significant difference between the two in terms growth rate, growth speed, (...) shoot growth, and overall development. Both groups had the same amount of radish (Raphanus sativus) seeds planted in a rectangular wooden container with the same amount of measurement and soil content. This study used an experimental research design by utilizing the functions of an Electromagnetic Induction Device (EID) comprised of a 12v motor battery, light bulb, coiled wire, and switch. The EID was turned on for 10 minutes every day where the electric volts generated by the 12v motor battery were transported through the coiled wire and distributed to the metallic iron screen surrounding the area of the experimental group. The data gathered during the 12-day observation of the growth of radish (Raphanus sativus) were tabulated, analyzed, and evaluated using mean tests, standard deviation, and T-test. Based on the result and analyses of the gathered data, it was found that the experimental group, the one with the presence of induced magnetism, surpassed the control group in terms of growth speed, shoot growth, and overall seed development. However, it was also revealed that in terms of growth rate, there is no significant difference between the control group and experimental group. Therefore, the utilization of Induced Magnetism on the seed germination of radish (Raphanus sativus) is effective in terms of growth speed, shoot growth, and overall development. (shrink)

It is often argued that the indispensability of continuum models comes from their empirical adequacy despite their decoupling from the microscopic details of the modelled physical system. There is thus a commonly held misconception that temperature varying across a region of space or time can always be accurately represented as a continuous function. We discuss three inter-related cases of temperature modelling — in phase transitions, thermal boundary resistance and slip flows — and show that the continuum view is fallacious on (...) the ground that the microscopic details of a physical system are not necessarily decoupled from continuum models. We show how temperature discontinuities are present in both data (experiments and simulations) and phenomena (theory and models) and how discontinuum models of temperature variation may have greater empirical adequacy and explanatory power. The conclusions of our paper are: a) continuum idealisations are not indispensable to modelling physical phenomena and both continuous and discontinuous representations of phenomena work depending on the context; b) temperature is not necessarily a continuously defined function in our best scientific representations of the world; and c) that its continuity, where applicable, is a contingent matter. We also raise a question as to whether discontinuous representations should be considered truly de-idealised descriptions of physical phenomena. (shrink)

(Longer version - work in progress) Various accounts of distinctively mathematical explanations (DMEs) of complex systems have been proposed recently which bypass the contingent causal laws and appeal primarily to mathematical necessities constraining the system. These necessities are considered to be modally exalted in that they obtain with a greater necessity than the ordinary laws of nature (Lange 2016). This paper focuses on DMEs of the number of equilibrium positions of n-tuple pendulum systems and considers several different DMEs of these (...) systems which bypass causal features. It then argues that there is a tension between the modal strength of these DMEs and their epistemic hooking, and we are forced to choose between (a) a purported DME with greater modal strength and wider applicability but poor epistemic hooking, or (b) a narrowly applicable DME with lesser modal strength but with the right kind of epistemic hooking. It also aims to show why some kind of DMEs may be unappealing for working scientists despite their strong modality, and why some DMEs fail to be modally robust because of making ill-informed assumptions about their target systems. The broader goal is to show why such tensions weaken the case for DMEs for pendulum systems in general. (shrink)

Different sort of people are interested in personal identity. Philosophers frequently ask what it takes to remain oneself. Caregivers imagine their patients’ experience. But both philosophers and caregivers think from the armchair: they can only make assumptions about what it would be like to wake up with massive bodily changes. Patients with a locked-in syndrome (LIS) suffer a full body paralysis without cognitive impairment. They can tell us what it is like. Forty-four chronic LIS patients and 20 age-matched healthy medical (...) professionals answered a 15-items questionnaire targeting: (A) global evaluation of identity, (B) body representation and (C) experienced meaning in life. In patients, selfreported identity was correlated with B and C. Patients differed with controls in C. These results suggest that the paralyzed body remains a strong component of patients’ experienced identity, that patients can adjust to objectives changes perceived as meaningful and that caregivers fail in predicting patients’ experience. (shrink)

With an increased emphasis on upstream activity and Defence Engagement, it has become increasingly more important for the UK Ministry of Defence (MOD) and government to understand the relationship between conflict and regional instability. As part of this process, the Historical and Operational Data Analysis Team (HODA) in Defence Science and Technology Laboratory (Dstl) was tasked to look at factors that influenced the regional spread of internal conflicts to help aid the decision making of government. Conflict contagion is the process (...) by which a conflict in one state (State A) influences the outbreak of conflict in another state (State B). The aim of looking at these factors was to produce a tool to assist in the cost/benefit analysis of intervening in future conflicts. The task was carried out by quantitatively studying a selection of contagion and non-contagion case studies over a set of 14 numerical variables that covered structural, political, socioeconomic and cultural factors of both States A and B. All case studies took place after the end of the Cold War. The dataset used contained both binary and continuous data. A range of statistical techniques were used including correlation, regression and principal component analyses along with graphical analytical methods. Unfortunately creating a tool to predict contagion has proven difficult and so the scope of the study was changed-as no statistically relevant link was found. However, it was shown that some links do exists between the variables and the existence of contagion, and it also appears it is a combination of variables which has an effect on the likelihood of contagion. Conflict contagion is a rare event and was only recorded in less than 1% of cases present in the dataset. Of the variables analysed, the most significant factor was the number of refugees present in State B who originated in State A for the year before the case study. It is recommended that further work be conducted. It is possible that a more detailed investigation, using a broader range of techniques and/or a wider selection of variables might be successful in assessing the likelihood of conflict contagion. (shrink)

Ernst Mach’s definition of the relationship between thoughts and facts is well known, but the question of how Mach conceived of their actual relationship has received much less attention. This paper aims to address this gap in light of Mary B. Hesse’s view of a postempiricist approach to natural science. As this paper will show, this view is characterized by a constructivist conception of the relationship between theory and facts that seems to be consistent with Mach’s observations on scientific (...) knowledge. The paper first explores Hesse’s account of postempiricism and her project of a new epistemology. It then considers Ernst Mach’s conception of facts as the middle term of a triad of concepts that includes thoughts and elements as extreme terms. Finally, the paper will offer concluding remarks on Mach’s contribution to the debate on scientific realism and his attempt to redefine the notions of correspondence and objectivity in science. (shrink)

We examine how Frege’s contrast between identity judgments of the forms “a=a” vs. “a=b” would fare in the special case where ‘a’ and ‘b’ are complex mental representations, and ‘a’ stands for an introspected ‘I’-thought. We first argue that the Fregean treatment of I-thoughts entails that they are what we call “one-shot thoughts”: they can only be thought once. This has the surprising consequence that no instance of the “a=a” form of judgment in this specific case comes out true, let (...) alone a priori true. This further reinforces Glezakos’s objections against the set-up of Frege’s puzzle, while also raising what we think is an acute problem for Fregeans, insofar as I-thought (and indexical thinking more generally), understood in their way, turns out to be incompatible with some basic features of rationality. (shrink)

According to the mental model theory, causes and enablers differ in meaning, and therefore in their logical consequences (Goldvarg & Johnson-Laird, 2001). They are consistent with different possibilities. Recent psychological studies have argued to the contrary, and suggested that linguistic cues guide this distinction (Kuhnmünch & Beller, 2005). The issue is important because neither British nor American law recognizes this distinction (e.g., Roberts & Zuckerman, 2004). Yet, in our view, it is central to human conceptions of causality. Hence, in two (...) experiments, we examined our participants’ ability to distinguish between causes and enablers in scenarios describing the actions of two agents and a subsequent outcome, e.g.: ‘Mary threw a lighted cigarette into a bush. Just as the cigarette was going out, Laura deliberately threw petrol on it. The resulting fire burnt down her neighbor’s house.’ Here Mary enabled the fire to occur, whereas Laura caused the fire to occur. (shrink)

Impulse and momentum are basic concepts of mechanics introduced in the K to 12 curricula. Despite its basic concepts, students still have difficulties understanding the topic, especially when they are out of school due to the pandemic. After reopening the gates for face–to–face classes in the Philippines, the researchers found a significant reason to conduct a lesson study to improve teaching strategies on the topic. Lesson study is a development process wherein teachers work collaboratively to improve teachers teaching capacity. This (...) study was conducted at Plaridel National High School with 23 participants from Grade 9 Newton (Set A and B). The research was conducted in two cycles using a four – phase lesson study. The research lesson was implemented using a 4A Model lesson plan and the results were taken from the analysis of the lesson study observation sheets, along with the class proficiency level. The researchers used the following strategies to improve teaching, namely; (1) showing mastery of subject matter, (2) reviewing basic mathematical operations, (3) contextualizing the lesson, (4) allowing students to answer questions in mother tongue, (5) using collaborative activities, (6) giving rewards, and (7) applying proper time management. However, the findings still showed that both sets of students achieved beginning proficiency level. Despite the implementation of these strategies, the students still lack basic knowledge of the topic and mathematical operations, and they struggle to understand it. Thus, it is recommended to plan the lesson effectively, utilize other research instruments, and collect feedback from the students. (shrink)

In this paper, I argue for a new solution to Mary’s puzzle in Jackson’s famous knowledge argument. We are told that imprisoned Mary knows all facts or truths about color and color vision. On her release, she learns something new according to B-type of materialism and according to property dualism. I argue that this cognitive improvement can only be accounted for in terms of what Schellenberg has recently called “capacitism,” namely the claim that that experience is constitutively a (...) matter of discriminating and singling out particulars by employing perceptual capacities. Of course, I am not claiming that knowing the phenomenal character is simply the possession of abilities, let alone that the phenomenal character is a sort of know-how. That is why my claim is not affiliated with Lewis and Nemirow's ability hypothesis position. I take for granted here a sort of property-representationalism, according to which the phenomenal character of experience supervenes on the cluster of properties that the respective experiences represent. On her release, Mary acquires those perceptual abilities on the basis of which she learns to discriminate all shades of color. And after applying her old physical concept RED to the shade of red, she comes to know what it is like to experience red (propositional knowledge). (shrink)

This paper is largely exegetical/interpretive. My goal is to demonstrate that some criticisms that have been leveled against the program Gareth Evans constructs in The Varieties of Reference (Evans 1980, henceforth VR) misfire because they are based on misunderstandings of Evans’ position. First I will be discussing three criticisms raised by Tyler Burge (Burge, 2010). The first has to do with Evans’ arguments to the effect that a causal connection between a belief and an object is insufficient for that belief (...) to be about that object. A key part of Evans’ argument is to carefully distinguish considerations relevant to the semantics of language from considerations relevant to the semantics (so to speak) of thought or belief (to make the subsequent discussion easier, I will henceforth use ‘thought’ as a blanket term for the relevant mental states, including belief). I will argue that Burge’s criticisms depend on largely not taking account of Evans’ distinctions. Second, Burge criticizes Evans’ account of ‘informational content’ taking it to be inconsistent. I will show that the inconsistency Burge finds depends entirely on a misreading of the doctrine. Finally, Burge takes Evans to task for a perceived over-intellectualization in a key aspect of his doctrine. Burge incorrectly reads Evans as requiring that the subject holding a belief be engaged in certain overly intellectual endeavors, when in fact Evans is only attributing these endeavors to theorists of such a subject. Next, I turn to two criticisms leveled by John Campbell (Campbell, 1999). I will argue that Campbell’s criticisms are based on misunderstandings – though they do hit at deeper elements of Evans’ doctrine. First, Campbell reads Evans’ account of demonstrative thought as requiring that the subject’s information link to an object allows her to directly locate that object in space. Campbell constructs a case in which one tomato (a) is, because of an angled mirror, incorrectly seen as being at a location that happens to be occupied by an identical tomato (b). Campbell claims that Evans’ doctrines require us to conclude that the subject cannot have a demonstrative thought about the seen tomato (a), though it seems intuitively that such a subject would be able to have a demonstrative thought about that tomato, despite its location is inaccurately seen. I show that Evans’ position in fact allows that the subject can have a demonstrative thought about the causal-source tomato in this case because his account does not require that the location of demonstratively identified objects be immediately accurately assessed. What is crucial is that the subject have the ability to accurately discover the location. Second, Campbell criticizes Evans’ notion of a fundamental level of thought. I show that this criticism hinges on view of the nature and role of the fundamental level of thought that mischaracterizes Evans’ treatment of the notion. (shrink)

On being released from her black-and-white room into a colorful world it would seem Mary learns something new (the Knowledge Argument). On being released from his B-theory room into an A-theory world it would seem Mark learns something new (the Temporal Knowledge Argument). These thought experiments are parallel to each other and can inform each other.

Jackson (1982) introduced the Knowledge Argument to elucidate the phenomenal, interior aspects of experience. In 1908 McTaggart defined two series that characterize one dimension of time, the A-series and the B-series. The A-series is usually thought to be phenomenal Farr (2019), SEP (2018). Thus there is the possibility of giving a Knowledge Argument for time. One (informal) statement of the classical Knowledge Argument might be “Mary knows all the facts about color qualia but lives in a black-and-white room. Upon (...) being released into a colorful world, it would seem she learns something new.” The analogous Knowledge Argument for Time (KAT) would be “Nathan knows all the facts about time but lives in a B-series room. Upon being released into a world with both an A-series and a B-series it would seem he learns something new.” I give variations of the KAT based on various distinctions. I don’t give any particular proposed solutions to the Knowledge Arguments for Time. Rather, the point is to state the Arguments (or indicate how they may be stated). It may be hoped that these will help clarify some issues in the philosophy of time and lead to a cross-fertilization between the philosophy of time and the philosophy of mind. (shrink)

This paper develops a semantic solution to the puzzle of Free Choice permission. The paper begins with a battery of impossibility results showing that Free Choice is in tension with a variety of classical principles, including Disjunction Introduction and the Law of Excluded Middle. Most interestingly, Free Choice appears incompatible with a principle concerning the behavior of Free Choice under negation, Double Prohibition, which says that Mary can’t have soup or salad implies Mary can’t have soup and (...) class='Hi'>Mary can’t have salad. Alonso-Ovalle 2006 and others have appealed to Double Prohibition to motivate pragmatic accounts of Free Choice. Aher 2012, Aloni 2018, and others have developed semantic accounts of Free Choice that also explain Double Prohibition. -/- This paper offers a new semantic analysis of Free Choice designed to handle the full range of impossibility results involved in Free Choice. The paper develops the hypothesis that Free Choice is a homogeneity effect. The claim possibly A or B is defined only when A and B are homogenous with respect to their modal status, either both possible or both impossible. Paired with a notion of entailment that is sensitive to definedness conditions, this theory validates Free Choice while retaining a wide variety of classical principles except for the transitivity of entailment. The homogeneity hypothesis is implemented in two different ways, homogeneous alternative semantics and homogeneous dynamic semantics, with interestingly different consequences. (shrink)

Autonomous and automatic weapons would be fire and forget: you activate them, and they decide who, when and how to kill; or they kill at a later time a target you’ve selected earlier. Some argue that this sort of killing is always wrong. If killing is to be done, it should be done only under direct human control. (E.g., Mary Ellen O’Connell, Peter Asaro, Christof Heyns.) I argue that there are surprisingly many kinds of situation where this is false (...) and where the use of Automated Weapons Systems would in fact be morally required. These include cases where a) once one has activated a weapon expected then to behave lethally, it would be appropriate to let it continue because this is part of a plan whose goodness one was best positioned to evaluate before activating the weapon; b) one expects better long-term consequences from allowing it to continue; c) allowing it to continue would express a decision you made to be resolute, a decision that could not have advantaged you had it not been true that you would carry through with it; d) the weapon is mechanically not recallable, so that, to not allow it to carry through, you would have had to refrain from activating it in the first place, something you expected would have disastrous consequences; e) you must deputize necessary killings to autonomous machines in order to protect yourself from guilt you shouldn’t have to bear; f) it would be morally better for the burden of responsibility for the killing to be shared among several agents, and the agents deputizing killing to machines can do this, especially where it’s not predictable which machine will be successful; g) a killing would be morally better done with elements of randomness and lack of deliberation, and a (relatively stupid) machine could do this where a person could not; h) the machine would be acting as a Doomsday Device, so that it could not have had its hoped for deterrent effect had you not ensured that you would be unable to recall it if enemy action activated it; i) letting it carry through is a necessary part of its own learning process, and you expect that this learning will have salutary effects later on; j) human intervention in the machine’s operation would disastrously impair its precision, or its speed and efficiency; k) using non-automated methods would require human resources you just don’t have in a task that nevertheless must be done (e.g., using land-mines to protect remote installations); l) the weapon has such horrible and indiscriminate power that it is doubtful whether it could be actually used in ways compatible with International Humanitarian Law and the Laws of War, which require that weapons be used only in ways respecting distinctness, necessity and proportionality, but its threat of use could respect these principles in affording deterrence provided human error cannot lead to their accidental deployment, this requiring that they be controlled by carefully designed autonomous and automatic systems. I then consider objections based on conceptions of human dignity and find that very often dignity too is best served by autonomous machine killing. Examples include saving your village by activating a robot to kill invading enemies who would inflict great indignity on your village, using a suicide robot to save yourself from a less dignified death at enemy hands, using a robotic drone to kill someone otherwise not accessible in order to restore dignity to someone this person killed and to his family, and using a robot to kill someone who needs killing, but the killing of whom by a human executioner would soil the executioner’s dignity. I conclude that what matters in rightful killing isn’t necessarily that it be under the direct control of a human, but that it be under the control of morality; and that could sometimes require use of an autonomous or automated device. (This paper was formerly called "Fire and Forget: A Defense of the Use of Autonomous Weapons in War" on Philpapers; the current title is the title of the published version.). (shrink)

A collection of essays, mostly original, on the actual and possible positions on free will available to Buddhist philosophers, by Christopher Gowans, Rick Repetti, Jay Garfield, Owen Flanagan, Charles Goodman, Galen Strawson, Susan Blackmore, Martin T. Adam, Christian Coseru, Marie Friquegnon, Mark Siderits, Ben Abelson, B. Alan Wallace, Peter Harvey, Emily McRae, and Karin Meyers, and a Foreword by Daniel Cozort.

