Johannes Steuchius’ disputatio uses Arabic logic to present an historical account of the development of philosophical thought in Arabia before and after the emergence of Islam. Steuchius first proposes that philosophy drew its origins from the East. His evidence for this claim is that many of the Greek philosophers, considered the forefathers of European philosophy, began cultivating their philosophical thinking as a result of exposure to ancient Eastern philosophy. After the introduction of Greek philosophy, it is agreed that (...) dialectic was among the first of the arts the Arabs practiced. (shrink)

Rozprawa podkreśla związek między językową argumentacją a logiką. Argumentacja językowa jest systemem językowym, który stosuje znaczenie wyrażeń ujętych w zdania do zarysowania pełnego znaczenia zdań, w nich bowiem konstytuują się zależności między wyrażeniami. Rzeczywiście, to powiązanie między wyrażeniami wzmacnia całościowe znaczenie począwszy od samych podstaw struktury zdania w logicznym powiązaniu idei. W nim znajduje się relacja między słowami a umysłem, zależna od logiki powiązanych ze sobą wypowiedzi. Aby podkreślić znaczenie przedstawionego wyżej sposobu myślenia, autorka zwraca się ku teorii wczesnej gramatyki (...) arabskiej, ogniskującej się raczej wokół analogii niż anomalii. Nastawienie w systemie na analogię opiera się na podstawowej teorii, która implikuje wspomnianą wyżej relację, choć niektóre współczesne ujęcia odrzucają tę interpretację. W podsumowaniu swojej analizy, autorka uwzględnia podobne teorie gramatyki łacińskiej, które wykazują nastawienie logiczne, będące następstwem powiązania językowej argumentacji z logiką. Konkludując, autorka stwierdza, iż powiązanie słów i logiki okazuje się pojęciem uniwersalnym. (shrink)

The passionate and staunch defence of logic of the controversial thinker Ibn Ḥazm, Abū Muḥammad ʿAlī b. Aḥmad b. Saʿīd of Córdoba (384-456/994-1064), had lasting consequences in the Islamic world. Indeed, his book Facilitating the Understanding of the Rules of Logic and Introduction Thereto, with Common Expressions and Juristic Examples (Kitāb al-Taqrīb li-ḥadd al-manṭiq wa-l-mudkhal ilayhi bi-l-alfāẓ al-ʿāmmiyya wa-l-amthila al-fiqhiyya), composed in 1025-1029, was well known and discussed during and after his time; and it paved the way for (...) the studies of his compatriots Ibn Bājjah (d. 1138), Ibn Ṭufayl (1185), and Ibn Rushd (1198), who each gave demonstrative reasoning a privileged place within the methods of attaining knowledge. Unfortunately, as too often in the history of science, Ibn Ḥazm’s innovative perspectives and contributions in logic have been overlooked or considered with an attitude of contempt. On the one hand, his work has been seen, at best, as promulgating the benefits of studying Aristotle’s logic, so that his contribution is assessed as more didactical than conceptual. And on the other hand, those who do examine his innovations often consider them to be mistaken. As indicated by Chejne (1984, p. 2) contempt towards the logical work of Ibn Ḥazm was also present in its reception by the Eastern philosophers who accused him of deviating from Aristotelian logic and of dabbling in things beyond his capability. However, a reassessment of his work on logic has since begun, by delving into the ways the thinker of Córdoba studied the links between deontic and modal qualification of propositions. In this context Lameer’s (2013) paper on the logical sources of Ibn Ḥazm is worth mentioning; the author (p. 417, footnote 1) observes that, although, strictly speaking, it was al-Fārābī who first drew the parallelism between deontic and modal concepts, it was Ibn Ḥazm who developed it and worked it out in a more precise manner. A primary aim of this paper is to help fill some of these gaps by stressing the role of the work of Ibn Ḥazm in developing a notion of deontic necessity deeply rooted in legal normativity, and in explicitly discussing the transference between deontic and modal concepts. According to our view; the basic units of Islamic deontic logic are what we might call, indulging in terminological anachronism, heteronomous imperatives. As it turns out, the heteronomy of imperatives within Islamic legal systems contrasts with those of the purely moral realm, which seem to be closer to an autonomous conception of moral law. There it concurs again with Leibniz’s proposal to define obligatory as “what is necessary for a good person to do”. In the present paper, we will focus on the heteronomous imperatives of legal systems rather than on the imperatives of the purely moral realm. In this context, the work of Ibn Ḥazm extends the parallelism between the necessity of events and that of human actions stressed by his predecessors. According to our understanding, Ibn Ḥazm’s parallelism can be rendered explicit formally by means of a conditional (or hypothetical) structure shared by both deontic and modal propositions. Moreover, this structure makes apparent that this parallelism displays an underlying system of “degrees”. Indeed, while in the domain of events, given some conditions, it makes sense to distinguish between an event that is more likely to happen than another. Ibn Ḥazm speaks of near and distant possibility (such as the higher degree of likelihood of rain, given the condensation of clouds in December, and its lower degree, when the condensation occurs in summer); and, in the domain of actions, the Islamic notion of weighting actions determines degrees of virtue (or of legal and moral value). So whereas the degree of virtue of performing a forbidden act as determined by the distribution of sanction and reward is 0, we obtain the same value by pondering the likelihood of an impossible event to take place. Furthermore, as discussed in section II.3.2, the system of values at work in the parallelism can be seen as opening the way to a more direct correspondence. Thus, while in the realm of nature, likelihood of occurrence of an event is dependent upon the conditions specific to the occurrence of that event; while, in the realm of jurisprudence, likelihood of performing an action is dependent upon the distribution of reward and sanction specific to that action (being that, given the choice to perform or not perform a given action, those that will be rewarded are more likely to be performed than those that are not). According to this perspective, the point of the parallelism is that both deontic and modal qualifications measure the degree of an action or event to become actual; that is – indulging once more in anachronism (but this time from the Leibnizian background) – the degree measures how feasible (facile) an action or event may be. This suggests that Ibn Ḥazm’s perspectives already herald the links to probability and possibility explored by Leibniz six centuries later – see for example Leibniz’s (1671, A VI, I, p. 424-26) use of probability in the context of conditional right. Nevertheless, it also shows a crucial difference to the approach developed in the Elementa Jura Naturalis: whereas Leibniz’s studies seek to define what is to be just or virtuous, the logical system of deontic imperatives within Islamic jurisprudence presupposes that what is to be virtuous has already been settled. Determining what is to be virtuous is not achieved by logical reasoning within the system of legal jurisprudence, but by delving into the higher objectives of the Sharīʿa. While developing our point, we will delve into the logical structure of the heteronomous imperatives. This distinguishes our contribution from the existing literature, such as the papers of Chejne (1984), Lameer (2014), and Guerrero (1997, 2010, 2014), which do not provide a logical analysis of the deontic concepts put into work by Ibn Ḥazm. The true antecedent to the present paper is the work of Farid Zidani (2007, 2015), who, so far as we know, was the first to undertake such a task. Some of our own developments and general epistemological thoughts go beyond Ibn Ḥazm’s framework and motivations; mainly those contained in sections II.3.2 and IV. However, according to our view, these reflections suggest that Ibn Ḥazm’s approach has the substance for a broader and deeper exploration of the logic of norms. The paper is structured as follows:I.Ibn Ḥazm’s Logic of Heteronomous Imperatives. After presenting some extracts of the relevant text, we proceed by providing a formal reconstruction of the five forms of deontic modalities. II. A Landmark in the History of the Logical Analysis of Norms. Duties and Modalities. In this section, we study the transferences from deontic to modal necessity and possibility. We briefly compare the deontic system of Islamic Jurisprudence with that of Leibniz.III. Leibniz and Hypothetical Imperatives in Law.IV. Beyond Ibn Ḥazm: Conclusions and the Work Ahead. We will conclude the paper by discussing briefly some conceptual points that distinguish the logic of heteronomous imperatives from contemporary deontic logic. Our final words will discuss deontic-modal parallelism in the context of Ibn Ḥazm’s rejection of reasoning by conjecture and what we call “the internalization of nature.”. (shrink)

