Natural/social kind essentialism is the view that natural kind categories, both living and non-living natural kinds, as well as social kinds (e.g., race, gender), are essentialized. On this view, artifactual kinds are not essentialized. Our view—teleological essentialism—is that a broad range of categories are essentialized in terms of teleology, including artifacts. Utilizing the same kinds of experiments typically used to provide evidence of essentialist thinking—involving superficial change (study 1), transformation of insides (study 2) and inferences about offspring (study 3)—we find (...) support for the view that a broad range of categories—living natural kinds, non-living natural kinds and artifactual kinds—are essentialized in terms of teleology. Study 4 tests a unique prediction of teleological essentialism and also provides evidence that people make inferences about purposes which in turn guide categorization judgments. (shrink)

von Fintel and Gillies : 329–360, 2007) have proposed a dynamic strict conditional account of counterfactuals as an alternative to the standard variably strict account due to Stalnaker and Lewis. Von Fintel’s view is motivated largely by so-called reverse Sobel sequences, about which the standard view seems to make the wrong predictions. More recently Moss :561–586, 2012) has offered a pragmatic/epistemic explanation that purports to explain the data without requiring abandonment of the standard view. So far the small amount of (...) subsequent literature has focused primarily on the original class of cases motivating the strict conditional view. What is needed in the debate is an examination of the predictions of the dynamic strict conditional account for a broader range of data. I undertake this task here, presenting a slew of cases that are problematic for the strict conditional view but not for Moss’s view, and considering some possible responses. Ultimately I take my contribution to constitute a significant blow to the dynamic strict conditional view, though not a decisive verdict against it. (shrink)

This article revisits, analyzes and critiques Bruce Chatwin’s 1987 bestseller, The Songlines,1 more than three decades after its publication. In Songlines, the book primarily responsible for his posthumous celebrity, Chatwin set out to explore the essence of Central and Western Desert Aboriginal Australians’ philosophical beliefs. For many readers globally, Songlines is regarded as a—if not the—definitive entry into the epistemological basis, religion, cosmology and lifeways of classical Western and Central Desert Aboriginal people. It is argued that Chatwin’s fuzzy, ill-defined use (...) of the word-concept “songlines”2 has had the effect of generating more heat than light. Chatwin’s failure to recognize the economic imperative underpinning Australian desert people’s walking praxis is problematic: his own treks through foreign lands were underpropped by socioeconomic privilege. Chatwin’s ethnocentric idée fixe regarding the primacy of “walking” and “nomadism,” central to his Songlines thématique, well and truly preceded his visits to Central Australia. Walking, proclaimed Chatwin, is an elemental part of “Man’s” innate nature. It is argued that this unwavering, preconceived, essentialist belief was a self-serving construal justifying Chatwin’s own “nomadic” adventures of identity. Is it thus reasonable to regard Chatwin as a “rogue author,” an unreliable narrator? And if so, does this matter? Of greatest concern is the book’s continuing majority acceptance as a measured, accurate account of Aboriginal belief systems. With respect to Aboriginal desert people and the barely disguised individuals depicted in Songlines, is Chatwin’s book a “rogue text,” constituting an act of epistemic violence, consistent with Spivak’s usage of that term? (shrink)

This essay discusses Cecilia Heyes’ groundbreaking new book Cognitive Gadgets: The Cultural Evolution of Thinking. Heyes’ point of departure is the claim that current theories of cultural evolution fail adequately to make a place for the mind. Heyes articulates a cognitive psychology of cultural evolution by explaining how eponymous “cognitive gadgets,” such as imitation, mindreading and language, mental technologies, are “tuned” and “assembled” through social interaction and cultural learning. After recapitulating her explanations for the cultural and psychological origins of these (...) gadgets, we turn to criticisms. Among those, we find Heyes’ use of evolutionary theory confusing on several points of importance; alternative theories of cultural evolution, especially those of the Tomasello group and of Boyd, Richerson and Henrich, are misrepresented; the book neglects joint attention and other forms of intersubjectivity in its explanation of the origins of cognitive gadgets; and, whereas Heyes accuses other theories of being “mindblind,” we find her theory ironically other-blind and autistic in character. (shrink)