That i) there is a somehow determined chronology of Plato’s dialogues among all the chronologies of the last century and ii) this theory is subject to many objections, are points this article intends to discuss. Almost all the main suggested chronologies of the last century agree that Parmenides and Theaetetus should be located after dialogues like Meno, Phaedo and Republic and before Sophist, Politicus, Timaeus, Laws and Philebus. The eight objections we brought against this arrangement claim that to place the (...) dialogues like Meno, Phaedo and Republic both immediately after the early ones and before Parmenides and Theaetetus is epistemologically and ontologically problematic. -/- Key Words: Plato; chronology; knowledge; being; Parmenides -/- Introduction While the ancient philosophers, doxographers and commentators from Aristotle onward considered, more or less, the question of the date and arrangement of the dialogues (cf. Irwin 2008, 77 n. 69), they would not observe a firm necessity to consider the progress of Plato’s theories in dialogues, maybe because they did not think of any essential shift in there. We might be able to say, nevertheless, that the most prominent feature of the ancient attitude to Plato was its peculiar attention to the Republic and the Timaeus as the most mature works in his philosophy and also the consideration of Laws as a later work. This tendency can be discovered from the general viewpoint of the first chronologies of the early 19th century after starting to deal with the issue. That Schleiermacher observed Republic as the culmination of Plato’s philosophy and as one of the latest dialogues besides Laws and Timaeus could reflex the implicit chronology of the tradition in the first mirrors it found. Another tendency in Schleiermacher is taking the triology of Theaetetus, Sophist and Politicus as relatively early. From the last quarter of 19th century onward, stylometry helped scholars to establish a new framework to constructa new arrangement between the dialogues. Based on stylistic as well as literary findings, Campbell (1867, xxxff.) argued for the closeness of the style of Sophist and Politicus with Timaeus, Critias, Philebus and Lawsthat, especially because of the certain evidence about this last dialogue’s lateness, led to the consideration of all as late dialogues. Almost every other stylistic effort after Campbell approved the similarities between Sophist and Politicus with Timaeus, Critias, Philebus and Laws. The result of all such investigations led to a new chronology that, despite some differences, has a fixed structure in all its appearances. 1. The Standard Chronology of the Dialogues The chronologies that are now commonly accepted are mostly based on the arrangement of dialogues to three groups corresponding to three periods of Plato’s life, which became predominant after applying stylistic features in assessing the similarities between dialogues. The fact that all the stylometric considerations reached to the similar results about the date of dialogues while they were assessing different stylistic aspects helped the new chronology become prevailing not only among stylistic chronologies but also between those like Fine, Kahn and Vlastos who were inclined more to the content-based arrangements. Even this latter group could not neglect the apparently certain results of using the method of stylometry. This was the main reason, I think, that made what they called content-based chronology be under the domination of stylometry much more than they could expect. The division of the dialogues into three separate groups became something that most of the scholars took for granted so far as Kahn thinks this division 'can be regarded as a fixed point of departure in any speculation about the chronology of the dialogues' (1996, 44). Thereafter, all the chronologists are accustomed to divide the dialogues to three groups of early, middle and late corresponding to the three stages of Plato’s life. Nevertheless, some of them tried to make subdivisions among each group and introduce some of the dialogues as transitional between different periods and thus reached to a fourfold classification of the dialogues. Although theycould never achieve to a consensus about the place of some dialogues, about which we will discuss soon, the whole spirit of theirchronological arrangements is the same and thus compelling enough for us to unify all of them with the label of 'Standard Chronology of Dialogues' (SCD). We brought together some of the most famous chronologies in the table below to make a comparison easier and to show how all are approximately of the same opinion about the place of some dialogues. The following points must be noted about this table: 1. I divided the dialogues to eight groups of early, late early, transitional, early middle, late middle, post-middle, early late, and late. Although none of the chronologists applies this classification, it can be helpful to compare them. In this table, for example, if one of the chronologist’s beholds one of the dialogues as later than all the dialogues of middle group, it is considered here as late middle. Otherwise, if it is emphasized that it is after all of them, it is considered as post-middle. The same is true about the dialogues of the late group in which I regarded the first dialogues of that period as early late only in those who explicitly considered some dialogues as earlier than other ones in the late group. Though, therefore, some of the dialogues might have not been considered as forming a distinct class, they are distinguished here. A. SCD’s Early and Transitional Dialogues When we move from stylometric to content-based chronologies, the homogeneity between the dialogues of each group is more understandable. Guthrie (1975, v. 4, 50) distinguishes three groups, the first of them includes Apology, Crito, Laches, Lysis, Charmides, Euthyphro, Hippias Minor, Hippias Major, Protagoras, Gorgiasand Ion. In addition to Meno, Phaedo and Euthydems, his first group does not include Cratylus and Menexenus. Unlike Guthrie, almost all the other content-based chronologiesof our study desire to distinguish two categories inside the first group of which the latter must be considered as the transitional group leading to the dialogues of the middle period. Kahn distinguishes four groups of dialogues and arranges two of them before middle period dialogues. The first group including Apology, Crito, Ion, Hippias Minor, Gorgiasand Menexenus he calls 'early' or 'presystematic' dialogues (1998, 124). The second group he calls the 'threshold', 'pre-middle' or 'Socratic' dialogues including seven: Laches, Charmides, Lysis, Euthyphro, Protagoras, Euthydemus and Meno. Based on Vlastos’ arrangement we must distinguish Euthydemus, Hippias Major, Lysis, Menexenus and Meno as 'transitional' dialogues from the 'elenctic' dialogues that are the other dialogues of Kahn’smentioned first two groups plus the first book of theRepublic. Fine also distinguishes 'transitional' dialogues from early or 'Socratic' dialogues,but her transitional dialogues are Gorgias, Meno, Hippias Major, Euthydemus and Cratylus of which she thinks the last two dialogues are 'controversial' (2003, 1). Her Socratic dialogues are all the remaining dialogues of Kahn’s first two groups. In spite of all the differences between the mentioned chronologies, it can be seen that all of them are inclined to arrange the early dialogues in a way that: i) Besides the dialogues that are considered as late, it never includes Republic II-X, Theaetetus, Phaedrus and Parmenides. ii) It intends to consider the dialogues like Euthydemus and Hippias Majorthat look more critical as later among the earlier dialogues or as transitional group. iii) Those who do not consider Meno as a middle period dialogue place it in their second or transitional group. iv) None of the content-based chronologies considers Phaedo and Symposium as early. Stylometric chronologies also intend to put them either as last dialogues among their early ones or as middle. B. SCD’s Middle Period Dialogues Campbell listed Republic, Phaedrus, Parmenides and Theaetetus as his second group of dialogues, an idea thatwas accepted by Brandwood. Ledger’smiddle period dialogueshad Euthydemus, Symposium and Cratylus in addition to the dialogues that Campbell and Brandwood had mentioned as middle. Among content-based chronologies, Guthrie’s list of middle period dialogues did not include Parmenides but some dialogues which had been considered as early in stylometric ones: Meno, Phaedo, Republic, Symposium, Phaedrus, Euthydemus, Menexenus and Cratylus. In sofar as I know, Euthydemus and Menexenus have not been considered as middle by other content-based chronologists and Guthrie is an exception among them. That Phaedo, Phaedrus, Symposium and Republic were middle period dialogues almost all the philosophical chronologists like Kahn, Fine, Vlastos (except Rep.I), Irwin andKraut came along. The dialogues they do not string along about are Meno, Cratylus, Parmenides and Theaetetus. Those like Guthrie, Kraut and Irwin who did not consider Meno as early presumably posit it among middles. The same can be said about Cratylus in the suggested chronologies of Guthrie, Kahn, Vlastos and Kraut. Nonetheless, it is different in case of Parmenides and Theaetetus. Whereas all the mentioned stylometric chronologists like Campbell, Brandwood and Ledger set them among middle period dialogues,the philosophical chronologists, it might seem at first, did not arrive at a consensus about them. While Guthrie and Fine put them as the first dialogues of the late group, Vlastos and Kraut set them as the latest of the middle group, as well as Kahn who puts them as post-middle and amongst the late period dialogues. Regardless the way they classify their groups, their disagreement does not affect the arrangement of the dialogues: they all posit Parmenides and Theaetetus after the series of Meno, Phaedo, Phaedrus, Symposium and Republic and before Sophist, Politicus, Timaeus, Philebus and Laws. To sum up SCD’s arrangement of the middle period dialogues we can add: v) Republic and Phaedrus have been considered by all the mentioned chronologists as dialogues of the middle period. vi) All the philosophical chronologies have reached a consensus about setting Phaedo and Symposium alongside with Republic and Phaedrus as middle. vii) While Stylometric alongside some philosophic chronologists arrange Parmenides and Theaetetus among their middle period dialogues and mostly as the latest among them, other philosophical chronologists put them as the early among the late dialogues. We can conclude then that SCD intends to locate these two dialogues at the boundary between the middle and late period dialogues. -/- . (shrink)

Intuitions play an important role in contemporary philosophy. It is common for theories in epistemology, morality, semantics and metaphysics to be rejected because they are inconsistent with a widely and firmly held intuition. Our goal in this paper is to explore the role of epistemic intuitions in epistemology from a naturalistic perspective. Here is the question we take to be central: (Q) Ought we to trust our epistemic intuitions as evidence in support of our epistemological theories? We will understand this (...) question as employing an epistemic ‘ought’ – insofar as we aim at developing a correct epistemological theory, ought we to trust our epistemic intuitions as evidence for or against our epistemological theories? As it stands, (Q) needs further clarification. Whether something is trustworthy is relative to what (a) what it is and (b) what we’re asking it to do. Sam might trust Marie but not George to care for his children, while he might trust both to care for his pet fish. So in order to address (Q), we first need to explore two questions: What are epistemic intuitions? And what sort of epistemological theories do we want? We will take up each of these questions in the following sections. (shrink)

Time passes iff: P and then Q, for any tensed P and Q. Mary sits; and then she stands. The view—dynamic succession—accommodates the intuition that time passes when events change their A-characteristics: my next birthday is 11 months future and then 10 months future and so on. The view implies an intimate connection between passage, persistence, and change. Persistence and change both presuppose passage. The view charts a path between A-theories (invoking past, present, future) and B-theories (invoking succession). A-theories (...) of passage fail to uncover what makes the passage process go (i.e., succession). B-theories negate tense and therefore mistakenly treat succession as a static relation. Genuine succession makes it so that what comes after replaces what came before. (shrink)

This paper is a new defense of type-B materialism against Jackson’s knowledge argument (1982) inspired by the Kantian main opposition between concepts and sensible intuitions. Like all materialists of type B, I argue that on her release from her black-and-white room, Mary makes cognitive progress. However, contrary to the so-called phenomenal concept strategy (henceforth PCS), I do not think that such progress can be accounted for in terms of the acquisition of new concepts. I also reject Tye’s recent account (...) of Mary’s cognitive progress as the acquisition of a “thing-knowledge.” What is crucial is not the Russellian opposition between knowing things and knowing truths but rather the Kantian opposition between conceptual and nonconceptual representations of the same thing (property). Mary’s phenomenal knowledge is here accounted for as the result of the cooperation of her newly acquired nonconceptual representation of the same phenomenal redness (the same thing) she had a conceptual representation before. As that new nonconceptual representation carries information about the same physical property she already represented but is now coded in analog rather than in digital form (Dretske, 1981), that nonconceptual representation can be accounted for in physical terms as Chalmers’s Master argument requires. Nevertheless, that representation can account for Mary’s cognitive progress since it carries information coded in analog form, something that the imprisoned she could never possess. (shrink)