Al-Taftāzānī introduces the Liar Paradox, in a commentary on al-Rāzī, in a short passage that is part of a polemic against the ethical rationalism of the Muʿtazila. In this essay, we consider his remarks and their place in the history of the Liar Paradox in Arabic Logic. In the passage, al-Taftāzānī introduces Liar Cycles into the tradition, gives the paradox a puzzling name—the fallacy of the “irrational root” —which became standard, and suggests a connection between the paradox and (...) what it tells us about truth and falsehood, and arguments for divine voluntarism and what they tell us about the nature of goodness and badness. On this last point, we also discuss a passage from al-Rāzī, which suggests similar connections. (shrink)

The philosophy is an important factor of education policy like the religion, heritage, culture and customs of the society .It concerns on the mind and its implication in our daily life. Philosophy focus on Logic, Science, Epistemology, Ethics and Esthetics which are important branches of human thoughts. During the human history, philosophy organizes education and the societies revert to philosophy to regulate education policy. In ancient time, Plato and Aristotle’s educational policy was established for Athens. For the Medieval, Al-Kindi, (...) Al-Farabi, Al-Razi, Ibn Sina, Ibn Tufail, and Ibn Rushd contributed to setting education policy in Arab culture. John Locke, Jean-Jacques Rousseau, Karl Marx and John Dewey elaborated philosophical theories of education. Philosophy contributes to: suggesting education goals, provide the learning outcome, classification of topics and learning activities in educational institutions , and proposes an educational curriculum. In this research, I will address these factors focusing on the fact that our present civilized societies need a philosophical dimension in organizing education policy. I will rely on philosophical theories, as well as contemporary studies that have been written on education policy in developed countries. (shrink)

Like lynching and other mass hysterias, xenophobia exemplifies a contagious, collective wave of energy and hedonic quality that can point toward a troubling unpredictability at the core of political and social systems. While earlier studies of mass hysteria and popular discourse assume that cooler heads (aka rational individuals with their logic) could and should regain control over those emotions that are deemed irrational, and that boundaries are assumed healthy only when intact, affect studies pose individuals as nodes of biosocial (...) networks larger than themselves. Thus rather than suggesting that the individual can only prevent societal harm by gaining command and patrolling the borders of an autonomous self, we embrace the notion that affects can exert a positive and transformative force on a social reality that is resistant to top-down policy intervention and any straightforward moral or logical plea. (shrink)

The text is a drought outlining the development of logic in Bosnia and Herzegovina through several periods of history: period of Ottoman occupation and administration of the Empire, period of Austro-Hungarian occupation and administration of the Monarchy, period of Communist regime and administration of the Socialist Republic and period from the aftermath of the aggression against the Republic of Bosnia and Herzegovina to this day (the Dayton Bosnia and Herzegovina) and administration of the International Community. For each of the (...) aforementioned periods, the text treats the organization of education, the educational paradigm of the model, status of logic as a subject in the educational system of a period, as well as the central figures dealing with the issue of logic (as researchers, lecturers, authors) and the key works written in each of the periods, outlining their main ideas. Thework of aNeoplatonic philosopher Porphyry, “Introduction” (Greek: Eisagogee), Latin: Isagoge; Arabic: Īsāġūğī), can be seen, in all periods of education in Bosnia and Herzegovina, as the main text, the principal textbook, as a motivation for logical thinking. That gave me the right to introduce the syntagm Bosnia Porphyriana. (shrink)

The article presents the chess composition as a logical art, with concrete examples. It began with Arabic mansuba, and later evolved to new-strategy designed by Italian Alberto Mari. The redefinition of mate (e.g. mate with a free field) or a theme to quasi-pseudo theme, opens the new space for combinations, and enables to connect it with other fields like computer science. The article was exhibited in Holland Park, W8 6LU, The Ice House between 18. Oct - 3. Nov. 2013.

