Translation of Aristotle's Physics I-II into Portuguese, with commentaries. Tradução para o português dos livros I e II da Física de Aristóteles, com comentários.

We present epistemic multilateral logic, a general logical framework for reasoning involving epistemic modality. Standard bilateral systems use propositional formulae marked with signs for assertion and rejection. Epistemic multilateral logic extends standard bilateral systems with a sign for the speech act of weak assertion (Incurvati and Schlöder 2019) and an operator for epistemic modality. We prove that epistemic multilateral logic is sound and complete with respect to the modal logic S5 modulo an appropriate translation. The logical framework developed provides the (...) basis for a novel, proof-theoretic approach to the study of epistemic modality. To demonstrate the fruitfulness of the approach, we show how the framework allows us to reconcile classical logic with the contradictoriness of so-called Yalcin sentences and to distinguish between various inference patterns on the basis of the epistemic properties they preserve. (shrink)

We discuss a well-known puzzle about the lexicalization of logical operators in natural language, in particular connectives and quantifiers. Of the many logically possible operators, only few appear in the lexicon of natural languages: the connectives in English, for example, are conjunction _and_, disjunction _or_, and negated disjunction _nor_; the lexical quantifiers are _all, some_ and _no_. The logically possible nand (negated conjunction) and Nall (negated universal) are not expressed by lexical entries in English, nor in any natural language. Moreover, (...) the lexicalized operators are all upward or downward monotone, an observation known as the Monotonicity Universal. We propose a logical explanation of lexical gaps and of the Monotonicity Universal, based on the dynamic behaviour of connectives and quantifiers. We define update potentials for logical operators as procedures to modify the context, under the assumption that an update by \( \phi \) depends on the logical form of \( \phi \) and on the speech act performed: assertion or rejection. We conjecture that the adequacy of update potentials determines the limits of lexicalizability for logical operators in natural language. Finally, we show that on this framework the Monotonicity Universal follows from the logical properties of the updates that correspond to each operator. (shrink)

Tradução preliminar em pré-print. A Tradução definitiva é a de 2009.

We present an inferentialist account of the epistemic modal operator might. Our starting point is the bilateralist programme. A bilateralist explains the operator not in terms of the speech act of rejection ; we explain the operator might in terms of weak assertion, a speech act whose existence we argue for on the basis of linguistic evidence. We show that our account of might provides a solution to certain well-known puzzles about the semantics of modal vocabulary whilst retaining classical logic. (...) This demonstrates that an inferentialist approach to meaning can be successfully extended beyond the core logical constants. (shrink)

ABSTRACTLinguistic evidence supports the claim that certain, weak rejections are less specific than assertions. On the basis of this evidence, it has been argued that rejected sentences cannot be premisses and conclusions in inferences. We give examples of inferences with weakly rejected sentences as premisses and conclusions. We then propose a logic of weak rejection which accounts for the relevant phenomena and is motivated by principles of coherence in dialogue. We give a semantics for which this logic is sound and (...) complete, show that it axiomatizes the modal logic KD45 and prove that it still derives classical logic on its asserted fragment. Finally, we defend previous logics of strong rejection as being about the linguistically preferred interpretations of weak rejections. (shrink)

This is an introductory handbook for some of the main themes around the notion of predication in Aristotle. It does not aim at being exhaustive, but only sketches some important lines about the subject; it contains an introductory essay, besides the translation (into Portuguese) and commentary of basic texts (such as Posterior Analytics I-22, Categories 1-5, Interpretation 1-6 etc.).

These are commentaries to the translation into Portuguese of Nicomachean Ethics VI, found in the same volume of Dissertatio.

Translation of Aristotle's Posterior Analytics I into Portuguese, with a few notes, experimental glossary and introduction. The translation, which was made at 2003/4, was preliminary and its publication was intended to provide a didactic tool for courses as well as a provisional resource in research seminars. It needs some revision. I am currently working (slowly...) on the revision of the translation and a new revised one will surely appear at some point.

Translation of Aristotle's Metaphysics IV and VI, with notes. The translation is preliminary and intended as a provisional teaching tool to be also used in seminars and discussions with peers in order to reach a more elaborated version.

Tradução para o Português de Ethica Nicomachea VI.

Paul Feyerabend, one of the most original and nonconformist epistemologists of the 20th century, is known for describing science as an essentially anarchic enterprise characterized by different, sometimes contradictory, methods, approaches and ways of reasoning. But it was through his reflections on art and myth that he developed an even more radical view: there are different forms of human thought, each characterized by a different rationality and reality, and science is only one of them. And in intellectual history there is (...) only change, but not progress. (shrink)

This book discusses Aristotle’s notions of essence and substance as they are developed in Metaphysics ZH. I examine Aristotle's argument at length and defends an unorthodox interpretation according to which his motivation is to provide an answer against a conflation between criteria for existential priority (delivering substances as primary beings) and criteria for explanatory priority (delivering essences as primary principles).