Predication is a lingual relation. We have this relation when a term is said (λέγεται) of another term. This simple definition, however, is not Aristotle’s own definition. In fact, he does not define predication but attaches his almost in a new field used word κατηγορεῖσθαι to λέγεται. In a predication, something is said of another thing, or, more simply, we have ‘something of something’ (ἓν καθ᾿ ἑνὸς). (PsA. , A, 22, 83b17-18) Therefore, a relation in which two terms are posited (...) to each other in a way that one is said (predicated) of the other is a predication. The term of which the other term is said is called a subject (ὑποκειμένον) and the other, which is said about the subject, is called the predicate. Thus, in a predication the predicate is predicated of the subject; given that being predicated is almost as the same as being said. The relation between being said and being predicated is so close that ‘if something is said of a subject both its name and its definition are necessarily predicated of the subject.’ (Cat., 5, 2a19-26) This, however, is true only about the second genera and not the accidents. a) Nature of relation in predication What is Aristotle’s theory about the nature of the relation in a predication? How does he fundamentally understand this relation? Phil Corkum distinguishes between predication logic and traditional term logic and argues that the relation between subject and predicate in Aristotle is of the latter kind. While in predicate logic, subjects and predicates have distinct roles, they have the same role in traditional term logic. In predication logic, subjects refer, but predicates characterize. Thereupon, a sentence expresses a truth if the object to which the subject refers is correctly characterized by the predicate. In traditional term logic, both subjects and predicates refer and a sentences expresses a truth if both name one and the same thing. He concludes that Aristotle ‘problematically conflates prediction and identity claims’ because while he thinks both subjects and predicates refer, he would deny that a sentence is true just in case the subject and the predicate name one and the same thing. Based on this, Corkum believes that Aristotle’s core semantic is not identity but the weaker relation of constitution, which is a mereological interpretation: ‘All men are mortal’ is true just in case the mereological sum of humans is part of the mereological sum of mortals. b) Aristotle’s theory of predication: one or two theories? Frank Lewis finds an inconsistent gap between the theory of predication in the Categories and that in the later books of the Metaphysics VII, 6. So too Joan Kung, Terry Irwin, Daniel Graham. c) Distinction of ‘being said of’ and ‘being in’ Owen enumerates the texts in which Aristotle’s distinction between ‘being said of’ and ‘being in’ is asserted: OI. 11b38-12a17; To., 127b1-4; Cat. 1a20-b9; 2a11-14; 2a27-b6; 2b15-17; 3a7-32; 9b22-24 d) Predication in Aristotle and the standard ‘S is P’ Marie De Rijk Lambertus thinks that the ‘S is P’ pattern is misleading when it comes to express predication in Aristotle. In his view, ‘The Aristotelian procedure should be described in terms of appositively assigning an attribute (κατηγορούμενον) to a substrate (ὑποκείμενον), rather than ascribing a predicate to a subject by means of a copula…. The comment should be considered an attribute which is said to fall to a substrate, without understanding this procedure in terms of sentence predication.’ e) Aristotle’s predication: bipartite or tripartite? It is a difficulty to make Aristotle’s theories of name-verb predication and tripartite predication consistent. The reason is that tripartite is not consistant with his name-verb structure based on which he says that the predicate term is the ‘verb.’ (20a31; 20b1-2; 16a13-5) The problem is that in a tripartite form like ‘Socrates is white’ we cannot take ‘is white’ as the verb because, based on Aristotle himself, no part of a verb can be significant itself. (16b6-7) However, his assertions about the equivalences between the two structures (OI. 12, 21b9-10; PrA. 51b13-16; Met., 1017b22-30) must mean that they are not inconsistent in his own view. Thus, as Allen Bāck points, ‘Aristotle seems to think that he has a single, consistent theory.’ The sense of saying or speaking as the root sense of rhema makes the relation between predication (saying something of something) and verb more interesting. The use of rhema in the sense of a long expression approves this. In Plato’s work (399ac) where Socrates claims that the name anthropos derives from anthron ha opopen (‘he who examines what he has seen’) we have an onoma from, or in place of, a rhema. 1) Subject The subject (ὑποκειμένον) is that of which another term is said or predicated. Aristotle’s own definition is of a much more philosophical value: ‘By subject I mean that which is expressed by an affirmative term (λέγω δὲ ὑποκείμενον τὸ κάταφάσει δηλούμενον).’ (Met., K, 1067b18) Throughout Aristotle’s work, three kinds of subjects can be found: possible, prime and absolute subject. a) Possible subject Those things that can take the position of a subject in a predication we call possible subjects, no matter they can or cannot take the position of predicate in any predication. All terms except the ultimate predicates are possible subjects because they can take the position of subject. b) Prime subject Those that in any predication can only take the position of a subject and not the position of a predicate are prime subjects. (Cat., 5, 3a36-b2; Met., Z, 1028b36-1029a1) This is the truest sense of subject and belongs only to substances. (Met., Z, 1029a1-2) In fact, ‘that which is not predicated of a subject, but of which all else is predicated’ is a substance. (Met., Z, 1029a7-9) In Categories, besides primary substances (Cat., 2, 1b3-6), individual qualities are also said not to be able to be said of anything else. (Cat., 2, 1a23-29) Aristotle’s examples are a certain ‘knowledge-of-grammar’ (τὶς γράμματικὴ) and ‘an individual white’ (τὸ τὶ λευκὸν). Thus, although substances are indeed in the truest sense individuals and, thereby, in the truest sense primary subjects, other individuals can take the position of subject as well. c) Absolute subject While substances are prime subjects of all other things, there is still something of which substances can be predicated and this predication is not an accidental predication: matter. (Met., Z, 1029a21-24) This predication is, indeed, the predication of a ‘form or this’ on matter and material substance. (Met., Θ, 1049a34-36) The only thing that is absolutely a subject, therefore, and can be a predicate is prime matter (πρώτη ὓλη). (Met., Θ, 1049a24-27) d) Subject and substance The most important thing in being a substance is being a subject: ‘It is because the primary substances are subjects for all the other things and all the other things are predicated of them or are in them, that they are called substances most of all.’ (Cat., 5, 2b15-17) And what is nearer to this position is more a substance as a species is more a substance than a genus.’ (Cat., 5, 2b7-8) e) Primary versus accidental subject A subject is a primary subject in a predication when the predicate is predicated of it as itself. In such a case, the subject is the subject of the predicate qua itself and not qua something else. A subject, on the one hand, is an accidental subject when it is not the primary subject of the predicate that is predicated on it. It means that a subject is an accidental subject when the predicate is predicated of it not qua itself but qua something else. An accidental subject is, therefore, anything other than a substance. 2) Predicate as universal It is evident from our discussion of kinds of subjects that except matter, primary substances (if we ignore both accidental predication and cases of absolute subjects) and other individuals, everything else can take the position of a predicate. Since primary substances are individuals, it results that everything except matter and individuals are capable to take the position of predicate. The immediate consequence of this is that the predicate must be a universal. When individuals cannot take the position of predicate, this position cannot be taken by any particular. Therefore, only universals can be predicated of others. Moreover, albeit universals can be a simple subject (for another universal), they are not prime subjects. The closeness of universal and predicate is to the extent that Aristotle differentiates universal from subject. (Met., Θ, 1049a27-30) 3) Categories or classes of predicates Aristotle distinguishes ten highest classes into one of which each predicate must necessarily fall: substance (or what a thing is), quality, quantity, relation, place, time, position, state, activity and passivity. (Cat., 4, 1b25-27; To., I, 9, 103b20- ; PsA., A, 22, 83b13-23) The substance counted among predicates must refer to secondary and not primary substances not only because Aristotle insists that primary substances cannot be predicated but also from his own examples of the category of substance: man and animal. (To., I, 9, 103b25) However, if a predicate be asserted of itself or its genus be asserted of it, the predicate signifies substance or what is; but if ‘one kind of predicate is asserted of another kind,’ it signifies one of the other nines. (To., I, 9, 103b30) These categories are so comprehensive that no predicate can remain outside them so that even non-being has as many senses as categories. (Met., M, 1089a26-30) a) That whether Aristotle’s categories are merely linguistic or fundamentally ontological is a so much controversial dispute. Some like G. E. R. Lloyd believe that ‘categories are primarily intended as a classification of reality … rather than of the signifying terms themselves.’ b) Although Aristotle’s categories have been historically regarded as a classification of predications, there are some recent commentators like Jonathan Barnes that think it is classifying predicates and not predications. 4) Kinds of predicates In his introduction of Categories, as J. W. Thorp truly points out , Aristotle distinguishes between the category of substance and the other categories using μὲν ... δὲ construction. This construction illustrates that beside tenfold classification of categories, there is an even more crucial differentiation between two kinds of predicates: substance or what is on the one hand and the other nine ones on the other hand: the distinction between what is predicated of the subject as what it is and what is predicated of it as an accident. Therefore, we have three kinds of classification - a twofold, a fourfold and a tenfold-complicatedly classifying the same thing, viz. the predicate. Predicates can be divided also to four kinds: property, definition, genus and accident. (To., I, 4, 101b11-20) A property is that predicate that is convertible with its subject and does not signify its essence. A definition is that predicate that is convertible with its subject and signifies its essence. It is a genus if it is not predicated convertibly and is contained in the definition of its subject. And it is an accident if it is neither convertible nor contained in the definition of its subject. (To., I, 8, ^103b3) All of these four kinds are among categories. (To., I, 9, 103b20) It seems that there might be some kind of relation between the twofold and the fourfold distinction: whereas genus and definition are predicated as what it is, accidents are not so predicated. There seems to be some rules that determine to each of these four kinds each predicate belongs. At To., IV, 123b30ff. Aristotle asserts: ‘If B has a contrary and A does not, then B does not belong to A as its genus.’ There is a dispute around per se accidents (τὰ καθ’ αὑτὰ συμβεβηκότα) (Topics., 102a18) whether they must be regarded as either of the four kinds or as a fifth kind. Barnes (1970) argued that they ‘do not fit at all neatly into the fourfold classification.’ He argues that based on the definition of accidents at A, 5, 102b4-5, they must be accidents but based on another definition, A, 5, 102b6-7, they cannot be accidents. He also defends the view that they are not properties. Barnes concludes: ‘This shows that the two definitions are not equivalent, and hence that the ‘predicables’ are not well-defined.’ Demetris J. Hadgopoulos defends the view that the two definitions of accidents are equivalent and per se accidents are properties. 5) Five types of predications We have five kinds of predications based on our division of subjects and our discussion of predicates: simple, primary (itself divided to substantial and accident), accidental (itself divided to primary and secondary), aoincidental and absolute predication. a) Simple predication. This is a predication in which a universal is predicated of either a particular or a universal subject. This sense of predication includes all other senses except the first kind of accidental predication. b) Primary predication. This is a predication in which a universal is predicated of a primary subject, namely a substance. A primary predication is of two kinds: i) Substantial predication. A primary predication in which the predicate is part of, or is included in, the definition of the subject. The universal that is the predicate here is the definition or the genus or the species or the diferentia of the subject. It is this predication that Aristotle calls a unity: ‘A statement may be called a unity … because it exhibits a single predicate as inhering not accidentally in a single subject.’ (PsA., B, 10, 93b35-37) It is only substantial predicates that can be predicated of each other: ‘Predicates which are not substantial are not predicated of one another.’ (PsA., A, 22, 83b18-19) Aristotle defines a substantial predication also in another way. A predication in which a higher genus is predicated on a lower genus, species, a substance or an individual, (or a species is predicated on an individual) is a substantial predication. Therefore, a substantial predication is a predication in a series that has individuals on one of its ends and a general category on its other end. In fact, only substantial predicates can be predicated of one another. (PsA., A, 22, 83b17-19) This series cannot be an infinite series because otherwise not only substances would not be definable but also a genus would be equal to one of its own species. (PsA., A, 22, 83b7-10) -/- ii) Accident predication. A primary predication in which the predicate is not part of, or is not included in, the definition of its subject. The universal that is the predicate here is the property or the accident of the subject. c) Accidental predication. This is a predication in which the subject is not a primary subject and its predicate is a substance. This predication is of two kinds: i) Primary accidental predication. This is a predication in which an accident is predicated of substance. Such a predication can go ad infinitum, which is inferable from Aristotle’s assertion that the secondary accidental predication cannot go ad infinitum. ii) Secondary accidental predication. It is a predication in which an accident is predicated of another accident. Such a predication, Aristotle asserts, cannot go ad infinitum because even more than two accidents cannot be combined. Now what is the meaning of Aristotle’s assertion that we cannot continue this ad infinitum? Does it mean that we cannot continue the predication ‘The musician is white’ and say ‘The white is Athenian?’ But why not? Or maybe he means that by adding any predication, we are still in a condition of predicating two accidents of a substance on each other. -/- As primary subjects, substances can also take the position of predicate though not essentially but accidentally. In propositions like ‘the white is a log’ or ‘That big thing is a log’ we observe substance taking the position of predicate but this is only accidentally: ‘When I affirm ‘the white is a log,’ I mean that something which happens to be white is a log- not that white is the subject in which log inheres (οὐχ ὡς τὸ ὑποκείμενον τῷ ξύλῳ τὸ λευκόν ἐστι), for it was not qua white or qua a species of white that the white (thing) came to be a log (οὔτε λευκὸν ὄν οὔθ᾿ ὃπερ λευκόν τι ἐγἐνετο ξύλον), and the white (thing) is consequently not a log except incidentally.’ (PsA., 22, 83a3-9) Aristotle compares this accidental use of substance in the position of predicate with the substantial use of it in the place of a subject: ‘On the other hand, when I affirm ‘the log is white,’ I do not mean that something else, which happens to be a log, is white (οὐχ ὃτι ἓτερόν τί ἐστι λευκόν, ἐκείνῳ δὲ συμβέβηκε ξύλῳ εἶναι), (as I should if I said ‘the musician is white,’ which would mean ‘The man who happens also to be a musician is white’); on the contrary, log is here the subject- the subject which actually came to be white, and did so qua wood or qua a species of wood and qua nothing else.’ (PsA., 22, 83a8-14) Aristotle asks us not to call propositions like ‘The white is a log’ a predication at all or at least call them accidental predication instead of simple (ἁπλως) predication. (PsA., A, 22, 83a14-17) An accidental predication, in which we have a substance in the place of predicate, is different from an essential predication in that while the subject of an accidental predication is said to be the predicate not by itself but as something different with which it coincides, the subject of an essential predicate is said to be the predicate by itself and not because it is something else: ‘Since there are attributes which are predicated of a subject essentially and not accidentally- not, that is, in the sense in which we say ‘That white (thing) is a man,’ which is not the same mode of predication as when we say ‘The man is white’: the man is white not because he is something else but because he is man, but the white is man because ‘being white’ coincides with ‘humanity’ within one subject. Therefore, there are terms such as are essentially subjects of predicates. (PsA., A, 19, 81a24-29) This capability of ‘non-essentially and only accidentally’ being a subject does belong, in fact, to all sensible things. (PsA., A, 27a32-36) d) Coincidental predication. this is a predication in which none of the subject and predicate are a substance or an individual. In this predication, one of the accidents of a substance or individual is predicated of one of the other accidentals of the same substance or individual. For example, when it is said that ‘The white is musical,’ there is an individual, say Socrates, for which both of white and musical are accidents. e) Absolute predication. This is a predication in which a form or a substance is predicated of a matter or a material substance. Some commentators like Loux and Lewis regarded this predication as close to accident predication, both based on inherence. As R.M. Dancy points out, these predications make Aristotle’s theory of predication immanentist: not only accident predications are explained by the immanence of accidents in substances, some of the substantial predications, which were not explained in Categories, are also explained by the immanence of form in matter. It is interesting that in this kind of predication, it is the predicate and not the subject, which is in the strictest sense substance. As the central books of Metaphysics claim, the form is the substance. Thus, in this predication, substance gets away from the sense of ὑποκείμενον. Corkum mentiones 68a19 as the only instance where Aristotle explicitly claims that a term may be predicated of itself, a passage that is, in Corkum’s view, problematic. 6) Demonstrable predicates Those predicates are demonstrable that are so related to their subjects that there are other predicates prior to them predicable of their subjects (ἔτι δ᾿ ἄλλος, εἰ ὧν πρότερα ἄττα κατηγορεῖται). (PsA., A, 22, 83b32-34) 7) Series of predications Since it is possible for a predicate to be itself the subject of another predication, we can have a series of predications in which the predicate of a predication is the subject of the next predication. This series has the following features: a) It has a limit (in number) (PsA., A, 22, 83b14-16) on the side of subjects: there are subjects that cannot themselves be predicated (PsA., A, 27, 43a39-41), which are, as we noted, prime subjects: particulars, i.e. prime substances and other individuals. (PsA., A, 19-22) Aristotle calls them ultimate (ὓστατον). (PsA., 21, 82a36-b1) b) It has a limit (in number of kinds) (PsA., A, 22, 83b14-16) also on the side of predicates: there must be predicates that cannot be subjects. (PsA., A, 19-22; PsA., A, 27, 43a36-39) Aristotle calls them primary (πρῶτον). (PsA., A, 21, 82b1-4) These are the highest categories or the highest genera of categories. (PsA., A, 22, 83b14-16) c) The series has an escalating shape from mere subjects at its downside to mere predicates at its upside. It is Aristotle himself whos uses the words up and down in this sense. (e.g. PsA., A, 22, 83b2-3) d) The predications that lie between lowest and highest ones must be finite in number. (PsA., A, 19-22 especially: 20, 82a21-35) These have subjects and predicates, each capable of both of the roles of being subject and being predicated. A result of this fitness is that neither demonstration can go to infinity nor everything is demonstrable, the two points Aristotle always insist on. e) The upward side includes the more universal ones and the downward the more particular ones. (PsA., 20, 82a21-23) f) It follows from the above features that ‘neither the ascending nor the descending series of predications … are infinite.’ (PsA., A, 22, 83b24-25) g) Reciprocation and convertibility. Except in case of terms (i.e. subjects and predicates) that are at each of the ends of series of predications, namely ultimates and primaries, it is possible to reciprocate (ἀντιστρέφειν) terms and convert the predication. (PsA., A, 19, 82a15-20) h) Antipredication. Antipredication means that in a predication (S is P), the subject becomes the predicate of its predicate (P is S) in the same category its predicate was predicated on it. For example, if P is in the category of quality, antipredication means that S be predicated of P in the category of quality. In other words, P is a quality of S and S is a quality of P. Aristotle rejects this. (PsA., A, 22, 83a36-b3) i) Self-predication versus other-predication. Aristotle distinguishes between a predication in which a term is said of itself and a predication in which a term is said of another. (Phy., Δ, 2, 209a31-33) j) Predicablity (Cat., 5, 3a36-b2): 1) Primary substances and individuals are not predicable. 2) Secondary substances are of two kinds: genus and species i) Genus is predicable able both of the species and of the individuals. ii) Species is predicable of the individual. 3) Differentiae are predicable both of the species and of the individuals. 8) Predication as classification a) Richard Patterson believes that Aristotle’s so repeated construction using hoper (estin A hoper B) in Topics (120a23 sq., 122b19, 26sq., 123a, 124a18, 125a29, 126a21, 128a35. Also in Posterior Analytics (83a24-30) (Brunschwig’s list. ‘expresses the fact that A is a kind of B (esti A B tis), that A is a species of the genus B.’ 9) Universal predication Aristotle defines universal predication (κατὰ παντὸς κατηγορεῖσθαι) as such: ‘wherever no instance of the subject (τῶν τοῦ ὑποκειμέμνου) can be found of which the other term cannot be asserted.’ (PrA., A, 24b27-29) In this predication, the subject is included in another as in a whole (ἐν ὃλῳ εἶναι) and the predicate is predicated of all of the subject (κατὰ παντὸς κατηγορεῖσθαι). (PrA., A, 24b26-27) Attach another discussion we had about ἐν ὃλῳ here. 10) Quantity of predication A predication, truly stated, has a quantity, which is the number of objects under the name of the subject of which the predicate is predicated. The quantity of subject can be stated in four ways: a. Indefinite: when the predicate belongs or does not belong to the subject without any mark to show to haw many of the particulars under the name of the subject it does or does not belong. E.g. ‘Man is white’; ‘Man is not white.’ (PrA., A, 24a20; OI., I, 7, 17b8-12) b. Universal quantity: When the predicate belongs to all or none of the subject. E.g. ‘Every man is animal’; ‘No man is animal.’ (PrA., A, 24a18-19; OI., I, 7, 17b5-6) The contrary of a predication of a universal quality is a predication of a universal quality. E.g. the contrary of ‘Every man is white’ is ‘No man is white.’ (OI., I, 7, 17b20-23) c. Particular quantity: When the predicate belongs (or does not belong) to some of the subject. E.g. ‘Some men are white’; ‘Some men are not white.’ (PrA., A, 24a19-20) d. Single quantity: when the subject is a proper name of only one object. E.g. ‘Socrates is white’; ‘Socrates is not white.’ The contrary of this predication is of a single quantity: ‘Socrates is not white.’ (OI., I, 7, 17b38-18a4) 11) Convertibility of predication. Some predications are convertible, that is, it is possible to change the place of subject and predicate in a true proposition so that the converted proposition remains true. This is supposed to mean that given the truth of a predication, the truth of the converted predication is inferable. The convert form of a predication depends on its quantity. a. Indefinite quantity: This predication has no strictly true convert because its quantity is not stated. b. Universal quantity: It can be converted in two ways: i) A negative universal can be converted to a negative universal in which the terms are changed. E.g. ‘No pleasure is good’ can be converted to ‘No good is pleasure.’ (PrA., A, 2, 25a5-8 and a14-19) ii) An affirmative universal can be converted to an affirmative particular in which the terms are changed. E.g. ‘Every pleasure is good’ can be converted to ‘Some good is pleasure.’ (PrA., A, 2, 25a7-9) c. Particular quantity: If it is negative, it cannot be converted but if it is affirmative, it can be converted to an affirmative predication with particular quantity. E.g. ‘Some pleasure is good’ can be converted to ‘Some good is pleasure.’ (PrA., A, 2, 25a10-13 and a20-24) d. Single quantity: It cannot be converted. 12) Characteristics of relations between subject and predicate 1. A predicate is of a wider range than its subject. It is based on this fact that Aristotle: a) Prevents individuals to be predicate because there is nothing of which an individual be of a wider range. In other words, it is due to the fact that since an individual is only ‘one particular’ thing and, thus, cannot be of a wider extent than anything that Aristotle prevents them of being a predicate. Matthews, however, thinks we cannot use Socrates, a substance and an individual, in the place of predicate and say it of Socrates because ‘Socrates does not classify Socrates: it names him.’ b) Prevents differentia, species and things under species to be predicated of genus. (To., Z, 6, 144a27-) c) Prevents the species and the things under it to be predicated of the differentia. (To., Z, 6, 144b1-4) d) Also about the effect because it is wider than its subject. (PsA., B, 17, 99a) e) Each attribute is wider than every individual it is predicated on, though several attributes, collectively considered, might not be wider but exactly the substance of a thing. (PsA., B, 13, 96a32-b1) 2. The predicate of a predicate of a subject will be predicated of the subject too: ‘whenever one thing is predicated of another as of a subject, all things said of what is predicated will be said of the subject too.’ (Cat., 3, 1b10-15) In fact, it is due to its predication of the subject that it is predicated of its predicate. (Cat., 5, 2a36-b1) Moreover, what is not predicated of the predicate of a subject cannot be predicated of it as well. (PrA., A, 27, 43b22-27) Thus, what, for example, is not predicated of animal, cannot be predicated of man. 3. The predicate of a subject can be predicated of its predicates as well. (Cat., 5, 3a1-6) For example, you call the individual man grammatical and, thence, you call both a man and an animal grammatical. Nonetheless, the predicate of a subject belongs to it more properly than to its higher predicates. (PrA., A, 27, 43a27-32) 4. It is only the subject that can be distributed and not the predicate. (PrA., A, 27, 43b16-22; OI, I, 7, 17b12-16) Therefore, we can say e.g. ‘Every man is animal’ but we cannot say ‘Every man is every animal.’ 5. It is the reason of the relation between subjects and predicates, that is the reason of predication, which is the subject of inquiry. (Met., Z, 1041a20-24) In other words, since it is a meaningless inquiry to ask why a thing is itself (Met., Z, 1041a14-15), the only remaining meaningful inquiry is to ask why something is something else, i.e. to ask about the reason of predication. 6. A subject cannot categorize its predicate in the same category in which it is categorized by it. If e.g. A is a quality of B, B cannot be a quality of A. Therefore, there is no reciprocation in the same category. (PsA., A, 22, 83a36-39) 13) Characteristics of series of predications 1. A series of secondary accidental predication cannot go ad infinitum for not even more than two terms can be comnbined. For an accident is not an accident of an accident, unless it be because both are accidents of the same subject. (Met., Γ, 1007b1-4) 2. Infinite series cannot be traversed in thought. (PsA., A, 22, 83b6-7) 3. The predications of genera on each other must be ended and cannot go to infinity because otherwise not only substances would not be definable but also a genus would be equal to one of its own species. (PsA., A, 22, 83b7-10) Therefore, a series of predication of genera on each other must be limited on both sides. There must be an upward limit in general categories as well as a downward limit in individual because they cannot be predicated of others. Whatever lies between these limits can both be predicated of others and others be predicated of them. (PrA., A, 27, 43a36-43) 4. The order of predicates matters: it makes a difference whether the series be ABC or BAC. (PsA., B, 13, 96b25-32) . (shrink)