Placeholder essentialism is the view that there is a causal essence that holds category members together, though we may not know what the essence is. Sometimes the placeholder can be filled in by scientific essences, such as when we acquire scientific knowledge that the atomic weight of gold is 79. We challenge the view that placeholders are elaborated by scientific essences. On our view, if placeholders are elaborated, they are elaborated Aristotelian essences, a telos. Utilizing the same kinds of experiments (...) used by traditional essentialists—involving superficial change (study 1), transformation of insides (study 2), acquired traits (study 3) and inferences about offspring (study 4)—we find support for the view that essences are elaborated by a telos. And we find evidence (study 5) that teleological essences may generate category judgments. (shrink)

In this paper, I present my solutions to two closely related questions about pleasure. One of these questions is fairly well known. The second question seems to me to be at least as interesting as the first, but it apparently hasn't interested quite so many philosophers.

ABSTRACT Drawing inspiration from Fred Dretske, L. S. Carrier, John A. Barker, and Robert Nozick, we develop a tracking analysis of knowing according to which a true belief constitutes knowledge if and only if it is based on reasons that are sensitive to the fact that makes it true, that is, reasons that wouldn’t obtain if the belief weren’t true. We show that our sensitivity analysis handles numerous Gettier-type cases and lottery problems, blocks pathways leading to skepticism, and validates (...) the epistemic closure thesis that correct inferences from known premises yield knowledge of the conclusions. We discuss the plausible views of Ted Warfield and Branden Fitelson regarding cases of knowledge acquired via inference from false premises, and we show how our sensitivity analysis can account for such cases. We present arguments designed to discredit putative counterexamples to sensitivity analyses recently proffered by Tristan Haze, John Williams and Neil Sinhababu, which involve true statements made by untrustworthy informants and strange clocks that sometimes display the correct time while running backwards. Finally, we show that in virtue of employing the paradox-free subjunctive conditionals codified by Relevance Logic theorists instead of the paradox-laden subjunctive conditionals codified by Robert Stalnaker and David Lewis. (shrink)

To say Early Confucians advocated the possession of a sense of shame as a means to moral virtue underestimates the tact and forethought they used successfully to mold natural dispositions to experience shame into a system of self, familial, and social governance. Shame represents an adaptive system of emotion, cognition, perception, and behavior in social primates for measurement of social rank. Early Confucians understood the utility of the shame system for promotion of cooperation, and they build and deploy cultural modules (...) – e.g., rituals, titles, punishments – with this in mind. These policies result in subtle alterations to components of the evolved shame system that are detectable in data form contemporary cross-cultural psychology that show that populations in the Confucian diaspora have a unique shame profile compared to Western and non-Western populations. The status of Confucian diaspora populations as outliers in the context of shame is partially explained by appeal to the cultural transmission and historical endurance of relevant Early Confucian cultural modules. (shrink)

Embodied cognition is sweeping the planet. On a non-embodied approach, the sensory system informs the cognitive system and the motor system does the cognitive system’s bidding. There are causal relations between the systems but the sensory and motor systems are not constitutive of cognition. For embodied views, the relation to the sensori-motor system to cognition is constitutive, not just causal. This paper examines some recent empirical evidence used to support the view that cognition is embodied and raises questions about some (...) of the claims being made by supporters. (shrink)

Philosophical interest in situated cognition has been focused most intensely on the claim that human cognitive processes extend from the brain into the tools humans use. As we see it, this radical hypothesis is sustained by two kinds of mistakes, the confusion of coupling relations with constitutive relations and an inattention to the mark of the cognitive. Here we wish to draw attention to these mistakes and show just how pervasive they are. That is, for all that the radical philosophers (...) have said, the mind is still in the head. (shrink)

Assume for the sake of argument that doing philosophy is intrinsically valuable, where ‘doing philosophy’ refers to the practice of forging arguments for and against the truth of theses in the domains of metaphysics, epistemology, ethics, etc. The practice of the history of philosophy is devoted instead to discovering arguments for and against the truth of ‘authorial’ propositions, i.e. propositions that state the belief of some historical figure about a philosophical proposition. I explore arguments to think that doing history of (...) philosophy is valuable, specifically, valuable in such a way that its value does not reduce to the value of doing philosophy. Most such arguments proffered by historians of philosophy fail egregiously, as I show. I then offer a proposal about what makes doing history of philosophy uniquely valuable, but it is one that many historians will not find agreeable. (shrink)

In a recent very interesting and important challenge to tracking theories of knowledge, Williams & Sinhababu claim to have devised a counter-example to tracking theories of knowledge of a sort that escapes the defense of those theories by Adams & Clarke. In this paper we will explain why this is not true. Tracking theories are not undermined by the example of the backward clock, as interesting as the case is.