In this fascinating book, Mehmet Karabela reveals the many roles assigned to Islam, Islamic history, the Ottoman Empire, Turks and Arabs by northern European Protestant intellectuals, mostly German Lutherans, from 1650 to 1800. The texts cover many topics that famously captivated European thinkers during a period which Karabela elects to call post-Reformation rather than Enlightenment. There are comparative studies of religion, philosophy, and literature. Karabela’s introduction provides a robust review of the historiography and offers context for patterns that emerge from (...) the texts. (shrink)

Early modern Protestant scholars closely engaged with Islamic thought in more ways than is usually recognized. Among Protestants, Lutheran scholars distinguished themselves as the most invested in the study of Islam and Muslim culture. Mehmet Karabela brings the neglected voices of post-Reformation theologians, primarily German Lutherans, into focus and reveals their rigorous engagement with Islamic thought. Inspired by a global history approach to religious thought, Islamic Thought Through Protestant Eyes offers new sources to broaden the conventional interpretation of the Reformation (...) beyond a solely European Christian phenomenon. -/- Based on previously unstudied dissertations, disputations, and academic works written in Latin in the seventeenth and eighteenth centuries, Karabela analyzes three themes: Islam as theology and religion; Islamic philosophy and liberal arts; and Muslim sects (Sunni and Shi‘a). This book provides analyses and translations of the Latin texts as well as brief biographies of the authors. -/- These texts offer insight into the Protestant perception of Islamic thought for scholars of religious studies and Islamic studies as well as for general readers. Examining the influence of Islamic thought on the construction of the Protestant identity after the Reformation helps us to understand the role of Islam in the evolution of Christianity. (shrink)

An essay on the philosophy of human nature in Islam, this article examines the views of contemporary Western thinkers to creatively rethink the concept of fiṭra, not only from a theological perspective but also a scientific perspective. Drawing upon Islamic scholarship and previous research on the subject that explore the wide spectrum of connotations couched in the Arabic term fiṭra in comparison with Western perspectives, this study offers a fresh look at, and approach to, the concept of human disposition (...) or primordial nature, giving special attention to the biological, epistemological, and ethical dimensions, while most studies of fiṭra focus mainly on the theological and spiritual sides. It is hoped that this conceptual analysis will serve as a stepping stone towards a more nuanced understanding of fiṭra not only as (i) a natural tendency to act or think in a particular way, but also as (ii) the religious instinct, (iii) the power of the mind to think and understand in a logical way, and (iv) the inner voice or conscience of what is right and wrong in one’s conduct or motives that drives the individual towards right action. (shrink)

Science and mathematics continually change in their tools, methods, and concepts. Many of these changes are not just modifications but progress---steps to be admired. But what constitutes progress? This dissertation addresses one central source of intellectual advancement in both disciplines: reformulating a problem-solving plan into a new, logically compatible one. For short, I call these cases of compatible problem-solving plans "reformulations." Two aspects of reformulations are puzzling. First, reformulating is often unnecessary. Given that we could already solve a problem using (...) an older formulation, what do we gain by reformulating? Second, some reformulations are genuinely trivial or insignificant. Merely replacing one symbol with another does not lead to intellectual progress. What distinguishes significant reformulations from trivial ones? According to what I call "conceptualism" (or "conceptual empiricism"), reformulations are intellectually significant when they provide a different plan for solving problems. Significant reformulations provide inferentially different routes to the same solution. In contrast, trivial reformulations provide exactly the same problem-solving plans, and hence they do not change our understanding. This answers the second question about what distinguishes trivial from significant reformulations. However, the first question remains: what makes a new way of solving an old problem valuable? Here, a bevy of practical considerations come to mind: one formulation might be faster, less complicated, or use more familiar concepts. According to "instrumentalism," these practical benefits are all there is to reformulating. Some reformulations are simply more instrumentally valuable for meeting the aims of science than others. At another extreme, "fundamentalism" contends that a reformulation is valuable when it provides a more fundamental description of reality. According to this view, some reformulations directly contribute to the metaphysical aim of carving reality at its joints. Conceptualism develops a middle ground between instrumentalism and fundamentalism, preserving their benefits without their costs. I argue that the epistemic value of significant reformulations does not reduce to either practical or metaphysical value. Reformulations are valuable because they are a constitutive part of problem-solving. Both science and mathematics aim at solving all possible problems within their respective domains. Meeting this aim requires being able to plan for any possible problem-solving context, and this requires reformulating. By reformulating, we clarify what we need to know to solve problems. Still, one might wonder whether the value of reformulations requires underlying differences in explanatory power. According to "explanationism," a reformulation is valuable only when it provides a better explanation. Explanationism stands as a rival middle ground position to my own. However, it faces numerous counterexamples. In many cases, two reformulations provide the same explanation while nonetheless providing different ways of understanding a phenomenon. Hence, reformulating can be valuable even when neither formulation is more explanatory. Methodologically, I draw on a variety of case studies to support my account of reformulation. These range from classical mechanics to quantum chemistry, along with examples from mathematics. Symmetry arguments provide a paradigmatic example: the mathematics of symmetry groups radically recasts quantum mechanics and quantum chemistry. Nevertheless, elementary approaches exist that eschew this additional mathematical apparatus, solving problems in a more tedious but less mathematically-demanding manner. Further examples include reformulations of quantum field theory, Arabic vs. Roman numerals, and Fermat's little theorem in number theory. In each case, my account identifies how reformulations change and improve our understanding of science and mathematics. (shrink)