GAMETOGÊNESE -/- Emanuel Isaque Cordeiro da Silva Instituto Agronômico de Pernambuco Departamento de Zootecnia – UFRPE Embrapa Semiárido -/- • _____OBJETIVO -/- Os estudantes bem informados, estão a buscando conhecimento a todo momento. O estudante de Veterinária e Zootecnia, sabe que a Reprodução é uma área de primordial importância para sua carreira. Logo, o conhecimento da mesma torna-se indispensável. No primeiro trabalho da série fisiologia reprodutiva dos animais domésticos, foi abordado de forma clara, didática e objetiva os mecanismos de diferenciação (...) sexual dos embriões em desenvolvimento, quais os genes envolvidos nesse processo e tudo mais. Nesse segundo trabalho, a abordagem será teórica, mas também clara, sobre a formação primordial dos gametas femininos e masculinos, através da ovogênese nas fêmeas e a espermatogênese nos machos. Esse trabalho visa levar a importância do processo de formação dos gametas e a produção hormonal das gônadas, bem como o entendimento sobre as interações com o eixo hipotálamo-hipofisário. -/- •____INTRODUÇÃO -/- A reprodução sexual é um processo mediante a qual dois organismos da mesma espécie unem seu material genético para dar lugar a um organismo fixo com combinação única de genes; para isso, cada organismo produz células que contém a metade do material genético característico da espécie. Essas células haploides (1n) são denominadas gametas; ao combinar-se um gameta masculino com um feminino produz-se uma célula diploide (2n) (zigoto ou ovo) a partir da qual se forma o embrião. A grande maioria das espécies com reprodução sexual são anisogâmicas, o que significa que produzem dois tipos de gametas diferentes: os gametas masculinos são microscópios, móveis e produzem-se em grande quantidade, enquanto que os femininos são grandes, imóveis e produzem-se em menor quantidade. O tipo de gameta que um indivíduo produz é o que define seu sexo; sobre os animais o macho é o indivíduo que produz grandes quantidades de espermatozoides e a fêmea produz uma menor quantidade de óvulos, enquanto que nas plantas as gônadas masculinas são as produtoras pólen e as femininas produzem oosferas. Os gametas são diferentes do resto das células do organismo, as quais se chamam células somáticas; essas últimas são diploides porque contém dois pares de cromossomos, um par herdado do pai do indivíduo e o outro da mãe. As células somáticas, ademais, se dividem por mitose, ao qual os cromossomos se duplicam antes de cada divisão celular e cada uma das células filhas recebe um complemento diploide idêntico dos cromossomos, logo todas as células somáticas de um indivíduo possuem o mesmo material genético, embora cada tipo celular expresse diferentes combinações de genes. Em contraponto, os gametas são células haploides porque possuem somente um par de cromossomos e a metade do material genético característico da espécie. Cada um dos cromossomos em um gameta é resultado da recombinação dos genes contidos nos cromossomos paterno e materno do indivíduo que originam o gameta, e cada um destes possuem uma combinação única de genes. Os gametas se formam a partir das células germinais, que são células que em sua origem são diploides e elas de “comprometem” a manter-se como uma linha celular especial que em determinado momento sofrerá o processo de meiose para dar origem aos gametas haploides, sejam óvulos ou espermatozoides segundo o sexo do animal. Como descrito no trabalho sobre a diferenciação sexual, as células germinativas primordiais originam-se no epiblasto do embrião, e migram desde o saco vitelino até colonizar as cristas gonodais, onde, por sua vez, proliferam-se e se organizam junto com as células somáticas da gônada primitiva para formar o testículo ou o ovário. As células germinais masculinas e femininas tem a mesma origem embrionária. As gônadas indiferenciadas em um embrião possuem três tipos celulares: as células que dão origem aos gametas (ovogonia ou espermatogonia), as precursoras de células que nutrem os gametas em desenvolvimento (células da granulosa no ovário; células de Sertoli no testículo) e as precursoras de células que secretam hormônios sexuais (células da teca no ovário; células de Leydig no testículo). As células germinais são as únicas estruturas do organismo que têm a capacidade de dividir-se por meiose sofrendo uma redução no número de seus cromossomos, sendo responsável pela transmissão da carga genética aos descendentes. Em contraste, as células somáticas somente se dividem por mitose. A formação dos gametas compreende fases sequenciais de mitose, meiose e pós-meiose. Esses processos são altamente organizados e necessitam de um preciso e bem coordenado programa de expressão genética. Uma das características importantes da gametogênese é a redução cromossômica, que através da meiose, reduz pela metade o número de cromossomos e produz células distintas entre si, devido a trocas de material genético entre os pares de cromossomos provenientes do pai e da mãe, o que ocorre no processo de “crossing over” durante a primeira fase da meiose. A gametogênese é o processo mediante o qual as células germinais de cada sexo se multiplicam, dividem e diferenciam até formar os gametas. No caso da formação dos gametas masculinos o processo recebe o nome específico de espermatogênese, e para os gametas femininos é denominado como ovogênese. Embora os dois processos alcancem o objetivo comum de produção das células haploides, por onde compartilham algumas características, existem diferenças marcadas entre eles devido a necessidade de produzir um número muito distinto de gametas, de tamanho diferente, e com características de motilidade também distintas. -/- •___ESPERMATOGÊNESE -/- A espermatogênese é o processo mediante o qual se produz os gametas masculinos denominados espermatozoides. Durante a vida fetal as células germinais e as células somáticas do testículo em formação organizam-se em túbulos seminíferos que se derivam dos cordões sexuais primários e conformam a maior parte da medula do testículo. Na etapa fetal cada tubo seminífero é delimitado por uma membrana basal, recoberta na parte interior pelas células precursoras das células de Sertoli (um tipo de células somáticas). No exterior do túbulo localizam-se as células precursoras das células de Leydig ou intersticiais (figura 1), que também são células somáticas. Entre a membrana basal e as células de Sertoli encontram-se algumas células germinais denominadas espermatogonias de reserva A0 (denominadas gonócitos) que serão o único tipo de células germinais presentes no testículo enquanto o animal não alcançar a puberdade. As células de Sertoli estabelecem na região basal uniões oclusoras entre si, formando parte da barreira hemato-testicular. As espermatogonias A0 localizam-se por dentro da membrana basal do túbulo seminífero, embora fora da barreira hemato-testicular. Figura 1: fase neonatal. Nota-se a grande infiltração de tecido intersticial em quase 50% da seção originando que os túbulos sejam pequenos e redondos em sua maioria. O citoplasma e núcleo das células pré-Leydig são notadas claramente por essa ser uma espécie suína onde o tecido intersticial está claramente diferenciado. Hematoxilina-eosina (X 220.5). Fonte: Embrapa. -/- O número de células de Sertoli no testículo depende da influência do hormônio folículo estimulante (FSH) presente durante a vida fetal e as primeiras etapas de vida pós-natal. A população de células de Sertoli ao chegar a puberdade se manterá fixa durante o resto da vida do animal; existe uma relação positiva entre o tamanho e a população de células de Sertoli e a capacidade de produção de espermatozoides do testículo. As células de Sertoli são as únicas células somáticas que estão no epitélio seminífero, e sua função é a nutrição, sustentação e controle endócrino das células germinais. As células de Sertoli participam ativamente no processo de liberação dos espermatozoides para a luz do túbulo. Nesse momento, as células de Sertoli realizam a fagocitose de parte do citoplasma do espermatozoide dos chamados corpos residuais. As células de Sertoli também fagocitam as células germinais que se degeneram no curso normal da espermatogênese. Essas células ainda sintetizam grande quantidade de proteínas, como por exemplo as proteínas ABP (androgen hinding protein), que transportam andrógenos para todo o aparelho reprodutivo, transferrinas, que transportam ferro para a respiração celular das células germinais e também às inibinas, que regulam a liberação de FSH pela hipófise, através de um sistema de retroalimentação (feedback) negativa (figura 2). Figura 2: epitélio seminífero, células de Sertoli (flecha) (400 X). Fonte: Embrapa. -/- Antes da puberdade dos túbulos seminíferos observam-se ao corte como estruturas de diâmetro pequeno, sem luz, e conformados unicamente pelas células de Sertoli e espermatogonias de reserva e rodeados por abundante tecido intersticial, ao que estão presentes as células precursoras das células de Leydig. Ainda antes da puberdade, a diferenciação celular manifesta-se primeiro pela presença de espermatócitos primários, os quais se degeneram em geral na fase de paquíteno, por falta de estimulação hormonal. A partir de que o animal chega a puberdade inicia-se o processo de espermatogênese, que se manterá durante toda a vida do animal, exceto em espécies de animais silvestres muito estacionais, ao qual pode se suspender durante a época não reprodutiva para voltar e ser retomada na época ou estação reprodutiva. Depois da puberdade, os túbulos seminíferos possuem um diâmetro muito maior; em seu interior observa-se um grande número de células germinais de todos os tipos, diferentes estádios de divisão, e em seu lúmen contém líquido e espermatozoides. Ainda sobre o alcancei da puberdade, as espermatogonias começam a dividir-se aceleradamente por mitose, enquanto que no espaço intersticial as células mesenquimais também começam a se diferenciar e a dar origem as células de Leydig (figura 3). A partir dessa etapa as células de Leydig (totalmente diferenciadas) são também evidentes no exterior do túbulo, junto com as células mioides ou peritubulares que o rodeiam o que ao contrair-se são responsáveis por controlar o avanço dos fluidos e as células presentes no lúmen do túbulo. As células mioides estão situadas ao redor do túbulo, e é creditado a elas a promoção da contração e da integridade estrutural do túbulo. Esse tipo celular apenas se diferencia na puberdade pela ação dos andrógenos (figura 4). As interações entre as células de Sertoli e as mioides parecem ter um papel importante na manutenção das funções do testículo. Durante o processo de espermatogênese, as espermatogonias de reserva dividem-se periodicamente e enquanto algumas células fixas permanecem como espermatogonias de reserva, outras proliferam e sofrem uma seção de divisões mitóticas durante as quais se vão diferenciando até formarem espermatócitos primários (espermatocitogênese ou fase de mitose), logo sofrem divisões especiais mediante as quais reduzem seu número de cromossomos (fase de meiose), e ao final trocam de forma para converter-se em espermatozoides (espermatocitogênese) (figura 5). Cada uma dessas etapas da espermato- gênese será descrito detalhadamente adiante, antes é necessário a explicação de algumas características das células de Sertoli e de Leydig que ajudarão a entender seu papel durante a espermatogênese. Figura 3: células de Leydig no espaço intersticial do testículo bovino adulto PAS (400 X). Fonte: Embrapa. -/- Figura 4: o estabelecimento da puberdade pela presença de espermatozoides no túbulo. Hematoxilina-eosina (400 X). Fonte: Embrapa. Figura 5: fases mitóticas das espermatogonias (A0 e B) para formação de um espermatócito primário e as duas fases de meiose que se sucedem antes da espermatogênese. Fonte: ZARCO, 2018. -/- Ao início da espermatocitogênese as uniões oclusoras entre as células de Sertoli se abrem por etapas (como as comportas de um submarino) para permitir a passagem das espermatogonias em direção ao centro do túbulo seminífero sem que se estabeleça uma continuidade entre o exterior e o interior da barreira hemato-testicular. Uma vez ultrapassada essa barreira, as sucessivas gerações de espermatogonias, espermatócitos, espermátides e espermatozoides irão se localizar em direção ao interior do túbulo seminífero, em estreita associação com as células de Sertoli. Em consequência, as células de Sertoli dividem o túbulo seminífero em dois compartimentos; o compartimento basal (debaixo das uniões oclusoras das células de Sertoli), ao qual residem as espermatogonias de reserva, e o compartimento adluminal (em direção ao centro do túbulo), cujos espaços entre as células de Sertoli desenvolvem o resto do processo de espermatogênese (meiose e espermatocitogênese). Esse feito é importante porque durante a vida fetal as únicas células germinais existentes eram as espermatogonias de reserva, pelo que os antígenos expressados por gerações mais avançadas (espermatogonias intermediárias, secundárias, espermátides e espermatozoides) não são reconhecidos como próprios do corpo pelo sistema imunológico. Logo, o anterior implica que deve existir uma barreira entre eles e o sangue para evitar um ataque imunológico. Em todas as etapas da espermatogênese, as células de Sertoli atuam como células de suporte para as células germinais, que sempre permanecem recoberta pela membrana das células de Sertoli. Também atuam como células nutricionais já que proporcionam o meio em que as células germinais se desenvolvem e maturam, assim como as substâncias que regulam e sincronizam as sucessivas divisões e transformações das células germinais. As células de Sertoli produzem hormônios, como estrógenos e inibina que atuam sobre a hipófise para regular a secreção das gonadotropinas que controlam a espermatogênese. As células de Leydig que residem no exterior do túbulo seminífero também são importantes para a espermatogênese: produzem a testosterona que estimula e mantém a espermatogênese, bem como serve como substrato sobre o qual atua como aromatizador das células de Sertoli para transformá-las em estrógenos. Como supracitado, para seu estudo podemos dividir a espermatogênese em três fase: espermatocitogênese, meiose e espermiogênese (figura 6). Agora, serão descritas cada uma dessas etapas. Em algumas espécies, incluindo no homem, os macrófagos representam o segundo tipo celular intersticial mais numeroso no testículo, depois das células de Leydig. Os macrófagos e vários subtipos de linfócitos são identificados nós testículos de ovinos e ratos. Eles estão intimamente associados com as células de Leydig e atuam juntamente na regulação da esteroidogênese. Figura 6: fluxograma da espermatogênese. -/- Espermatocitogênese -/- A espermatocitogênese, também chamada de etapa proliferativa ou de mitose, consiste numa série de divisões mitóticas sofridas pelas células descendentes de uma espermatogonia de reserva. Uma vez que a célula se divide, abandona o estado de reserva e começa um processo de diferenciação. As espermatogonias de reserva (denominadas espermatogonias A0 na rata ou As nos humanos) são células que existem desde a vida fetal e que permanecem mitoticamente inativas durante a infância. Uma vez que alcançam a puberdade começam a dividir-se em intervalos regulares, e as células filhas podem permanecer como espermatogonias de reserva ou abandonar a reserva e ingressar na dita espermatocitogênese. Uma vez abandonada a reserva, as células filhas que vão se formando em cada divisão permanecem unidas por pontes citoplasmáticas, constituindo um clone que se divide sincronicamente. As células que se formam depois de cada divisão continuam sendo espermatogonias, porém cada geração é ligeiramente diferente da anterior. Na rata, por exemplo, as espermatogonias tipo A0 ao dividir-se originam espermatogonias do tipo A1, que em sucessivas divisões formam espermatogonias dos tipos A2, A3 e A4, as quais, por sua vez, sofrem outra mitose para formar espermatogonias intermediárias e uma mais para formar espermatogonias do tipo B. Essas últimas se diferenciam (sem se dividir) em espermatócitos primários, processo em que termina a fase de espermatocitogênese, que literalmente significa processo de geração de espermatócitos. As espermatogonias tipo A0 são a fonte para a contínua produção de gametas. A metade delas se dividem e formam células iguais (as chamadas células tronco) e a outra metade forma as espermatogonias A1, que sofre novas divisões mitóticas e formam os tipos 2, 3 e 4. O tipo A4 sofre mitose para formar a intermediária (A In), que por mitose, forma a tipo B (figura 6). Esses tipos de espermatogonias podem ser identificadas em evoluções histológicas de acordo com sua organização topográfica na membrana basal dos túbulos seminíferos ou mediante seu conteúdo de heterocromatina. Outra maneira de diferenciação se baseia em marcadores moleculares específicos que distinguem as espermatogonias tronco (A0) das demais, com os fins de isolamento, desenvolvimento in vitro e transplante. As tipo B passam por mitose para formarem os espermatócitos primários; estes iniciam a primeira etapa da meiose formando os espermatócitos secundários; na segunda etapa da divisão meiótica, cada espermatócito secundário se divide e formam as chamadas espermátides. Quando o testículo alcança seu desenvolvimento total, a meiose completa-se e as espermátides originadas se convertem em espermatozoides. Um dos maiores sinais característicos desse fenômeno é o alargamento das espermátides e sua migração em direção ao lúmen do túbulo seminífero (figuras 4, 7 e 8). Figura 7: espermatogonias marcadas por imuno-histoquímica, anticorpo monoclonal TGFa (400 x). Figura 8: fases de divisões meióticas (M), espermatócitos em paquíteno (PA) e espermatócitos secundários (ES). -/- Figura 9: estádio posterior a liberação dos espermatozoides na luz do túbulo. Hematoxilina-eosina (400 x). Mediante as seis divisões mitóticas que ocorrem durante a espermatocitogênese se forma potencialmente um clone de 64 espermatócitos primários a partir de cada espermatogonia A que ingressa sobre o processo. Não obstante, algumas células sofrem apoptose em cada uma das etapas do processo, ao qual o número real formado é menor. Em outras espécies produzem-se um transcurso similar de divisões mitóticas sucessivas durante a espermatocitogênese, embora a nomenclatura utilizada possa ser distinta, por exemplo nos bovinos as duas últimas divisões mitóticas dão origem as espermatogonias de tipo B1 e B2. -/- Meiose -/- Uma vez que as espermatogonias B se diferenciam em espermatócitos primários, esses iniciam a etapa de meiose, com uma nova divisão; desta vez a divisão é do tipo meiótica. Ao completar-se a primeira divisão meiótica (meiose I) se obtém os