There has been much interest in conspiracy theories (CTs) amongst philosophers in recent years. The aim of this paper will be to apply some of the philosophical research to issues in political theory. I will first provide an overview of some of the philosophical discussions about CTs. While acknowledging that particularism is currently the dominant position in the literature, I will contend that the ‘undue scepticism problem’, a modified version of an argument put forward by Brian Keeley, is an important (...) general objection to many CTs. This in turn leads to some substantial conclusions for liberal political philosophy, as the undue scepticism problem sets up a strong argument against non-liberal alternatives to liberal thought. I shall argue that we are justified in having far more doubt about the reliability of official sources in non-liberal societies, and it is legitimate to be more sceptical about claims designed to bolster non-liberal politics. Moreover, because scepticism is often more warranted in non-liberal societies, this may provide the possibility for the state to be stable, even if it is highly tyrannical or ineffective. These considerations are not intended to be decisive, but raise unresolved questions about the viability of non-liberal politics. (shrink)

Memory of past episodes provides a sense of personal identity — the sense that I am the same person as someone in the past. We present a neurological case study of a patient who has accurate memories of scenes from his past, but for whom the memories lack the sense of mineness. On the basis of this case study, we propose that the sense of identity derives from two components, one delivering the content of the memory and the other generating (...) the sense of mineness. We argue that this new model of the sense of identity has implications for debates about quasi-memory. In addition, articulating the components of the sense of identity promises to bear on the extent to which this sense of identity provides evidence of personal identity. (shrink)

Fred's semantics for McCall's syntactic presentation of Aristotle's assertoric and apodeictic syllogistic is altered to free it from Thom's objections that it is unAristotelian. The altered semantics rejects Baroco-XLL and Bocardo-LXL, which Thom says Aristotle should have accepted. Aristotle's proofs that use ecthesis are formalized by using singular sentences. With one exception the (acceptance) axioms for McCall's system L-X-M are derivable. Formal proofs are shown to be sound.

In a recent paper, Tristan Haze offers two examples that, he claims, are counterexamples to Nozick's Theory of Knowledge. Haze claims his examples work against Nozick's theory understood as relativized to belief forming methods M. We believe that they fail to be counterexamples to Nozick's theory. Since he aims the examples at tracking theories generally, we will also explain why they are not counterexamples to Dretske's Conclusive Reasons Theory of Knowledge.

In this article, we will describe higher order thought theories of consciousness. Then we will describe some examples from synesthesia. Finally, we will explain why the latter may be relevant to the former.

Many philosophers maintain that causation is to be explicated in terms of a kind of dependence between cause and effect. These “dependence” theories are opposed by “production” accounts which hold that there is some more fundamental causal “oomph”. A wide range of experimental research on everyday causal judgments seems to indicate that ordinary people operate primarily with a dependence-based notion of causation. For example, people tend to say that absences and double preventers are causes. We argue that the impression that (...) commonsense causal discourse is largely dependence-based is the result of focusing on a very narrow class of causal verbs. Almost all of the vignette-based experimental work on causal judgment has been prosecuted using the word “cause”. But much ordinary causal discourse involves special causal verbs, such as “burn” and “crack”. We find that these verbs display a quite different pattern from the verb “cause”. For instance, for absences and double preventers (Studies 1-3), we find that while people are inclined to say that X caused Y to burn, turn, crack or start, they are less inclined to think that X burned, turned, cracked or started Y. In Study 4, we find that for chains involving a distal and proximal event, people are inclined to say that the distal event is not a special cause of the outcome, though it is a “cause” of the outcome. Together, we find a surprising double dissociation between “cause” and a stock of special causal verbs. We conclude by suggesting that much commonsense causal judgment, which heavily trades in special causal verbs, might be better captured by production-based accounts of causation. (shrink)

Fred shows how problems with Slater's restriction of the classical propositional logic can be solved.