The separation of Avicenna between Essence and Existence influenced logic and Arab and Muslim logicians in the Middle Ages among them Ibn al-Nafīs (1208-1288). Under this influence he contributed to the development of logic and especially the theory of the universal term. By means of the consequences of this analysis:-It has become possible to make a distinction between abstract concepts and formal concepts independent of any sensible reality, and hence the questioning of Aristotelian categories, that is to say (...) the ability to conceive for Ibn al-Nafīs like Avicenna, subjects and predicates which are not necessarily words expressing or belonging to one of the Aristotelian categories.-The analysis of the universal proposition as a conditional proposition, which made easier the distinction between absolute proposition which has no existential implication, and the other which differ from the first by an affirmation of explicit existence. (shrink)

“Neutrosophics Knowledge” has been created for publications on advanced studies in neutrosophy, neutrosophic set, neutrosophic logic, neutrosophic probability, neutrosophic statistics that started in 1995 and their applications in any field, such as the neutrosophic structures developed in algebra, geometry, topology, etc. The submitted papers should be professional, in good English and Arabic, containing a brief review of a problem and obtained results. Neutrosophy is a new branch of philosophy that studies the origin, nature, and scope of neutralities, as (...) well as their interactions with different ideational spectra. (shrink)

With regard to the new directions in the Humanities, here I am going to consider and examine the approach of al-Farabi as a medieval thinker in introducing a new outlook to “language” in difference with the other views. Thereby, I will explore his challenges in the frame of “philosophical humanism” as a term given by Arkoun (1970) and Kraemer (1984) to the humanism of the Islamic philosophers and their circles, mainly in the tenth and eleventh centuries. Al-Farabi’s conception of philosophical (...) humanism, in which philosophy is thick and religion is thin, makes its agony with the other versions of humanism and also orthodox Islam. It means that his introduction of a humanistic understanding of language should be placed in such a multi-level contested environment. According to al-Farabi, language as a universal category has relation with reason that logic should function as its proper instrument. As a result, there is no specific privileged predetermined language, but the position of any language is shaped by its relation with human reason and formal logic that is something human-made. And such a conception means language in human terms. Key Terms: Al-Farabi; Language; Philosophical Humanism; Arabic: Greek . (shrink)

This chapter explores the cultural varieties of same-sex relationships that have long been constituent of traditional African life. A recent study shows that roughly 10% of the global population identify as homosexuals. This number consistently and equitably cuts across all cultures of the world despite variations in attitude towards homosexuality. If this is true of the contemporary world, then it extends to the ancient and by that traditional Africa. Accordingly, this research using phenomenological and historico-descriptive tools of enquiry together with (...) ethnographical accounts of anthropologists retraces homosexuality to its African roots ranging from the practices of Hausas of West Africa, Zanzibars of East Africa, Ovagandjeras of Central Africa to those of the Herero, Ovambo, and Ovahimba peoples of Southern Africa. Consequently, this research avers that current attitude towards homosexuality in Africa is as a result of Western hegemony and the revolutionary changes effected by Euro-Christian and Arab-Islamic movements in their first and earlier contact with the continent. Hence, a fair disposition towards historical facts will deflate the current homophobic agitation, stripping it of any moral, historical or logical justification. (shrink)

Science was not far from philosophy in ancient thought, but the two were one thing. I do not know whether the ancient philosophers considered themselves the issue of the relationship between them, as the modern and contemporary philosophers did. But the sure thing is that the natural sciences became independent from philosophy in the modern era, and most of the scientific departments in universities were divided into two parts: sciences, literature, and humanities. At the end of the nineteenth century and (...) what followed, there were attempts to link them. Charles Peirce wrote on the scientific method and scientific metaphysics. The Vienna Circle presented a scientific conception of the world and the logical empiricists and Popper was concerned with the problem of distinguishing science from pseudoscience. The logical empiricists provided the criterion of verifiability, and Popper proposed the falsification principle. Quine defended a natural epistemology that asserts that philosophy is part of natural science. Bunge offered his own criteria for distinguishing science in the context of scientific philosophy. In this article, I want to refute the claim that philosophy has died and that science does not need it. I proved that the notion that philosophy is useless to science is not only wrong but also harmful to society, education, and science itself. This comes in a broader context, which is the moderate scientific tendency that I have defended in some of my writings. -/- لم يكن العلم بعيدًا عن الفلسفة في الفكر القديم، بل كان الاثنان شيئًا واحدًا. ولست أدرى أكان الفلاسفة القدماء يلقون على أنفسهم مسألة العلاقة بينهما مثل ما ألقاها الفلاسفة المحدثون والمعاصرون أم لا. ولكن الشيء المحقق أن العلوم الطبيعية استقلت عن الفلسفة في العصر الحديث، وانقسمت معظم الأقسام العلمية في الجامعات إلى قسمين: العلوم، والآداب والإنسانيات. وظهرت في أواخر القرن التاسع عشر وما تلاه محاولات لربطهما. كتب تشارلز بيرس عن المنهج العلمي والميتافيزيقا العلمية. وقدمت جماعة فيينا تصورًا علميًّا للعالم، واهتم التجريبيون المنطقيون وبوبر بمشكلة تمييز العلم من العلم الزائف؛ قدم التجريبيون المنطقيون معيار القابلية للتحقق، واقترح بوبر مبدأ التكذيب. ودافع كواين عن إبستمولوجيا طبيعية تؤكد أن الفلسفة جزء من العلم الطبيعي. وقدم بونجي معاييره الخاصة لتمييز العلم في سياق الفلسفة العلمية. (shrink)