espermató-citos secundários, que ao sofrer a segunda divisão meiótica (meiose II) dão origem as espermátides. Vale salientar que a meiose é o processo mediante o qual reduz-se a metade do número de cromossomos, pelo que as espermátides que se obtém são células haploides (1n). Os espermatócitos secundários que se formam depois da primeira divisão meiótica contém a metade do número normal de cromossomos, porém a mesma quantidade de DNA já que cada cromossomo é duplo. As espermátides formadas na conclusão da segunda divisão meiótica (figura 7), por sua vez, contém a metade dos cromossomos, e esse já não são duplos, já que se trata de células 1n. Também deve-se enfatizar que durante a meiose é relevante o entrecruzamento dos cromossomos homólogos, pelo que cada espermátide possui uma combinação única e diferente de genes paternos e maternos. Outro ponto que deve ser levado em consideração é que cada espermátide somente possui um cromossomo sexual; a metade das espermátides contém o cromossomo X herdado da mãe do macho que está levando a cabo a espermatogênese e a outra metade contém o cromossomo Y herdado de seu pai. Para cada espermatócito primário que entra no processo de meiose obtém-se cerca de quatro espermátides, pelo qual ao ser completada a meiose potencialmente se poderiam formar até 256 espermátides por cada espermatogonia que abandona a reserva e ingressa na espermatocitogênese. -/- Espermiogênese -/- Durante a espermiogênese, também chamada de fase de diferenciação, as esper-mátides sofrem, sem se dividir, uma metamorfose que as transforma em espermatozoides, os quais finalmente são liberados das células de Sertoli em direção ao lúmen do túbulo seminífero. A espermiogênese é um processo complicado e longo já que a espermátide deve sofrer complexas trocas nucleares, citoplasmáticas e morfológicas que resultam na forma-ção dos espermatozoides. Algumas dessas mudanças incluem a condensação do material nuclear para formação de um núcleo plano e denso, a eliminação do citoplasma para a constituição de uma célula pequena, a formação de uma estrutura especializada denomi-nada acrossomo ou tampa cefálica, e a formação do pescoço e da cauda (flagelo) do esper-matozoide, do que depende a sua motilidade. Durante a maior parte da espermiogênese, as espermátides se mantém com uma estreita associação com as células de Sertoli; logo, chega-se a observar, então, flagelos que se projetam em direção a luz do túbulo que pare-cem sair das células de Sertoli, sendo na realidade os flagelos dos espermatozoides que ainda não tinham sido liberados pelo lúmen. Ao liberar os espermatozoides em direção a luz do túbulo, as células de Sertoli realizam a fagocitose de parte do citoplasma dos espermatozoides (corpos residuais). Também fagocitam os restos de todas as células germinais que sofrem apoptose ou degeneram-se durante a espermatogênese. Credita-se que ao realizar essas funções as células de Sertoli podem fazer uma monitoração eficiente da espermatogênese, o que lhes permitiria emitir sinais para colaborar na regulação desse processo em nível gonodal e a nível sistêmico através da secreção de hormônios como a inibina e o estradiol. Além da inibina e activina, as células de Sertoli sintetizam outras proteínas, como a ABP (proteína ligadora de andrógenos) que serve como uma molécula de transporte de andrógenos dentro dos túbulos seminíferos, ductos deferentes e epidídimo, ou a transfer-rina, que transporta o ferro necessário para a respiração celular. -/- Resultados da espermatogênese -/- O resultado da espermatogênese não significa apenas uma simples multiplicação das células germinais (até 256 espermatozoides a partir de cada espermatogonia A1), senão que através dela são produzidos gametas haploides pequenos, móveis e com grande diversidade genética entre eles, ao mesmo tempo que se mantêm uma reversa de células mãe (espermatogonias A0) a partir das quais se poderiam originar novos ciclos de esper-matogênese durante o resto da vida do animal. -/- Controle hormonal da espermatogênese -/- Como mencionado, o FSH reproduz um importante papel para o estabelecimento das células de Sertoli durante a vida fetal e início da vida pós-natal. O começo da esper-matogênese também é estimulado pelo FSH, que atua sobre as células de Sertoli para estimular sua função e a ativação de sinais dessas células em direção as células germinais, incluindo-as a abandonar a reserva e ingressar na espermatogênese. O FSH, assim mesmo, estimula a mitose durante o resto da espermatogênese e aumenta a eficiência do processo, já que reduz a apoptose e a degeneração de espermatogonias intermediárias e do tipo B. O FSH também estimula as células de Sertoli para produzirem inibina e ABP. Uma vez iniciada a espermatogênese somente requerem níveis baixos de FSH para se mantê-la. As células de Sertoli também devem ser estimuladas pela testosterona para funcio-nar de maneira adequada; se requer também do LH hipofisário: hormônio que estimula as células de Leydig para produzir testosterona. Por sua vez, a secreção de LH e FSH é regulada pelo GnRH hipotalâmico: esse neurohormônio também faz parte do mecanismo de regulação da espermatogênese. A espermatogênese também é modulada em nível local mediante a produção de determinados fatores e interações entre as células. Dentro dos fatores locais podemos mencionar o fator de crescimento parecido com a insulina 1 (IGF-1), o fator de crescimen-to transformante beta (TGF- β), activina, ocitocina e diversas citocinas. Entre as intera-ções celulares existem tanto uniões de comunicação entre as células de Sertoli e as células germinais, como pontes citoplasmáticas entre todas as células germinais que formam o clone de células descendentes de uma espermatogonia A1. Uma vez que as células de Sertoli iniciam sua função na puberdade é possível manter experimentalmente a espermatogênese somente com testosterona, sem ser requeri-dos nenhum outro hormônio. A quantidade de espermatozoides produzidos, no entanto, é maior quando há presença do FSH. Abaixo do estímulo do FSH as células de Sertoli produzem estradiol e inibina, hormônios que geram uma retroalimentação sobre o eixo hipotálamo-hipofisário para a regulação da secreção de gonadotropinas. Em particular, a inibina reduz a secreção de FSH, pelo qual é factível que sirva como um sinal que evite uma excessiva estimulação as células de Sertoli. -/- Ciclo do epitélio seminífero -/- Em cada espécie as espermatogonias de reserva iniciam um novo processo de divi-sões celulares em intervalos fixos: a casa 14 dias no touro; 12 dias no garanhão e a cada 9 dias no cachaço (reprodutor suíno). A nova geração de células que começam a proliferar sobre a base do tubo deslocam-se em direção ao centro do túbulo a geração anterior, que por sua vez deslocam-se as gerações anteriores. Devido as mudanças que vão sofrendo cada geração celular se ajustam a tempos característicos de cada etapa, já que rodas as células em uma determinada seção do túbulo estão sincronizadas entre si pelas células de Sertoli; em cada espécie somente é possível encontrar um certo número de combinações celulares: 14 diferentes combinações no caso da rata, 8 no touro e 6 no ser humano. A sucessão de possíveis combinações até regressar a primeira combinação se conhece como o ciclo do epitélio seminífero. Na maioria das espécies os espermatozoides que são libera-dos em direção a luz do túbulo provém das células que entraram no processo de esperma-togênese quatro gerações antes que a geração que está ingressando nesse momento, pelo que a espermatogênese no touro dura ao redor de 60 dias e um pouco menos em outras espécies domésticas. Significa que os efeitos negativos das alterações na espermatogêne-se podem estar presentes até dois meses depois de que se produziram essas alterações. Como supracitado, geralmente se observa a mesma combinação celular em toda a área de uma determinada secção transversal do túbulo seminífero. No entanto, se fizermos uma série de secções, observa-se que ao longo do túbulo há uma sucessão ordenada de combinações (a primeira em uma determinada secção; a segunda combinação na seguinte secção, e assim sucessivamente em secções subsequentes até regressar a primeira combi-nação. Teremos, então, que ao início da divisão das espermatogonias A1 se produz de forma sincronizada em uma secção do túbulo, e vai-se transmitindo como uma onda peristáltica as secções adjacentes. Esse processo é denominado como onda do epitélio seminífero e graças à esse túbulo seminífero sempre tem secções em todas as etapas da espermatogênese, com o que se alcança uma produção constante de espermatozoides. -/- Alterações da espermatogênese -/- Nas espécies estacionais a espermatogênese, como já mencionado, pode reduzir-se ou inclusive suspender sua atividade fisiológica durante a época não reprodutiva dessas espécimes, porém esse processo fisiológico não pode ser considerado como uma altera-ção. No entanto, a espermatogênese só pode ser alterada pelas enfermidades ou por fatores externos. A principal causa de alterações na espermatogênese é o aumento da temperatura testicular. Por isso, os testículos são localizados na saco escrotal e são “caídos” para fora do corpo como pode-se observar nos bovinos, caprinos, ovinos, caninos e no próprio homem. A temperatura testicular deve estar cerca de 2 a 6 °C abaixo da temperatura corporal normal. As células germinais masculinas são sensíveis ao calor, pelo qual na maioria dos mamíferos os testículos se encontram fora da cavidade abdominal e existe um sofisticado sistema de termorregulação para mantê-los a uma temperatura menor que a corporal. Se a temperatura corporal for elevada ou se os testículos permanecerem na cavidade abdominal, ou ainda se os sistemas termorreguladores do testículo sejam afetados por fatores inflamatórios como edema ou falta de mobilidade testicular dentro do escroto, a temperatura do tecido testicular aumentará e a espermatogênese sofrerá alterações proporcionais ao excesso de temperatura e a duração da elevação. A espermatogênese também pode ser afetada pela exposição a hormônios ou a outras substâncias. É possível que a causa mais comum (sobretudo no homem) seja o uso de esteroides anabólicos, que elevam a concentração de andrógenos na circulação, provo-cando um feedback negativo sobre a secreção de gonadotropinas. Ao deixar de estimular-se o testículo pelas gonadotropinas, este deixará de produzir testosterona, e as concentra-ções de andrógeno exógeno nunca alcançará as altíssimas concentrações de testosterona que normalmente estão presentes a nível do tecido testicular por ser o local onde se produz o hormônio. Também se supõe que diversas substâncias com propriedades estrogênicas derivadas de processos industriais (indústria dos plásticos, hidrocarbonetos etc.) e presentes no ambiente (fatores xenobióticos) podem ser responsáveis pelas alterações na espermatogênese em diversas espécies, entre as quais se inclui o ser humano. -/- • OVOGÊNESE E FOLICULOGÊNESE -/- A ovogênese é o processo seguido pelas células germinais da fêmea para a forma-ção dos óvulos, que são células haploides. Durante a vida fetal as células germinais proliferam-se no ovário por mitose, formando um grande número de ovogonias, algumas das quais se diferenciam em ovócitos primários que iniciam sua primeira divisão meiótica para deter-se na prófase da divisão. Somente alguns desses ovócitos primários retornarão e concluirão a primeira divisão meiótica em algum momento da vida adulta do animal, dando origem a um ovócito secundário e a um corpo polar. O ovócito secundário inicia a sua segunda divisão meiótica, a qual volta a ficar suspensa até receber um estímulo apropriado, já que somente os ovócitos secundários que são ovulados e penetrados por um espermatozoide retornam e concluem a segunda divisão meiótica, dando origem a um óvulo (figura 10). O processo de ovogênese é realizado dentro dos folículos ovarianos, que também tem que sofrer um longo transcurso de desenvolvimento e diferenciação denominado foliculogênese pelo que a ovogênese como tal realiza-se dentro do marco desse último processo. Por essa razão, na seguinte seção descreverei tanto a ovogênese como a folicu-logênese, e a relação que existe entre ambos. Figura 10: representação da ovogênese. Na etapa de proliferação, as células germinais se diferen-ciam por mitose. A meiose I se caracteriza por uma prófase prolongada, ocorrendo a duplicação do DNA. Nas duas divisões, que ocorrem antes da ovulação e depois da fertilização, a quantidade de DNA é reduzida a 1n, com o fim de que a fusão dos pronúcles (singamia) pós-fertilização, seja gerado um zigoto com um número de cromossomos de 2n (diploide). -/- Geração de ovócitos primários e folículos primordiais Tanto a ovogênese como a foliculogênese iniciam-se durante a vida fetal, quando as células germinais primordiais provenientes do saco vitelino colonizam a gônada primitiva e, junto com as células somáticas z organizam-se para a formação dos cordões sexuais secundários, que se desenvolvem principalmente no córtex do ovário. Nesse período, as células germinais que colonizaram o ovário sofrem até 30 divisões mitóticas, proliferando-se até formar milhares ou milhões de ovogonias, que inicialmente formam “ninhos” constituídos cada um deles por um clone de várias ovogonias que descendem da mesma célula precursora e que se mantêm unidas por pontes citoplasmáticas, sincronizan-do suas divisões mitóticas. Nessa etapa alcança-se a máxima população de células germinais no ovário, que antes de nascer se reduzirá drasticamente por apoptose. No ovário do feto humano chegam a haver até sete milhões de células germinais que ao nascimento se reduzem a dois milhões. Os ovários fetais do bovino, de maneira análoga, chegam a ter até 2.100.000 células germinais, que ao nascimento reduzem para 130.000 aproximadamente. A redução no número de ovogonias produz-se ao mesmo tempo que essas células, que vêm dividindo-se por mitose e estão agrupadas em ninhos, iniciam sua primeira divisão meiótica para se transformarem em ovócitos primários: células germinais que se encontram em uma etapa de suspensão (diplóteno) da prófase da primeira divisão meiótica. Nesse período produz-se uma grande proporção de células germinais; as células somáticas dos cordões sexuais, por sua vez, emitem projeções citoplasmáticas que separam a isolam os ovócitos primários sobreviventes, ficando cada um deles rodeados por uma capa de células aplanadas da (pré) granulosa. Ao mesmo tempo em que se forma uma membrana basal entre as células da granulosa e o tecido intersticial do ovário. Ao ovócito primário rodeado de uma capa de células da (pré) granulosa aplanadas e delimita-das por uma membrana basal denomina-se de folículo primordial (figura 11). Nas vacas os folículos primordiais bem formados já estão presentes nos ovários a partir do dia 90 da gestação. A maioria dos folículos primordiais com os que nasce uma fêmea se manterão inativos durante um longo tempo; muitos deles durante toda a vida do animal. Nos folículos primordiais inativos tanto os ovócitos primários como as células da granulosa conservam sua forma original e mantém um metabolismo reduzido estritamente ao mínimo necessário para manter-se viáveis. Por essa razão, ao realizar um corte histológico de qualquer ovário as estruturas mais numerosas que se observam serão os folículos primordiais. No entanto, cada dia da vida de um animal, inclusive desde a vida fetal, um certo número de folículos primordiais reiniciam seu desenvolvimento, e a partir desse momento um folículo exclusivamente pode ter dois destinos: o primeiro, prosseguir seu desenvolvi-mento até chegar a ovular, e o segundo (que é muito mais frequente) encontrar em algum momento condições inadequadas que fazem fronteira com ele para parar seu desenvolvi-mento, levando-o a sofrer atresia e degenerar até desaparecer do ovário. Figura 11: sequência da foliculogênese apresentando as diferentes estruturas que podemos encontrar em cada fase. Fonte: ZARCO, 2018. Culminação da ovogênese A ovogênese somente se completará quando um ovócito primário reinicia a meio-se; completa sua primeira divisão meiótica para formar um ovócito secundário e um primeiro corpo polar e, quando, finalmente sofrer uma segunda divisão meiótica para formar um óvulo e um segundo corpo polar. Os óvulos são as células 1n que constituem os gametas femininos, pouco numerosos, grandes e imóveis. A grande maioria dos ovóci-tos primários, como veremos mais adiante, nunca retomam a meiose e, em consequência, não chegam a formar ovócitos secundários, e muitos dos ovócitos secundários tampouco sofrem uma segunda divisão meiótica, pelo que não chegam a formar os óvulos. Ao longo da vida de uma fêmea, na maioria das espécies, menos de 0,1% dos ovócitos primários (um a cada mil) chega a terminar a ovogênese, dando origem a um óvulo. O supracitado deve-se a que a ovogênese somente pode retomar-se e ser completa-da em ovócitos primários que se encontram dentro dos folículos primordiais que (uma vez ativados) vão alcançando diversas etapas de seu desenvolvimento em momentos precisos aos que encontram as condições ideais de oxigenação, nutrição, vascularização e exposição a fatores parácrinos e a exposição a concentrações de hormônios que se requerem para que o folículo continue em cada etapa de seu desenvolvimento com o processo de foliculogênese até chegar a ovular. Qualquer folículo que não esteja nessas condições ao longo do desenvolvimento sofrerá degeneração e atresia, pelo que o ovócito primário em seu interior nunca chegará ao ponto em que pode retomar a primeira divisão meiótica. No que resta da presente seção revisaremos o processo de foliculogênese em cujo marco se desenvolve a ovogênese; havemos que tomar de conta que essa última se limita ao que ocorre nas células germinais (ovogonia, ovócito primário, secundário e óvulo), pelo qual depende intimamente do desenvolvimento do folículo de que essas células formam parte. Em um princípio a ativação do folículo primordial e o desenvolvimento folicular são independentes das gonadotropinas: não se conhecem os mecanismos precisos median-te os quais um folículo primordial se ativa e reinicia seu desenvolvimento, nem como se decide quais folículos, dentre as dezenas de milhares de ou centenas de milhares presentes em um ovário se reativarão em um dia em particular. A reativação trata-se de uma liberação de influência de fatores inibidores, já que os folículos primordiais se reativam espontaneamente quando cultivados in vitro, isolados do resto do tecido ovariano. Uma vez que um folículo primordial se ativa, inicia-se um longo processo de desenvolvimento que somente depois de vários meses (ao redor de cinco meses no caso dos bovinos) o levará a um estádio em que seu desenvolvimento