This book consists of an edited collection of original essays of the highest academic quality by seasoned experts in their fields of cognitive science. The essays are interdisciplinary, drawing from many of the fields known collectively as “the cognitive sciences.” Topics discussed represent a significant cross-section of the most current and interesting issues in cognitive science. Specific topics include matters regarding machine learning and cognitive architecture, the nature of cognitive content, the relationship of information to cognition, the role of language (...) and communication in cognition, the nature of embodied cognition, selective topics in visual cognition, brain connectivity, computation and simulation, social and technological issues within the cognitive sciences, and significant issues in the history of neuroscience. This book will be of interest to both professional researchers and newer students and graduate students in the fields of cognitive science—including computer science, linguistics, philosophy, psychology and neuroscience. The essays are in English and are designed to be as free as possible of technical jargon and therefore accessible to young scholars and to scholars who are new to the cognitive neurosciences. In addition to several entries by single authors, the book contains several interesting roundtables where researchers contribute answers to a central question presented to those in the focus group on one of the core areas listed above. This exciting approach provides a variety of perspectives from across disciplines on topics of current concern in the cognitive sciences. (shrink)

The idea that incompatibilism is intuitive is one of the key motivators for incompatibilism. Not surprisingly, then philosophers who defend incompatibilism often claim that incompatibilism is the natural, commonsense view about free will and moral responsibility (e.g., Pereboom 2001, Kane Journal of Philosophy 96:217–240 1999, Strawson 1986). And a number of recent studies find that people give apparently incompatibilist responses in vignette studies. When participants are presented with a description of a causal deterministic universe, they tend to deny that people (...) are morally responsible in that universe. Although this suggests that people are intuitive incompatibilists, Eddy Nahmias and Dylan Murray, in a recent series of important papers, have developed an important challenge to this interpretation. They argue that people confuse determinism with bypassing, the idea that one’s mental states lack causal efficacy. Murray and Nahmias present new experiments that seem to confirm the bypassing hypothesis. In this paper, we use structural equation modeling to re-examine the issue. We find support instead for an incompatibilist explanation of the bypassing results, i.e., incompatibilist judgments seem to cause bypassing judgments. We hypothesize that this phenomenon occurs because people think of decisions as essentially indeterministic; thus, when confronted with a description of determinism they tend to think that decisions do not even occur. We provide evidence for this in three subsequent studies which show that many participants deny that people make decisions in a deterministic universe; by contrast, most participants tend to allow that people add numbers in a deterministic universe. Together, these studies suggest that bypassing results don’t reflect a confusion, but rather the depth of the incompatibilist intuition. (shrink)

Parry discusses an extension of Aristotle's syllogistic that uses four nontraditional quantifiers. We show that his conjectured decision procedure for validity for the extended syllogistic is correct even if syllogisms have more than two premises. And we axiomatize this extension of the syllogistic.

Tristan Haze claims we have made two mistakes in replying to his two attempted counter-examples to Tracking Theories of Knowledge. Here we respond to his two recent claims that we have made mistakes in our reply. We deny both of his claims.

A semantics is presented for Storrs McCall's separate axiomatizations of Aristotle's accepted and rejected polysyllogisms. The polysyllogisms under discussion are made up of either assertoric or apodeictic propositions. The semantics is given by associating a property with a pair of sets: one set consists of things having the property essentially and the other of things having it accidentally. A completeness proof and a semantic decision procedure are given.

A tradition of work in cognitive science indicates that much of our mental lives is not available to introspection . Though the researchers often present these results as surprising, little has been done to explore the degree to which people presume introspective access to their mental events. In this paper, we distinguish two dimensions of introspective access: the power of access, i.e. whether people believe they can unfailingly or only typically introspect mental events; and the domain of access, i.e. what (...) types of mental events people believe they are able to introspect. We report five experiments carried out to discover where lay beliefs about introspection fall on these dimensions. In our experiments, people did not presume universal introspective access, but they did overestimate the amount of access they actually have, particularly in the case of decisions. (shrink)

Consequence rleations over sets of "judgments" are defined by using "overdetermined" as well as "underdetermined" valuations. Some of these relations are shown to be categorical. And generalized soundness and completeness results are given for both multiple and single conclusion consequence relations.