Zeki Najib Mahmoud’s Critique of Greek Philosophy This research compares Dr. Zeki Najib Mahmoud’s criticism of Greek philosophy tenets to the original texts by focusing on five areas: 1.A criticism of the Platonic and Aristotelian concept of art. 2.A criticism of Plato’s metaphysics. 3. A criticism of Aristotle’s logic and his two theories relevant to identification and the four causes. 4.A criticism of the Greek philosophical concepts of the circle and virtue. 5.The employment of the analytical method in criticizing (...) Socrates and Aristotle. -/- The search endeavors to assess the strengths and weakness of Zeki Najib Mahmoud achievement through revealing the alternatives he propose regarding the issues he criticizes. (shrink)

Truth is a matter of interest not only to philosophers, but to scientists and other researchers in various branches of knowledge. This paper examines Davidson’s views of the concept of truth. In the first section, I provide a brief account of the basic ideas of Davidson’s philosophy. An understanding of Davidson’s philosophy is essential for anyone who wishes to follow recent debates in the philosophy of language, the philosophy of action, the philosophy of logic, and the philosophy of the (...) mind. I give also a brief sketch of the leading traditional theories of truth, i.e., coherence, correspondence and pragmatic theories. In the second section, I give a comprehensive account of Davidson’s main contributions to the truth - the conditions theory of meaning. That the meaning of a sentence can be given by stating the conditions under which it is true, is not a novel idea. It is at least as old as the work of Frege. In addition to Frege, this idea has been held by, among others, Wittgenstein, Carnap, Quine and - as its leader apologist and most recent proponent - Davidson. Before I look at the details of Davidson’s contributions, I show how they relate to the work of Frege, Tarski, and Quine, all of whom greatly influenced Davidson’s theory. Putnam, Dummett, Rorty and many other philosophers rank Davidson among the deflationists. They all think that Tarski’s truth predicates completely capture the concept of truth. This is a mistake. The third section is concerned with this mistake. In the fourth section, I explain Davidson’s criticisms of what he regards as the main other anti-deflationary attempts to characterize truth: views which epistemologize truth on the one hand, and the correspondence theory of truth, on the other hand. Finally, in the fifth section, I make some remarks about Davidson’s treatment of the concept of truth. (shrink)

Anti-exceptionalism about logic is the doctrine that logic does not require its own epistemology, for its methods are continuous with those of science. Although most recently urged by Williamson, the idea goes back at least to Lakatos, who wanted to adapt Popper's falsicationism and extend it not only to mathematics but to logic as well. But one needs to be careful here to distinguish the empirical from the a posteriori. Lakatos coined the term 'quasi-empirical' `for the counterinstances (...) to putative mathematical and logical theses. Mathematics and logic may both be a posteriori, but it does not follow that they are empirical. Indeed, as Williamson has demonstrated, what counts as empirical knowledge, and the role of experience in acquiring knowledge, are both unclear. Moreover, knowledge, even of necessary truths, is fallible. Nonetheless, logical consequence holds in virtue of the meaning of the logical terms, just as consequence in general holds in virtue of the meanings of the concepts involved; and so logic is both analytic and necessary. In this respect, it is exceptional. But its methodologyand its epistemology are the same as those of mathematics and science in being fallibilist, and counterexamples to seemingly analytic truths are as likely as those in any scientic endeavour. What is needed is a new account of the evidential basis of knowledge, one which is, perhaps surprisingly, found in Aristotle. (shrink)

If modus ponens is valid, then you should take up smoking.

This paper establishes a sound and complete semantics for the impure logic of ground. Fine (Review of Symbolic Logic, 5(1), 1–25, 2012a) sets out a system for the pure logic of ground, one in which the formulas between which ground-theoretic claims hold have no internal logical complexity; and it provides a sound and complete semantics for the system. Fine (2012b) [§§6-8] sets out a system for an impure logic of ground, one that extends the rules of (...) the original pure system with rules for the truth-functional connectives, the first-order quantifiers, and λ-abstraction. However, no semantics has yet been provided for this system. The present paper partly fills this lacuna by providing a sound and complete semantics for a system GG containing the truth-functional operators that is closely related to the truth-functional part of the system of Fine (2012b). (shrink)

At least since Aristotle’s famous 'sea-battle' passages in On Interpretation 9, some substantial minority of philosophers has been attracted to the doctrine of the open future--the doctrine that future contingent statements are not true. But, prima facie, such views seem inconsistent with the following intuition: if something has happened, then (looking back) it was the case that it would happen. How can it be that, looking forwards, it isn’t true that there will be a sea battle, while also being true (...) that, looking backwards, it was the case that there would be a sea battle? This tension forms, in large part, what might be called the problem of future contingents. A dominant trend in temporal logic and semantic theorizing about future contingents seeks to validate both intuitions. Theorists in this tradition--including some interpretations of Aristotle, but paradigmatically, Thomason (1970), as well as more recent developments in Belnap, et. al (2001) and MacFarlane (2003, 2014)--have argued that the apparent tension between the intuitions is in fact merely apparent. In short, such theorists seek to maintain both of the following two theses: (i) the open future: Future contingents are not true, and (ii) retro-closure: From the fact that something is true, it follows that it was the case that it would be true. It is well-known that reflection on the problem of future contingents has in many ways been inspired by importantly parallel issues regarding divine foreknowledge and indeterminism. In this paper, we take up this perspective, and ask what accepting both the open future and retro-closure predicts about omniscience. When we theorize about a perfect knower, we are theorizing about what an ideal agent ought to believe. Our contention is that there isn’t an acceptable view of ideally rational belief given the assumptions of the open future and retro-closure, and thus this casts doubt on the conjunction of those assumptions. (shrink)