posterior requer a presença das gonado-tropinas; daí que se diz que as primeiras etapas do desenvolvimento são independentes das gonadotropinas. Durante a fase independente de gonadotropinas, um folículo primordial que tenha sido ativado e tenha começado a crescer; passará primeiro para a etapa de folículo primá-rio, caracterizada por conter um ovócito primário que está rodeado, por sua vez, por uma capa de células da granulosa, que não são planas, e sim cúbicas. Depois, se o folículo continuar crescendo se transformará em um folículo secundário, ao qual as células da granulosa começam a proliferar (aumentando em número) e se organizam em duas ou mais capas que rodeiam o ovócito primário. Entre o ovócito e as células da granulosa que o rodeiam se forma nesta uma zona pelúcida; ainda assim o ovócito mantém contato direto com essas células, mediante o estabelecimento de pontes citoplasmáticas que atravessam a zona pelúcida. Através dessas pontes citoplasmáticas as células da granulosa podem passar nutrientes e informação ao ovócito primário. O volume e o diâmetro do ovócito primário aumentam ao mesmo tempo que as células da granulosa proliferam-se, para incrementar as capas ao redor do ovócito. De maneira gradual o citoplasma do ovócito primário aumenta até 50 vezes seu volume e a proliferação das células continua. Esses folículos que possuem cada vez mais células e portanto mais capas de células da granulosa se denominam folículos secundários. Para evitar confusões, há a necessidade de nomen-clatura ao qual o folículo vá mudando de nome de primordial a primário e logo, de secun-dário, a terciário, por sua vez, o ovócito que encontra-se em seu interior, a todo momento, segue sendo um ovócito primário. Durante a etapa dependente de gonadotropinas, os folículos secundários começam a formar um espaço cheio de líquido, o antro folicular, desse modo se convertem em folí-culos terciários. Com a utilização de outra nomenclatura, a formação do antro marca a transição entre folículos pré-antrais (sem antro) e folículos antrais (com antro). Em algum momento dessa transição entre folículo secundário e terciário, também aparece a depen-dência de folículos em direção as gonadotropinas, pelo qual somente podem seguir crescendo na presença do hormônio luteinizante (LH) e do hormônio folículo estimulante (FSH). Nos bovinos e em outras espécies (para seu estudo), os folículos antrais são dividi-dos em pequenos, médios e grandes. Embora todos eles possuam um antro folicular, dependendo do seu grau de desenvolvimento requerem diferentes concentrações de gona-dotropinas para continuar o crescimento. Os folículos antrais mais pequenos somente re-querem concentrações baixas de LH e FSH, pelo qual podem continuar crescendo em qualquer momento do ciclo estral inclusive em animais que não estão ciclando (fêmeas em anestro pré-puberal, gestacional, lactacional, estacional). Nas etapas posteriores os folículos antrais requerem primeiro concentrações elevadas de FSH, e nas etapas finais somente podem continuar crescendo na presença de pulsos frequentes de LH, pelo qual somente os folículos que encontram-se sob concentrações apropriadas desses hormônios podem seguir crescendo. Por essa razão, nos animais que se encontram em anestro de qualquer tipo somente é possível encontrar folículos antrais pequenos ou médios, segundo a espécie, e nos animais que se encontram ciclando (estro) o maior tamanho folicular encontrado em um determinado dia do ciclo dependerá das concentrações de FSH e LH presentes nesse momento e nos dias anteriores. Um folículo que chega ao estado máximo de desenvolvimento, conhecido como folículo pré-ovulatório, ao final, somente chegará a ovular se for exposto a um pico pré-ovulatório de LH. Como supracitado, cada dia na vida de uma fêmea inicia seu desenvolvimento um certo número de folículos; a grande maioria sofrem atresia, mas depois da puberdade em cada dia do ciclo estral um ou vários folículos vão encontrando ao longo do seu desenvol-vimento concentrações hormonais que lhes permite chegar na etapa de folículo pré-ovula-tório. Somente nestes folículos, e como consequência de um pico pré-ovulatório de LH, se reinicia e completa-se a primeira divisão meiótica do ovócito primário, produzindo duas células distintas. Uma delas é o ovócito secundário, que retém praticamente todo o citoplasma. Contém, assim mesmo, em seu núcleo um par de cromossomos duplos, a outra é o primeiro corpo polar, que é exclusivamente um núcleo com uma quantidade mínima de citoplasma. Na maioria das espécies ovula-se um ovócito secundário que se encontra, então, suspendido na segunda divisão meiótica. Esta segunda divisão meiótica somente reinicia-rá e completarar-se uma vez que o espermatozoide começa a penetrar sob o ovócito secundário. Ao concluir-se a divisão se forma o segundo corpo polar e completa-se a ovogênese com o qual se obtém o óvulo, célula 1n que constitui o gameta feminino. No entanto, o óvulo existe pouco tempo como tal, já que em poucos minutos/horas (depen-dendo da espécie) se produzirá a fusão do núcleo do mesmo (pró-núcleo feminino) com o do espermatozoide (pró-núcleo masculino), com o qual se completa a fertilização e se forma um novo indivíduo (o ovo ou zigoto). -/- Ondas foliculares -/- Como mencionado supra, todos os dias um determinado número de folículos pri-mordiais se ativam e começam a crescer, os quais crescem em um ritmo característico em cada espécie. Isso provoca que em qualquer momento existam nos ovários folículos pri-mordiais (que começam a crescer em alguns dias ou semanas), assim como folículos secundários em diversas etapas do desenvolvimento, os quais iniciaram seu desenvolvi-mento em semanas ou inclusive meses (segundo o grau de desenvolvimento atual). Também em qualquer momento poderá haver folículos antrais nas etapas iniciais de seu desenvolvimento (com antros que já se podem detectar em cortes histológicos mas não são visíveis macroscopicamente). Todos esses folículos chegaram até seu estado de de-senvolvimento atual (primário, secundário ou antral pequeno), independente da etapa do ciclo estral em que sejam observados ou encontrados. Nos bovinos, os folículos que chegam ao início da etapa antral iniciaram seu desenvolvimento cinco meses antes, e todavia requerem ao redor de 42 dias para chegar ao estado pré-ovulatório. Para continuar seu desenvolvimento, os folículos antrais pequenos devem encon-trar concentrações altas de FSH, que os estimulam para prosseguir o crescimento. Cada vez que se produz uma elevação nas concentrações de FSH, esse hormônio estimula o desenvolvimento de um grupo de folículos antrais pequenos, que começaram a crescer muito tempo antes e que o dia da elevação de FSH tenha alcançado o grau de desenvolvi-mento preciso para responder com eficiência a este hormônio, o qual atuará através de seus receptores nas células da granulosa para estimular a produção de estradiol, a secreção de inibina, a produção de líquido folicular e a proliferação das células da granulosa. Um grupo de folículos antrais pequenos é assim recrutado pelo FSH para acelerar seu cresci-mento e aumentar sua produção de estradiol e inibina (figura 12). Mediante um seguimento ultrassonográfico dos ovários é possível identificar pou-cos dias depois um certo número de folículos, que por haver sido recrutados começam um período de crescimento acelerado. Durante alguns dias vários folículos crescem juntos, porém depois um deles é selecionado para continuar crescendo, enquanto que o restante do grupo deixam de fazê-lo e terminam sofrendo atresia. Através da ultrassom é possível identificar o folículo selecionado, agora chamado folículo domi-nante, já que sua trajetória de crescimento sofre um desvio com respeito a seguida pelo restante do grupo. Os folículos que não foram selecionados deixam de crescer e sofrem atresia já que deixam de possuir o suporte gonadotrópico de FSH, uma vez que as concentrações desse hormônio são suprimidos pela inibina e o estradiol produzidos pelo conjunto de folículos que conformam a onda folicular (figura 12), porém o folículo mais desenvolvido do grupo se converterá em dominante. A inibina atua diretamente a nível hipofisário para reduzir a secreção de FSH. Figura 12: onda folicular e relação dos níveis de FSH, estradiol e LH. Fonte: ZARCO, 2018. -/- Figura 13: Recrutamento, seleção e dominação folicular na espécie ovina e influência do FSH e LH nas fases. Fonte: SILVA, E. I. C. da, 2019. -/- A razão pela qual o folículo dominante é capaz de continuar seu desenvolvimento apesar da baixa nas concentrações de FSH é que o folículo é o único que alcançou o grau de progresso necessário para que apareçam os receptores para LH em suas células da granulosa. Esse processo permite ao folículo dominante ser estimulado pela LH, e que requeira baixas concentrações de FSH para manter seu desenvolvimento. A secreção de LH em forma de pulsos de baixa frequência (um pulso a cada quatro a seis horas), característica da fase lútea do ciclo estral; é suficiente para permitir que um folículo dominante continue crescendo por mais dias depois da sua seleção e que mais tarde mantenha-se viável durante alguns dias embora não aumentem de tamanho. Contu-do, se durante o período viável desse folículo não seja finalizada a fase lútea e não diminuam as concentrações de progesterona, o folículo terminará sofrendo atresia devido a exigência de um padrão de secreção acelerada de LH (aproximadamente um pulso por hora) durante o desenvolvimento pré-ovulatório, que somente pode ser produzido com a ausência da progesterona. Uma vez que um folículo dominante sofre atresia deixa de produzir inibina, pelo qual as concentrações de FSH podem elevar-se novamente para iniciar o recrutamento de outro grupo de folículos a partir da qual se origina uma nova onda folicular. Durante o ciclo estral de uma vaca podem gerar-se dois ou três ondas foliculares; somente em raros casos quatro. A etapa de dominância folicular da primeira onda na grande maioria dos casos não coincide com a regressão do corpo lúteo, pelo qual o primei-ro folículo dominante quase invariavelmente termina em atresia. Em algumas vacas o fo-lículo dominante da segunda onda ainda está viável quando se produz a regressão do corpo lúteo e acelera-se a secreção de LH, pelo qual esse segundo folículo dominante se converte em folículo pré-ovulatório e, ao final ovula. Em outros animais o segundo folícu-lo dominante também perde a sua viabilidade antes da regressão do corpo lúteo, por onde nesses animais se inicia uma terceira onda folicular, da qual surge o folículo que finalmen-te ovulará depois de produzir-se a regressão do corpo lúteo. Sem importar a onda em que se origine, uma vez que um folículo dominante é ex-posto a alta frequência de secreção de LH que se produz depois da regressão do corpo lúteo, aumenta ainda mais sua secreção de estradiol até que as altas concentrações desse hormônio comecem a exercer um feedback positivo para a secreção do LH. Isso provoca-rá a aceleração da frequência de secreção do LH até que os pulsos são tão frequentes que começam a ficar por cima e produzir-se o pico pré-ovulatório de LH, que é responsável pela realização da ovulação e a maturação final do ovócito. -/- •___DIFERENÇAS ENTRE ESPERMATOGÊNESE E OVOGÊNESE -/- Enquanto que na fêmea a ovogênese inicia-se durante a vida fetal, no macho a es-permatogênese começa na puberdade. Na fêmea, a partir de um ovócito primário se origi-na um óvulo; no macho, de um espermatócito primário se produzem, teoricamente, quatro espermatozoides. Outra característica interessante é que enquanto a fêmea já conta desde o nasci-mento com todos os ovócitos que necessitará na vida adulta, o macho necessitará chegar a puberdade para iniciar o desenvolvimento das células sexuais, já que ao nascer somente possui gonócitos precursores das células germinais, células de Sertoli e intersticiais. Na vida adulta de uma fêmea, o número de células germinais desaparece paulati-namente. Uma vez iniciada a espermatogênese no macho, a cada ciclo do epitélio seminí-fero as células germinais são renovadas mantendo a provisão para toda a vida reprodutiva. Na fêmea, a meiose sofre duas interrupções em seu transcurso, e no macho é ininterrupta. Figura 14: representação em diagramação comparativa do desenvolvimento da gametogênese. -/- Principais pontos abordados sobre as diferenças entre a gametogênese masculina e feminina: ❙ Na ovogênese a meiose contêm-se em duas ocasiões esperando acontecimentos externos para prosseguir. Já na espermatogênese não existe a suspensão da meiose. ❙ A espermatogênese é um processo contínuo, enquanto que a ovogênese pode completar exclusivamente um óvulo em cada ciclo estral; já que só pode ser completada por mais de um nas espécies que ovulam vários ovócitos no caso das porcas, cadelas, gatas etc. ❙ Na espermatogênese existem células de reserva que permitem a continuação du-rante toda a vida, enquanto que na ovogênese o número de ovócitos primários é limitado. A fêmea somente conta com os que nasceu, e eles não se dividem. ❙ Na espermatogênese obtém-se até 256 espermatozoides para cada espermatogo-nia que inicia o processo, enquanto que na ovogênese somente se obtém um óvulo a partir de cada ovócito primário. ❙ Durante a espermatogênese se produz uma metamorfose que transforma as es-permátides em espermatozoides. Na ovogênese não ocorre um processo análogo. ❙ Na espermatogênese, durante a meiose produzem-se quatro espermátides a partir de cada espermatócito primário. Na ovogênese se produz somente um óvulo a partir de cada ovócito primário; produz, ademais, dois corpos polares. ❙ Todos os óvulos que se produzem durante a ovogênese contém um cromossomo X, enquanto que a metade dos espermatozoides possuem um cromossomo Y e a outra metade um cromossomo X. ❙ Na espermatogênese produzem-se centenas ou dezenas de milhões de esperma-tozoides por dia, enquanto que na ovogênese se produz um ou alguns óvulos a cada ciclo estral. ❙ A espermatogênese produz gametas macroscópicos e com motilidade própria, enquanto que a ovogênese produz gametas grandes e imóveis. -/- REFERÊNCIAS BIBLIOGRÁFICAS -/- ABDEL-RAOUF, Mohammed et al. The postnatal development of the reproductive organs in bullswith special reference to puberty.(Including growth of the hypophysis and the adrenals). Acta endocrinologica, n. Suppl No. 49, 1960. ADONA, Paulo Roberto et al. Ovogênese e foliculogênese em mamíferos. Journal of Health Sciences, v. 15, n. 3, 2013. AERTS, J. M. J.; BOLS, P. E. J. Ovarian follicular dynamics: a review with emphasis on the bovine species. Part I: Folliculogenesis and pre‐antral follicle development. Reproduction in domestic animals, v. 45, n. 1, p. 171-179, 2010. AERTS, J. M. J.; BOLS, P. E. J. Ovarian follicular dynamics. A review with emphasis on the bovine species. Part II: Antral development, exogenous influence and future prospects. Reproduction in domestic animals, v. 45, n. 1, p. 180-187, 2010. ALBERTINI, David F.; CARABATSOS, Mary Jo. Comparative aspects of meiotic cell cycle control in mammals. Journal of molecular medicine, v. 76, n. 12, p. 795-799, 1998. AUSTIN, Colin Russell; SHORT, R. Reproduction in mammals. Cambridge, 1972. BAKER, T. G. Oogenesis and ovulation. In. Reproduction in Mammals I Germ Cells and Fertilization, p. 29-30, 1972. BEARDEN, Henry Joe et al. Reproducción animal aplicada. México: Manual Moderno, 1982. BIGGERS, John D.; SCHUETZ, Allen W. Oogenesis. University Park Press, 1972. BINELLI, Mario; MURPHY, Bruce D. Coordinated regulation of follicle development by germ and somatic cells. Reproduction, Fertility and Development, v. 22, n. 1, p. 1-12, 2009. CHIARINI-GARCIA, Helio; RUSSELL, Lonnie D. High-resolution light microscopic characterization of mouse spermatogonia. Biology of reproduction, v. 65, n. 4, p. 1170-1178, 2001. CHOUDARY, J. B.; GIER, H. T.; MARION, G. B. Cyclic changes in bovine vesicular follicles. Journal of animal science, v. 27, n. 2, p. 468-471, 1968. CLERMONT, Yves; PEREY, Bernard. Quantitative study of the cell population of the seminiferous tubules in immature rats. American Journal of Anatomy, v. 100, n. 2, p. 241-267, 1957. COSTA, DEILER SAMPAIO; PAULA, T. A. R. Espermatogênese em mamíferos. Scientia, v. 4, 2003. CUNNINGHAM, James. Tratado de fisiologia veterinária. Elsevier Health Sciences, 2011. CUPPS, Perry T. (Ed.). Reproduction in domestic animals. Elsevier, 1991. DA SILVA, Emanuel Isaque Cordeiro. Fisiologia Clínica do Ciclo Estral de Vacas Leiteiras: Desenvolvimento Folicular, Corpo Lúteo e Etapas do Estro. 2020. Acervo pessoal. DA SILVA, Emanuel Isaque Cordeiro. Fisiologia da Reprodução Animal: Ovulação, Controle e Sincronização do Cio. 2020. Acervo pessoal. DUKES, Henry Hugh; SWENSON, Melvin J.; REECE, William O. Dukes fisiologia dos animais domésticos. Editora Guanabara Koogan, 1996. EPIFANO, Olga; DEAN, Jurrien. Genetic control of early folliculogenesis in mice. Trends in Endocrinology & Metabolism, v. 13, n. 4, p. 169-173, 2002. ERICKSON, B. H. Development and senescence of the postnatal bovine ovary. Journal of animal science, v. 25, n. 3, p. 800-805, 1966. REFERÊNCIAS BIBLIOGRÁFICAS -/- FELDMAN, Edward C. et al. Canine and feline endocrinology-e-book. Elsevier health sciences, 2014. FUSCO, Giuseppe; MINELLI, Alessandro. The Biology of Reproduction. Cambridge University Press, 2019. GALINA-HIDALGO, Carlos Salvador. 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HYTTEL, Poul; SINOWATZ, Fred; VEJLSTED, Morten. Embriologia veterinária. São Paulo: Elsevier Brasil, 2012. JOHNSON, Martin H. Essential reproduction. Nova Jersey: John Wiley & Sons, 2018. JONES, Richard E.; LOPEZ, Kristin H. Human reproductive biology. Academic Press, 2013. KIERSZENBAUM, Abraham L.; TRES, Laura L. Primordial germ cell‐somatic cell partnership: A balancing cell signaling act. Molecular Reproduction and Development: Incorporating Gamete Research, v. 60, n. 3, p. 277-280, 2001. MATZUK, Martin M. et al. Intercellular communication in the mammalian ovary: oocytes carry the conversation. Science, v. 296, n. 5576, p. 2178-2180, 2002. MCLAREN, Anne. Germ and somatic cell lineages in the developing gonad. Molecular and cellular endocrinology, v. 163, n. 1-2, p. 3-9, 2000. MCKINNON, Angus O. et al. (Ed.). Equine reproduction. John Wiley & Sons, 2011. MERCHANT-LARIOS, Horacio; MORENO-MENDOZA, Norma. Onset of sex differentiation: dialog between genes and cells. 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Gametogénese. In. PORTA, L. R.; MEDRANO, J. H. H. Fisiología reproductiva de los animales domésticos. Cidade do México: FMVZ-UNAM, 2018. ZIRKIN, Barry R. et al. Endocrine and Paracrine Regulation of Mammalian Spermatogenesis. In: Hormones and Reproduction of Vertebrates. Academic Press, 2011. p. 45-57. -/- REALIZAÇÃO -/- . (shrink)