Many philosophers have claimed that the folk endorse moral universalism. Some have taken the folk view to support moral universalism; others have taken the folk view to reflect a deep confusion. And while some empirical evidence supports the claim that the folk endorse moral universalism, this work has uncovered intra-domain differences in folk judgments of moral universalism. In light of all this, our question is: why do the folk endorse moral universalism? Our hypothesis is that folk judgments of moral universalism (...) are generated in part by a desire to punish. We present evidence supporting this across three studies. On the basis of this, we argue for a debunking explanation of folk judgments of moral universalism. Our results not only further our understanding of the psychological processes underpinning folk judgments of moral universalism. They also bear on philosophical discussions of folk meta-ethics. (shrink)

John Rawls’ A Theory of Justice allows social facts behind his veil-of-ignorance, thereby lessening the veil’s capacity for neutrality and defense of liberal principles. Rawls assumes social facts are discoverable without presupposed political values. But even if value-neutral social science is possible, real-world opinions, defined by political/social world-views, open the veil to bias since social facts from a non-liberal view may bolster non-liberal programmes. Alternatively, depriving those behind the veil of knowledge of social facts strips them of vital information necessary (...) for creating a just, well-organized society. These reservations do not constitute decisive criticisms but point out unresolved tension in Rawls’ original position, and the veil’s status of neutrality is undermined. (shrink)

The paper shows that for any invalid polysyllogism there is a procedure for constructing a model with a domain with exactly three members and an interpretation that assigns non-empty, non-universal subsets of the domain to terms such that the model invalidates the polysyllogism.

McCall's system for contingent syllogisms is modified. A semantics for the resulting system is provided.

In the 17th century, Hobbes stated that we reason by addition and subtraction. Historians of logic note that Hobbes thought of reasoning as “a ‘species of computation’” but point out that “his writing contains in fact no attempt to work out such a project.” Though Leibniz mentions the plus/minus character of the positive and negative copulas, neither he nor Hobbes say anything about a plus/minus character of other common logical words that drive our deductive judgments, words like ‘some’, ‘all’, ‘if’, (...) and ‘and’, each of which actually turns out to have an oppositive, character that allows us, “in our silent reasoning,” to ignore its literal meaning and to reckon with it as one reckons with a plus or a minus operator in elementary algebra or arithmetic. These ‘logical constants’ of natural language figure crucially in our everyday reasoning. Because Hobbes and Leibniz did not identify them as the plus and minus words we reason with, their insight into what goes on in ‘ratiocination’ did not provide a guide for a research program that could develop a +/- logic that actually describes how we reason deductively. I will argue that such a +/- logic provides a way back from modern predicate logic—the logic of quantifiers and bound variables that is now ‘standard logic’—to an Aristotelian term logic of natural language that had been the millennial standard logic. (shrink)

How do people think about the mental states of robots? Experimental philosophers have developed various models aiming to specify the factors that drive people's attributions of mental states to robots. Here we report on a new experiment involving robots, the results of which tell against competing models. We advocate a view on which attributions of mental states to robots are driven by the same dual-process architecture that subserves attributions of mental states more generally. In support of this view, we leverage (...) recent psychological research on human-robot interaction that involve ecologically-valid stimuli such as Roombas and humanoid robots. (shrink)

In recent decades, postmodernists and sociologists of science have argued that science is just one of many human activities with social and political aims -- comparable to, say, religion or art. They have questioned the objectivity of science, and whether it has any unique ability to find the truth. Not surprisingly, such claims have evoked a negative response from proponents of the traditional view of science; the debate between the two sides has been called the science wars. In the debate, (...) scientists have made few attempts to meet the postmodern critique on its own grounds, through serious reflection on the everyday practice of science. Yet that is the only way to understand the nature of science and the features that distinguish science from other activities. (shrink)

Investigations into inter-level relations in computer science, biology and psychology call for an *empirical* turn in the philosophy of mind. Rather than concentrate on *a priori* discussions of inter-level relations between 'completed' sciences, a case is made for the actual study of the way inter-level relations grow out of the developing sciences. Thus, philosophical inquiries will be made more relevant to the sciences, and, more importantly, philosophical accounts of inter-level relations will be testable by confronting them with what really happens (...) in science. Hence, close observation of the ever-changing reduction relations in the developing sciences, and revision of philosophical positions based on these empirical observations, may, in the long run, be more conducive to an adequate understanding of inter-level relations than a traditional *a priori* approach. (shrink)