The question as to whether Ian Hacking’s project of scientific styles of thinking entails epistemic relativism has received considerable attention. However, scholars have never discussed it vis-à-vis Wittgenstein. This is unfortunate: not only is Wittgenstein the philosopher who, together with Foucault, has influenced Hacking the most, but he has also faced the same accusation of ‘relativism’. I shall explore the conceptual similarities and differences between Hacking’s notion of style of thinking and Wittgenstein’s conception of form of life. It is a (...) fact that whether or not the latter entails epistemic relativism is still a controversial question. From my comparative analysis, it will emerge that there are stronger reasons to conclude that Hacking’s notion of style leads to epistemic relativism than there are to reach the same conclusion in the case of Wittgenstein’s conception of form of life. This point will be at odds with the anti-relativistic stance that Hacking has taken in his more recent writings. (shrink)

Collective volume with papers by alumni and students from the Campinas Aristotle Group.

We develop a novel solution to the negation version of the Frege-Geach problem by taking up recent insights from the bilateral programme in logic. Bilateralists derive the meaning of negation from a primitive *B-type* inconsistency involving the attitudes of assent and dissent. Some may demand an explanation of this inconsistency in simpler terms, but we argue that bilateralism’s assumptions are no less explanatory than those of *A-type* semantics that only require a single primitive attitude, but must stipulate inconsistency elsewhere. Based (...) on these insights, we develop a version of B-type expressivism called *inferential expressivism*. This is a novel semantic framework that characterises meanings by inferential roles that define which *attitudes* one can *infer* from the use of terms. We apply this framework to normative vocabulary, thereby solving the Frege-Geach problem generally and comprehensively. Our account moreover includes a semantics for epistemic modals, thereby also explaining normative terms under epistemic modals. (shrink)

In Posterior Analytics 71b9 12, we find Aristotle’s definition of scientific knowledge. The definiens is taken to have only two informative parts: scientific knowledge must be knowledge of the cause and its object must be necessary. However, there is also a contrast between the definiendum and a sophistic way of knowing, which is marked by the expression “kata sumbebekos”. Not much attention has been paid to this contrast. In this paper, I discuss Aristotle’s definition paying due attention to this contrast (...) and to the way it interacts with the two conditions presented in the definiens. I claim that the “necessity” condition ammounts to explanatory appropriateness of the cause. (shrink)

I discuss the argument Aristotle ascribes to Parmenides at Physics 186a23-32. I discuss (i) the reasons why Aristotle considers it as eristic and inconclusive and (i) the solution (lusis) Aristotle proposes against it.

Translation of Aristotle's Metaphysics I-III into Portuguese, with a few notes and introduction. The translation, which was made at 2007, is preliminary and its publication was intended to provide a didactic tool for courses as well as a provisional resource in research seminars. It needs some revision. I am currently working (slowly...) on the revision of the translation and a new revised one will surely appear at some point.

Translation of Aristotle's Parts of Animals Book I into Portuguese, with full commentaries.

This chapter argues in favour of three interrelated points. First, I argue that demonstration (as expression of scientific knowledge) is fundamentally defined as knowledge of the appropriate cause for a given explanandum: to have scientific knowledge of the explanandum is to explain it through its fully appropriate cause. Secondly, I stress that Aristotle’s notion of cause has a “triadic” structure, which fundamentally depends on the predicative formulation (or “regimentation”) of the explanandum. Thirdly, I argue that what has motivated Aristotle to (...) choose the syllogism as a demonstrative tool was precisely the fact that syllogisms are apt to express causal relations in their triadic structure. Instead of complaining against Aristotle’s preference for the syllogisms as demonstrative tools, I argue that Aristotle was fully aware of the advantages of regimenting the explanandum into a predication. One of these advantages is to abandon a purely extensional standpoint and to highlight the importance of the notion of relevancy in explanation. (shrink)

Experiences like pains, pleasures, and emotions have affective phenomenal character: they feel pleasant or unpleasant. Imperativism proposes to explain affective phenomenal character by appeal to imperative content, a kind of intentional content that directs rather than describes. We argue that imperativism is on the right track, but has been developed in the wrong way. There are two varieties of imperativism on the market: first-order and higher-order. We show that neither is successful, and offer in their place a new theory: reflexive (...) imperativism. Our proposal is that an experience P feels pleasant in virtue of being constituted by a Command with reflexive imperative content, while an experience U feels unpleasant in virtue of being constituted by a Command with reflexive imperative content : More of P!Less of U! If you need a slogan: experiences have affective phenomenal character in virtue of commanding us Get more of me! Get less of me! (shrink)