This is the co-authored--with Carolyn Korsmeyer--Introduction to the first published feminist scholarship in The Journal of Aesthetics and Art Criticism (Volume 48, Number 4, Fall 1990). Contributors included Hilde Hein, Paul Mattick, Jr., Timothy Gould, Joanne B. Waugh, Joseph Margolis, Mary Devereaux, Noel Carroll, Flo Leibowitz, Anita Silvers, Elizabeth Ann Dobie, Renee Cox, and Ellen Handler Spitz. All essays were subsequently published in an expanded book version entitled, Feminism and Tradition in Aesthetics by Penn State Press (1995).

For Aristotle, a verb (ῥῆμα) is that which a) besides a proper meaning b) carry with it the notion of time; c) its parts do not significate separately and d) is a sign of something said of something else (OI ., 2, 16b6-8). This comprehensive definition distinguishes verbs from both nouns (since they do not carry the notion of time with themselves) and sentences or co-positings of words (since they have parts with independent meanings). Based on this definition, a verb (...) signifies three things: i) A main or proper meaning which is the meaning of the verb, e.g. running or sleeping; ii) time and iii) co-positing (or positing away). Although it is not asserted that one part is responsible for prossignification of time, its responsibility is given to co-positing-is. This might seem to be in contradiction with (c). However, it seems that (c) cannot include prossignifications of time and co-positing. What Aristotle means in (c) is just that parts of a verb cannot separately signify a meaning. Therefore, it is better to distinguish between signification, which is about meaning and prossignification, which is generally about anything but meaning. Hence, while the parts of the verb cannot have separate signification, they can have separate prossignification. Aristotle distinguishes between different kinds of verbs: 1) Definite verbs: those verbs that have definite nouns as their verb-name. 2) Indefinite verbs: those verbs that do not have definite nouns as their verb-name (OI., I, 3, 16b12-14; 10, 19b10-11). Aristotle’s examples of an indefinite verb are ‘is not-healthy’ and ‘is not-ill’. 3) Tenses of verbs: ‘was healthy’ and ‘will be healthy’ are tenses of the verb ‘is healthy’ because a verb indicates only the present time (OI., I, 3, 16b16-18). For Aristotle, almost all verbs either are composed of or can be analyzed to parts. An example of the former is ‘is healthy’ and of the latter is ‘runs,’ which can be analyzed to two parts: ‘is running.’ (OI., I, 10, 20a3-5; II, 12, 21b5-8). Thus, for him a verb either includes or can be analyzed to two parts: a part that includes the meaning and is, or is shown, by a name we call ‘verb-name’ (a), and a part that includes the co-positing of that meaning with the subject of the verb, which is or is shown by ‘is’, which we call ‘co-positing-is’ (d). The verb ‘runs’, for example, can be analyzed to a verb-name, ‘running’ and a co-positing-is (Note: Aristotle distinguishes between the verb ‘is’ in the sense of ‘exists’ and the co-positing ‘is’. Whereas in the former ‘is’ is a verb, having a signification of its own, which is ‘existing’, besides signifying time (OI., I, 10, 19b12-19), the ‘is’ in the latter is not a verb (Aristotle calls it ‘incidental’ is (OI., II, 11, 21a25-28) and is not sure whether to call it a verb or a noun (OI., I, 10, 19b22-24)) because it does not signify existing and, thus, need something else to be added. This something else is the meaning we are discussing. Therefore, it is only after the addition of the meaning to this ‘is’ that we have a verb. This is, I believe, the sense of the so much controversial text of OI, I, 3, 16b22-25: ‘For being and not being signify the existence of a thing not τὸ ὄν εἴπῃς αὐτὸ καθ᾿ ἑαυτὸ ψιλόν. For it does not indicate anything but prossignifies some co-positing (σύνθεσίν). Aristotle’s words at 16b24 about co-positing-is that it ‘prossignifies some co-positing’ (προσσημαίνει δὲ σύνθεσίν τινα) is an explicit evidence that she cannot be right.) and is not a concept apart from the things co-posited (συγκειμένων).’ This text, however, is so controversial. Originating from Ammonius and Boethius after him, who used the verb ‘copular’ for ‘est’ and Abelard, some commentators like Weidemann, Oehler, Francisco Ademollo take ‘is’ as having a copulative function. Allen Bāck notes that Aristotle does not separate off ‘is’ from other verbs as a mere copula but takes it ‘as the basic, paradigmatic form of the verb.’ He believes that in his interpretation of Aristotle (in: OI., 55, 19-24) Ammonius also took it as the paradigm for all verbs. Francisco Ademollo criticizes the standard view of taking ‘is’ as copula here and is inclined to take it as essential. David Ross thinks that although Aristotle is aware of the distinction between the existential and the copulative is, he has as yet no very clear idea of their relation. Although Jonathan Barnes agrees that the copula is surely present in de Interpretation, he thinks that at 16b22-25 Aristotle ought to be talking of existential εἶναι. Marie De Rijk Lambartus believes that there is no copula in Aristotle’s philosophical analysis of the elementary sentences and it is a mere corpus alienum in Aristotle’s semantics. Allan Bȃck believes that the copulative theory is not Aristotle’s and ‘may have come to dominate as a result of the neoPlatonizing interpretations of Aristotle’s works by Proclus, Ammonius and Boethius, which is the sign of the relation of running with a subject, e.g. Socrates in ‘Socrates runs’. Nonetheless, none of these parts significate separately. This is supposed to mean that a verb is a single signification. However, it is evident that each of the parts can signify if we use them in a different context as both of ‘running’ and ‘is’ in ‘runs’ or both of ‘is’ and ‘healthy’ in ‘is healthy’ can do. It might seem now that the first mentioned definition of verb might be contradictory. While Aristotle asserts that the parts of verb do not signify separately (d), he considers two other significations for a verb: the signification of time and relation. As it is obvious, both of these significations are done by one part of the verb, that is the co-positing-is. Therefore, in a verb e.g. ‘is healthy’ we have three significations: the significations of meaning, time and co-positing. Aristotle uses prossignification both for time (προσσημαῖνον χρόνον, OI., 2, 16b4) and co-positing (προσσημαίνει δἑ σύνθεσὶν τινα, OI, I, 3, 16b23-24). Since the copula part of a verb has no signification and does not form any conception, a verb is indeed its verb-name. Thus we see Aristotle saying that ‘verbs are in and by themselves names and signify something’ and like names, he adds, they arrest the hearer’s mind and fix his attention (OI., I, 3, 16b19-22). We can conclude then that verbs are names said of something else and carrying time. In other words, verbs are words that though have one single signification, as names have, they also have two other prossignifications: time and relation. (shrink)