A key question in the philosophy of logic is how we have epistemic justification for claims about logical entailment (assuming we have such justification at all). Justification holism asserts that claims of logical entailment can only be justified in the context of an entire logical theory, e.g., classical, intuitionistic, paraconsistent, paracomplete etc. According to holism, claims of logical entailment cannot be atomistically justified as isolated statements, independently of theory choice. At present there is a developing interest in—and endorsement of—justification (...) holism due to the revival of an abductivist approach to the epistemology of logic. This paper presents an argument against holism by establishing a foundational entailment-sentence of deduction which is justified independently of theory choice and outside the context of a whole logical theory. (shrink)

In this paper we re-assess the philosophical foundation of Exactly True Logic ($$\mathcal {ET\!L}$$ ET L ), a competing variant of First Degree Entailment ($$\mathcal {FDE}$$ FDE ). In order to do this, we first rebut an argument against it. As the argument appears in an interview with Nuel Belnap himself, one of the fathers of $$\mathcal {FDE}$$ FDE, we believe its provenance to be such that it needs to be taken seriously. We submit, however, that the argument ultimately (...) fails, and that $$\mathcal {ET\!L}$$ ET L cannot easily be dismissed. We then proceed to give an overview of the research that was inspired by this logic over the last decade, thus providing further motivation for the study of $$\mathcal {ET\!L}$$ ET L and, more generally, of $$\mathcal {FDE}$$ FDE -related logics that result from semantical analyses alternative to Belnap’s canonical one. We focus, in particular, on philosophical questions that these developments raise. (shrink)

This paper studies a formalisation of intuitionistic logic by Negri and von Plato which has general introduction and elimination rules. The philosophical importance of the system is expounded. Definitions of ‘maximal formula’, ‘segment’ and ‘maximal segment’ suitable to the system are formulated and corresponding reduction procedures for maximal formulas and permutative reduction procedures for maximal segments given. Alternatives to the main method used are also considered. It is shown that deductions in the system convert into normal form and that (...) deductions in normal form have the subformula property. (shrink)

I propose that an irreducible property of physical space — consistency — is the origin of logic. I propose that an inconsistent space is inconceivable and that this inconceivability can be recognized as the force behind logical propositions. The implications of this argument are briefly explored and then applied to address two paradoxes: Zeno of Elea’s paradox regarding the race between Achilles and the Tortoise, and Lewis Carroll’s paradox regarding the Tortoise’s conversation with Achilles after the race. I conclude (...) that Achilles would have won on both accounts, in the race and the argument, by invoking the consistency of space as the foundation of both movement across space and logical argument. (shrink)

This paper deals with the study of the nature of mind, its processes and its relations with the other filed known as logic, especially the contribution of most notable contemporary analytical philosophy Ludwig Wittgenstein. Wittgenstein showed a critical relation between the mind and logic. He assumed that every mental process is logical. Mental field is field of space and time and logical field is a field of reasoning (inductive and deductive). It is only with the advancement in (...) class='Hi'>logic, we are today in the era of scientific progress and technology. Logic played an important role in the cognitive part or we can say in the ‗philosophy of mind‘ that this branch is developed only because of three crucial theories i.e. rationalism, empiricism, and criticism. In this paper, it is argued that innate ideas or truth are equated with deduction and acquired truths are related with induction. This article also enhance the role of language in the makeup of the world of mind, although mind and the thought are the terms that are used by the philosophers synonymously but in this paper they are taken and interpreted differently. It shows the development in the analytical tradition subjected to the areas of mind and logic and their critical relation. (shrink)

This paper shows how to conservatively extend classical logic with a transparent truth predicate, in the face of the paradoxes that arise as a consequence. All classical inferences are preserved, and indeed extended to the full (truth—involving) vocabulary. However, not all classical metainferences are preserved; in particular, the resulting logical system is nontransitive. Some limits on this nontransitivity are adumbrated, and two proof systems are presented and shown to be sound and complete. (One proof system allows for Cut—elimination, but (...) the other does not.). (shrink)

Gila Sher interviewed by Chen Bo: -/- I. Academic Background and Earlier Research: 1. Sher’s early years. 2. Intellectual influence: Kant, Quine, and Tarski. 3. Origin and main Ideas of The Bounds of Logic. 4. Branching quantifiers and IF logic. 5. Preparation for the next step. -/- II. Foundational Holism and a Post-Quinean Model of Knowledge: 1. General characterization of foundational holism. 2. Circularity, infinite regress, and philosophical arguments. 3. Comparing foundational holism and foundherentism. 4. A post-Quinean model (...) of knowledge. 5. Intellect and figuring out. 6. Comparing foundational holism with Quine’s holism. 7. Evaluation of Quine’s Philosophy -/- III. Substantive Theory of Truth and Relevant Issues: 1. Outline of Sher’s substantive theory of truth. 2. Criticism of deflationism and treatment of the Liar. 3. Comparing Sher’s substantive theory of truth with Tarski’s theory of truth. -/- IV. A New Philosophy of Logic and Comparison with Other Theories: 1. Foundational account of logic. 2. Standard of logicality, set theory and logic. 3. Psychologism, Hanna’s and Maddy’s conceptions of logic. 4. Quine’s theses about the revisability of logic. -/- V. Epilogue. (shrink)