If you start taking courses in contemporary cognitive science, you will soon encounter a particular picture of the human mind. This picture says that the mind is a lot like a computer. Specifically, the mind is made up of certain states and certain processes. These states and processes interact, in accordance with certain general rules, to generate specific behaviors. If you want to know how those states and processes got there in the first place, the only answer is that they (...) arose through the interaction of other states and processes, which arose from others... until, ultimately, the chain goes back to factors in our genes and our environment. Hence, one can explain human behavior just by positing a collection of mental states and psychological processes and discussing the ways in which these states and processes interact. This picture of the mind sometimes leaves people feeling deeply uncomfortable. They find themselves thinking something like: 'If the mind actually does work like that, it seems like we could never truly be morally responsible for anything we did. After all, we would never be free to choose any behavior other than the one we actually performed. Our behaviors would just follow inevitably from certain facts about the configuration of the states and processes within us.' Many philosophers think that this sort of discomfort is fundamentally confused or wrongheaded. They think that the confusion here can be cleared up just by saying something like: 'Wait! It doesn't make any sense to say that the interaction of these states and processes is preventing you from controlling your own life. The thing you are forgetting is that the interaction of these states and processes – this whole complex system described by cognitive science – is simply you. So when you learn that these states and processes control your behavior, all you are learning is that you are controlling your behavior. There is no reason at all to see these discoveries as a threat to your freedom or responsibility.'2 Philosophers may regard this argument as a powerful one, perhaps even irrefutable.. (shrink)

Both autonomy and agency play central roles in the emerging enactive vocabulary. Although some treat these concepts as practically synonymous, others have sought to be more explicit about the conditions required for agency over and above autonomy. I attempt to be self-conscious about the role of the observer (or scientist) in such discussions, and emphasise that the concept of agency, in particular, is deeply entwined with the nature of the observer and the framing of the observation. This is probably well (...) known to enactivists, but runs the risk of being badly misunderstood if it is not made explicit. A heightened awareness of the role of the observer in the attribution of agency may allow us to make advances in questions in which progress is hindered by assuming a single split between subject and object. I argue that human experience is characterized by our embedding in webs of meaning arising from our participation in systems of many sorts, and that this richness demands a corresponding lightness of touch with respect to the identification of agentive subjects. (shrink)

The epistemological situation of a single cell is considered. In chemotaxis, the relation between perception and action is found to be lawful and bidirectional. Consideration of the perception/action relation allows a characterization of the phe- nomenal world of the cell. This phenomenal world is grounded in perceptual distinctions that are relevant to the sustained vi- ability of the cell. Moving up the phylogenetic chain, this lawfulness, and its relation to the phenomenal world of ex- perience, is found to be essentially (...) unchanged in multicellular organisms. Nervous systems add some innovation, in allow- ing distal responses and the non-linear combination of infor- mation, but from cell to human, the differentiation of the phe- nomenal world is found to arise from the lawfulness of the perception/action relation, which in turn reflects the biologi- cal constitution of the organism, and not a pre-given objec- tive world. This recognition suggests that rather than looking within the nervous system for representations of pre-given, ex- ternal, entities, one might do better to explore the fit between the function of the nervous system and the phenomenal, mean- ingful, world encountered by the organism in experience. (shrink)

Vows play a central role in Buddhist thought and practice. Monastics are obliged to know and conform to hundreds of vows. Although it is widely recognized that vows are important for guiding practitioners on the path to enlightenment, we argue that they have another overlooked but equally crucial role to play. A second function of the vows, we argue, is to facilitate group harmony and cohesion to ensure the perpetuation of the dhamma and the saṅgha. However, the prominence of vows (...) in the Buddhist tradition seems at odds with another central part of the doctrine. For vows, like other promises, seem to involve representing a persisting self as the individual who undertakes the vow. And to explicitly appeal to a persisting self conflicts with one of the most important philosophical commitments of Buddhism – the no self view. We argue though that once we articulate the details of how vows generate behavior that conforms to them, we can see that no appeal to the self is required to internalize and act on vows. (shrink)

Aristotle's syllogistic is extended to include denumerably many quantifiers such as 'more than 2/3' and 'exactly 2/3.' Syntactic and semantic decision procedures determine the validity, or invalidity, of syllogisms with any finite number of premises. One of the syntactic procedures uses a natural deduction account of deducibility, which is sound and complete. The semantics for the system is non-classical since sentences may be assigned a value other than true or false. Results about symmetric systems are given. And reasons are given (...) for claiming that syllogistic validity is relevant validity. (shrink)

One semantic and two syntactic decision procedures are given for determining the validity of Aristotelian assertoric and apodeictic syllogisms. Results are obtained by using the Aristotelian deductions that necessarily have an even number of premises.