In 1982 Jackson introduced the Knowledge Argument to elucidate the phenomenal, interior aspects of experience. In 1908 McTaggart defined two series that characterize one dimension of time, the A-series and the B-series. The A-series is usually thought to be phenomenal [Farr 2019], [Dainton 2018]. Thus there is the possibility of giving a Knowledge Argument for time [Merriam 2012, 2022a]. One (informal) statement of the classical Knowledge Argument might be “Mary knows all the facts about color qualia but lives in (...) a black-and-white room. Upon being released into a colorful world, it would seem she learns something new.” The analogous Knowledge Argument for Time (KAT) would be “Nathan knows all the facts about time but lives in a B-series room. Upon being released into a world that has both an A-series and a B-series it would seem he learns something new.” I give variations of the KAT based on various distinctions. I don’t give any particular proposed solutions to the Knowledge Arguments for Time. Rather, the point is to state the Arguments (or indicate how they may be stated). It may be hoped that these will help clarify some issues in the philosophy of time and lead to a cross-fertilization between the philosophy of time and the philosophy of mind. (shrink)

In Byron, Shelley, and Goethe’s Faust, author Ben Hewitt has provided us with a carefully done and convincing study. Given this, it would have been interesting to see Hewitt’s effort to integrate Mary Shelley’s work into his narrative. Apart from any similarities between Faust and Frankenstein, it bears remembering that Goethe himself remained unconvinced by efforts to clearly demarcate works as “tragic” or “epic”; a fact that becomes especially clear in the number of works he’d devoted to rewriting the (...) story of Prometheus. One cannot help but wish that Hewitt had considered the connection between these works and Shelley’s own “Modern Prometheus” in juxtaposition to his reading of P.B. Shelley’s Prometheus Unbound, for this would have made for an especially good ending to Hewitt’s story. Wayne Deakin’s consideration of Hegel and the English Romantic Tradition does indeed close with a brief consideration of Mary Shelley’s Prometheus, but this comes only at the end of a much longer set of considerations. In this book Deakin adopts a similar strategy as that of Hewitt, namely, foregoing any historical recovery of Hegel’s direct influence on the English Romantics—in Deakin’s case, Coleridge, Wordsworth, and P.B. Shelley—to focus instead on a reading of key poetic works in concert with their Hegelian framework. This reading essentially flows from Deakin’s effort to rethink Hegel’s relatively early notion of self-consciousness through his late lectures on aesthetics. For Deakin, this leads to “aesthetic recognition”; a situating of the self in relation to the world that remains in tension so far as the subject’s drive for autonomy will automatically be humbled by its reception of and to alterity—be that other “Nature” or other subject. (shrink)

With an eye on the future of global ethics, I argue that social-media technologies are not morally neutral tools but are, for all intents and purposes, a kind of agent. They nudge us to do things that are bad for us. Moreover, I argue that we have a duty to quit using social-media platforms, not just on account of possible duties to preserve our own well-being but because users are akin to test subjects on whom developers are testing new nudges, (...) and we ought to deprive them of their test subjects. (shrink)

This paper identifies, develops, and argues for an interpretation of Mary Astell’s understanding of self-government. On this interpretation, what is essential to self-government, according to Astell, is an agent’s responsiveness to her own reasoning. The paper identifies two aspects of her theory of self-government: an ‘authenticity’ criterion of what makes our motives our own and an account of the capacities required for responsiveness to our own reasoning. The authenticity criterion states that when our motives arise from some external source (...) without validation by our own understanding of the reasons supporting them, then they are not our own. The capacities requisite for responsiveness to our own reasoning are those of examining and evaluating our own motives and of resisting the social pressure to conform to others’ opinions. An upshot of this interpretation of Astell’s theory of self-government is that it reveals her insights into the ways ‘custom’ can undermine an individual’s ability to govern oneself. (shrink)

In this article, I argue that online echo chambers are in some cases and in some respects good. I do not attempt to refute arguments that they are harmful, but I argue that they are sometimes beneficial. In the first section, I argue that it is sometimes good to be insulated from views with which one disagrees. In the second section, I argue that the software-design principles that give rise to online echo chambers have a lot to recommend them. Further, (...) the opposing principle, serendipity, could give rise to serious harm, in light of the conclusion of the first section that sometimes we are better off being insulated from some content online. In the third section, I argue that polarization can be a useful tool for inculcating the appropriate attitudes in a person. (shrink)

I argue that Plato believes that the soul must be both the principle of motion and the subject of cognition because it moves things specifically by means of its thoughts. I begin by arguing that the soul moves things by means of such acts as examination and deliberation, and that this view is developed in response to Anaxagoras. I then argue that every kind of soul enjoys a kind of cognition, with even plant souls having a form of Aristotelian discrimination (...) (krisis), and that there is therefore no completely unintelligent, evil soul in the cosmos that can explain disorderly motions; as a result, the soul is not the principle of all motion but only motion in the cosmos after it has been ordered by the Demiurge. (shrink)

I argue that, according to Plato, the body is the sole cause of psychic disorders. This view is expressed at Timaeus 86b in an ambiguous sentence that has been widely misunderstood by translators and commentators. The goal of this article is to offer a new understanding of Plato’s text and view. In the first section, I argue that although the body is the result of the gods’ best efforts, their sub-optimal materials meant that the soul is constantly vulnerable to the (...) body’s influences. In the second section, I argue that every psychic disorder is a disruption of the motions of the inner psychic circles by the body; moreover, I defend my translation of 86b. In the final section, I argue that the goal of education is to restore the circles to their original orbits, and I disarm a possible objection that bad education is also a cause of psychic disorder. (shrink)

This article concerns the place of Plato’s eschatology in his philosophy. I argue that the theory of reincarnation appeals to Plato due to its power to explain how non-human animals came to be. Further, the outlines of this theory are entailed by other commitments, such as that embodiment disrupts psychic functioning, that virtue is always rewarded and vice punished, and that the soul is immortal. I conclude by arguing that Plato develops a view of reincarnation as the chief tool that (...) the gods have to ensure that virtue is victorious over vice throughout the whole cosmos. (shrink)

In what follows I offer some reflections on an ethics of listening, or perhaps more generally a philosophy of listening, that can be discerned in different forms in the experimental music that, since the 1950s, has challenged and radicalised how music is understood. I situate these reflections around three of my own concert experiences as an audience member.

Where does agency lie in musical performance? How is it expressed? Recent music scholarship has highlighted an increasingly prominent tendency to conceive of agency as not confined to any one individual or type of individual, instead being distributed across diverse individuals that can be found occupying performance situations. . This article uses two ‘percussion’ works from the 1970s by the composer John Cage, Child of Tree (1975) and its multi-performer elaboration Branches (1976), as a foil for engaging with these practical (...) and theoretical musical concerns, and for suggesting some heretofore underappreciated distinctions within the ongoing work on multi-agential performance. (shrink)

This article is featured in a special issue dedicated to theme, "the human being in the digital era: awareness, critical thinking and political space in the age of the internet and artificial intelligence." In this article, I consider the way that social-media companies nudge us to spend more time on their platforms, and I argue that, in principle, these nudges are morally permissible: they are not manipulative and do not violate any obvious moral rules. The moral problem, I argue, is (...) not with nudging in principle but is instead with the fact that users are being nudged towards something bad for them. In practice, this often involves being nudged to spend an unhealthy amount of time using a social-media app or being nudged towards content that is bad for us, such as by promoting eating-disorder content to young girls. Since nudging is morally permissible, it is open to these companies to use the same technologies to nudge us towards the good. (shrink)

In this article, I approach some phenomena seen predominantly on social-media sites that are grouped together as cancel culture with guidance from two major themes in Plato’s thought. In the first section, I argue that shame can play a constructive and valuable role in a person’s improvement, just as we see Socrates throughout Plato’s dialogues use shame to help his interlocutors improve. This insight can help us understand the value of shaming people online for, among other things, their morally reprehensible (...) views. In the second section, I argue that it is required for the proper functioning of democratic institutions that some views be excluded from the public sphere, which follows some Platonic ideas from the Laws. In neither case do I argue that this approach is good in an unqualified sense or even ultima facie good. However, I maintain that these important insights from Plato’s dialogues illuminate crucial aspects of how we should think about cancel culture. (shrink)

This paper concerns Plato’s characterization of the body as the soul’s tool. I take perception as an example of the body’s usefulness. I explore the Timaeus’ view that perception provides us with models of orderliness. Then, I argue that perception of confusing sensible objects is necessary for our cognitive development too. Lastly, I consider the instrumentality relationship more generally and its place in Plato’s teleological worldview.

In this article, I make the case for the continued relevance of Plato’s Timaeus. I begin by sketching Allan Bloom’s picture of the natural sciences today in The Closing of the American Mind, according to which the natural sciences are, objectionably, increasingly specialized and have ejected humans qua humans from their purview. I argue that Plato’s Timaeus, despite the falsity of virtually all of its scientific claims, provides a model for how we can pursue scientific questions in a comprehensive way (...) that stresses their connections to other disciplines, including the humanities, and that puts humanity qua humanity back in the picture. I then argue that being led by Plato’s philosophy to return humanity conceptually to the natural world can improve our thinking regarding climate change and other important environmental crises. (shrink)

I argue that Plato thinks that the soul has location, surface, depth, and extension, and that the Timaeus’ composition of the soul out of eight circles is intended literally. A novel contribution is the development of an account of corporeality that denies the entailment that the soul is corporeal. I conclude by examining Aristotle’s objection to the Timaeus’ psychology and then the intellectual history of this reading of Plato.