This paper presents a new system of logic, LF, that is intended to be used as the foundation of the formalization of science. That is, deductive validity according to LF is to be used as the criterion for assessing what follows from the verdicts, hypotheses, or conjectures of any science. In work currently in progress, we argue for the unique suitability of LF for the formalization of logic, mathematics, syntax, and semantics. The present document specifies the language and (...) rules of LF, lays out some notational conventions, and states some basic technical facts about the system. (shrink)

The purpose of this paper is to introduce a bi-intuitionistic sequent calculus and to give proofs of admissibility for its structural rules. The calculus I will present, called SC2Int, is a sequent calculus for the bi-intuitionistic logic 2Int, which Wansing presents in [2016a]. There he also gives a natural deduction system for this logic, N2Int, to which SC2Int is equivalent in terms of what is derivable. What is important is that these calculi represent a kind of bilateralist reasoning, (...) since they do not only internalize processes of verifcation or provability but also the dual processes in terms of falsifcation or what is called dual provability. In [Wansing, 2017] a normal form theorem for N2Int is stated, here, I want to prove a cut-elimination theorem for SC2Int, i.e., if successful, this would extend the results existing so far. (shrink)

This paper presents rules of inference for a binary quantifier I for the formalisation of sentences containing definite descriptions within intuitionist positive free logic. I binds one variable and forms a formula from two formulas. Ix[F, G] means ‘The F is G’. The system is shown to have desirable proof-theoretic properties: it is proved that deductions in it can be brought into normal form. The discussion is rounded up by comparisons between the approach to the formalisation of definite descriptions (...) recommended here and the more usual approach that uses a term-forming operator ι, where ιxF means ‘the F’. (shrink)

forall x: Calgary is a full-featured textbook on formal logic. It covers key notions of logic such as consequence and validity of arguments, the syntax of truth-functional propositional logic TFL and truth-table semantics, the syntax of first-order (predicate) logic FOL with identity (first-order interpretations), symbolizing English in TFL and FOL, and Fitch-style natural deduction proof systems for both TFL and FOL. It also deals with some advanced topics such as modal logic, soundness, and functional completeness. (...) Exercises with solutions are available. It is provided in PDF (for screen reading, printing, and a special version for dyslexics), HTML, and in LaTeX source code. (shrink)

In this paper we distinguish between various kinds of doxastic theories. One distinction is between informal and formal doxastic theories. AGM-type theories of belief change are of the former kind, while Hintikka’s logic of knowledge and belief is of the latter. Then we distinguish between static theories that study the unchanging beliefs of a certain agent and dynamic theories that investigate not only the constraints that can reasonably be imposed on the doxastic states of a rational agent but also (...) rationality constraints on the changes of doxastic state that may occur in such agents. An additional distinction is that between non-introspective theories and introspective ones. Non-introspective theories investigate agents that have opinions about the external world but no higher-order opinions about their own doxasticnstates. Standard AGM-type theories as well as the currently existing versions of Segerberg’s dynamic doxastic logic (DDL) are non-introspective. Hintikka-style doxastic logic is of course introspective but it is a static theory. Thus, the challenge remains to devise doxastic theories that are both dynamic and introspective. We outline the semantics for truly introspective dynamic doxastic logic, i.e., a dynamic doxastic logic that allows us to describe agents who have both the ability to form higher-order beliefs and to reflect upon and change their minds about their own (higher-order) beliefs. This extension of DDL demands that we give up the Preservation condition on revision. We make some suggestions as to how such a non-preservative revision operation can be constructed. We also consider extending DDL with conditionals satisfying the Ramsey test and show that Gärdenfors’ well-known impossibility result applies to such a framework. Also in this case, Preservation has to be given up. (shrink)

In this paper I discuss a prevailing view by which logical terms determine forms of sentences and arguments and therefore the logical validity of arguments. This view is common to those who hold that there is a principled distinction between logical and nonlogical terms and those holding relativistic accounts. I adopt the Tarskian tradition by which logical validity is determined by form, but reject the centrality of logical terms. I propose an alternative framework for logic where logical terms no (...) longer play a distinctive role. This account employs a new notion of semantic. (shrink)

(1) This paper is about how to build an account of the normativity of logic around the claim that logic is constitutive of thinking. I take the claim that logic is constitutive of thinking to mean that representational activity must tend to conform to logic to count as thinking. (2) I develop a natural line of thought about how to develop the constitutive position into an account of logical normativity by drawing on constitutivism in metaethics. (3) (...) I argue that, while this line of thought provides some insights, it is importantly incomplete, as it is unable to explain why we should think. I consider two attempts at rescuing the line of thought. The first, unsuccessful response is that it is self-defeating to ask why we ought to think. The second response is that we need to think. But this response secures normativity only if thinking has some connection to human flourishing. (4) I argue that thinking is necessary for human flourishing. Logic is normative because it is constitutive of this good. (5) I show that the resulting account deals nicely with problems that vex other accounts of logical normativity. (shrink)

Although arguments for and against competing theories of vagueness often appeal to claims about the use of vague predicates by ordinary speakers, such claims are rarely tested. An exception is Bonini et al. (1999), who report empirical results on the use of vague predicates by Italian speakers, and take the results to count in favor of epistemicism. Yet several methodological difficulties mar their experiments; we outline these problems and devise revised experiments that do not show the same results. We then (...) describe three additional empirical studies that investigate further claims in the literature on vagueness: the hypothesis that speakers confuse ‘P’ with ‘definitely P’, the relative persuasiveness of different formulations of the inductive premise of the Sorites, and the interaction of vague predicates with three different forms of negation. (shrink)

This paper presents a recent formalization of a Henkin-style completeness proof for the propositional modal logic S5 using the Lean theorem prover. The proof formalized is close to that of Hughes and Cresswell, but the system, based on a different choice of axioms, is better described as a Mendelson system augmented with axiom schemes for K, T, S4, and B, and the necessitation rule as a rule of inference. The language has the false and implication as the only primitive (...) logical connectives and necessity as the only primitive modal operator. The full source code is available online and has been typechecked with Lean 3.4.2. (shrink)

This essay is part of larger project in which I attempt to show that Western formal logic, from its inception in Aristotle onward, has both been partially constituted by, and partially constitutive of, what has become known as racism. More specifically, (a) racist/quasi-racist/proto-racist political forces were part of the impetus for logic’s attempt to classify the world into mutually exclusive, hierarchically-valued categories in the first place; and (b) these classifications, in turn, have been deployed throughout history to justify (...) and empower racism/quasi-racism/proto-racism. In other words, (a) an important part of the chaos and messiness that so troubles logic has been the natural bio-cultural diversity of human beings as described by concepts such as race and ethnicity; and (b) once these concepts were historically in place, taken for granted, buttressed with pseudo-science, and had their origins forgotten, they became tools for the oppression of diverse human groups. The central thesis of this essay is that close readings of a variety of Leibniz’s writings (including several essays and one letter) will reveal a pattern of mutual dependency and creation in regard to logic and racism in Leibniz. My conclusion will be that there is a meaningful connection between logic and racism (or at least between logic and politics in general) in Leibniz such that one should be skeptical of his logic’s claim to offer transparent and neutral descriptions of the world as well as imperatives for action. Put differently, I want to ask the following specific question: how do Leibniz’s own racially-informed political goals, along with the emergence of race-centric European colonialism, both invest and disguise themselves within Leibniz’s mathematizing of logic? (shrink)

Supervaluationism is often described as the most popular semantic treatment of indeterminacy. There’s little consensus, however, about how to fill out the bare-bones idea to include a characterization of logical consequence. The paper explores one methodology for choosing between the logics: pick a logic thatnorms beliefas classical consequence is standardly thought to do. The main focus of the paper considers a variant of standard supervaluational, on which we can characterizedegrees of determinacy. It applies the methodology above to focus ondegree (...) logic. This is developed first in a basic, single-premise case; and then extended to the multipremise case, and to allowdegreesof consequence. The metatheoretic properties of degree logic are set out. On the positive side, the logic is supraclassical—all classical valid sequents are degree logic valid. Strikingly, metarules such as cut and conjunction introduction fail. (shrink)

The idea that logic is in some sense normative for thought and reasoning is a familiar one. Some of the most prominent figures in the history of philosophy including Kant and Frege have been among its defenders. The most natural way of spelling out this idea is to formulate wide-scope deductive requirements on belief which rule out certain states as irrational. But what can account for the truth of such deductive requirements of rationality? By far, the most prominent responses (...) draw in one way or another on the idea that belief aims at the truth. In this paper, I consider two ways of making this line of thought more precise and I argue that they both fail. In particular, I examine a recent attempt by Epistemic Utility Theory to give a veritist account of deductive coherence requirements. I argue that despite its proponents’ best efforts, Epistemic Utility Theory cannot vindicate such requirements. (shrink)

In this paper I investigate how differences in approach to truth and logic (in particular, a deflationist vs. a substantivist approach to these fields) affect philosophers’ views concerning pluralism and normativity in these fields. My perspective on truth and logic is largely epistemic, focusing on the role of truth in knowledge (rather than on the use of the words “true” and “truth” in natural language), and my reference group includes Carnap (1934), Harman (1986), Horwich (1990), Wright (1992), Beall (...) and Restall (2006), Field (2009), Lynch (2009), and Sher (2016a).1 Whenever possible, I focus on positive rather than negative views on the issues involved, although in some cases this is not possible. (shrink)

Developing a suggestion of Wittgenstein, I provide an account of truth tables as formulas of a formal language. I define the syntax and semantics of TPL (the language of Tabular Propositional Logic), and develop its proof theory. Single formulas of TPL, and finite groups of formulas with the same top row and TF matrix (depiction of possible valuations), are able to serve as their own proofs with respect to metalogical properties of interest. The situation is different, however, for groups (...) of formulas whose top rows differ. For them I provide (i) a tree-style system of ‘row tree proofs’, which is shown to be sound and complete, and (ii) an alternative, re-writing strategy. (shrink)

In this paper, we present a survey of the development of the technique of argument diagramming covering not only the fields in which it originated - informal logic, argumentation theory, evidence law and legal reasoning – but also more recent work in applying and developing it in computer science and artificial intelligence. Beginning with a simple example of an everyday argument, we present an analysis of it visualised as an argument diagram constructed using a software tool. In the context (...) of a brief history of the development of diagramming, it is then shown how argument diagrams have been used to analyze and work with argumentation in law, philosophy and artificial intelligence. (shrink)

There are many domains about which we think we are reliable. When there is prima facie reason to believe that there is no satisfying explanation of our reliability about a domain given our background views about the world, this generates a challenge to our reliability about the domain or to our background views. This is what is often called the reliability challenge for the domain. In previous work, I discussed the reliability challenges for logic and for deductive inference. I (...) argued for four main claims: First, there are reliability challenges for logic and for deduction. Second, these reliability challenges cannot be answered merely by providing an explanation of how it is that we have the logical beliefs and employ the deductive rules that we do. Third, we can explain our reliability about logic by appealing to our reliability about deduction. Fourth, there is a good prospect for providing an evolutionary explanation of the reliability of our deductive reasoning. In recent years, a number of arguments have appeared in the literature that can be applied against one or more of these four theses. In this paper, I respond to some of these arguments. In particular, I discuss arguments by Paul Horwich, Jack Woods, Dan Baras, Justin Clarke-Doane, and Hartry Field. (shrink)