Deflationists about truth hold that the function of the truth predicate is to enable us to make certain assertions we could not otherwise make. Pragmatists claim that the utility of negation lies in its role in registering incompatibility. The pragmatist insight about negation has been successfully incorporated into bilateral theories of content, which take the meaning of negation to be inferentially explained in terms of the speech act of rejection. We implement the deflationist insight in a bilateral theory by taking (...) the meaning of the truth predicate to be explained by its inferential relation to assertion. We combine this account of the meaning of the truth predicate with a new diagnosis of the Liar Paradox: its derivation requires the truth rules to preserve evidence, but these rules only preserve commitment. The result is a novel inferential deflationist theory of truth, which solves the Liar Paradox in a principled manner. We end by showing that our theory and simple extensions thereof have the resources to axiomatize the internal logic of several supervaluational hierarchies, including Cantini’s. This solves open problems of Halbach (2011) and Horsten (2011). (shrink)

I discuss an important feature of the notion of cause in Post. An. 1. 13, 78b13–28, which has been either neglected or misunderstood. Some have treated it as if Aristotle were introducing a false principle about explanation; others have understood the point in terms of coextensiveness of cause and effect. However, none offers a full exegesis of Aristotle's tangled argument or accounts for all of the text's peculiarities. My aim is to disentangle Aristotle's steps to show that he is arguing (...) in favour of a logical requirement for a middle term's being the appropriate cause of its explanandum. Coextensiveness between the middle term and the attribute it explains is advanced as a sine qua non condition of a middle term's being an appropriate or primary cause. This condition is not restricted either to negative causes or to middle terms in second‐figure syllogisms, but ranges over all primary causes qua primary. (shrink)

Many classically valid meta-inferences fail in a standard supervaluationist framework. This allegedly prevents supervaluationism from offering an account of good deductive reasoning. We provide a proof system for supervaluationist logic which includes supervaluationistically acceptable versions of the classical meta-inferences. The proof system emerges naturally by thinking of truth as licensing assertion, falsity as licensing negative assertion and lack of truth-value as licensing rejection and weak assertion. Moreover, the proof system respects well-known criteria for the admissibility of inference rules. Thus, supervaluationists (...) can provide an account of good deductive reasoning. Our proof system moreover brings to light how one can revise the standard supervaluationist framework to make room for higher-order vagueness. We prove that the resulting logic is sound and complete with respect to the consequence relation that preserves truth in a model of the non-normal modal logic _NT_. Finally, we extend our approach to a first-order setting and show that supervaluationism can treat vagueness in the same way at every order. The failure of conditional proof and other meta-inferences is a crucial ingredient in this treatment and hence should be embraced, not lamented. (shrink)

Translation of Aristotle’s Metaphysics IX and X (Theta & Iota) into Portuguese, with a few notes, experimental glossary and introduction. The translation, which was made at 2004, is preliminary and its publication was intended to provide a didactic tool for courses as well as a provisional resource in research seminars. It needs some revision. I am currently working (slowly...) on the revision of the translation and a new revised one will surely appear at some point.

Aristotle contrasts episteme and doxa through the key notions of universal and necessary. These notions have played a central role in Aristotle’s characterization of scientific knowledge in the previous chapters of APo. They are not spelled out in APo I.33, but work as a sort of reminder that packs an adequate characterization of scientific knowledge and thereby gives a highly specified context for Aristotle’s contrast between episteme and doxa. I will try to show that this context introduces a contrast in (...) terms of explanatory claims: on the one hand, episteme covers those claims which capture explanatory connections that are universal and necessary and thereby deliver scientific understanding; on the other hand, doxa covers the explanatory attempts that fail at doing so. (shrink)

I discuss the exact meaning of the thesis according to which the object of scientific knowledge is necessary. The thesis is expressed by Aristotle in the Posterior Analytics, in his definition of scientific knowledge. The traditional interpretation understands this definition as depending on two parallel and independent requirements, the causality requirement and the necessity requirement. Against this interpretation, I try to show, through the examination of several passages that refer to the definition of scientific knowledge, that the necessity requirement specifies (...) more exactly the causality requirement: what cannot be otherwise is the explanatory relation between the explanandum and the cause by which it is what it is. (shrink)

Este livro é um 'ancestral' em pré-print do meu livro de 2006, Introdução à Teoria da Predicação em Aristóteles (ISBN 978-85-268-0716-1), publicado pela Editora da Unicamp (ver https://www.academia.edu/6912408/Introdu%C3%A7%C3%A3o_%C3%A0_teoria_da_predica%C3%A7%C3%A3o_em_Arist %C3%B3teles). O ancestral foi felizmente muito citado, mesmo depois da aparição do livro definitivo em 2006. -/- This is an ancestor (in pré-print) of my 2006 Book, 'Introdução à Teoria da Predicação em Aristóteles' (ISBN 978-85-268-0716-1), published by Editora da Unicamp (see https://www.academia.edu/6912408/Introdu%C3%A7%C3%A3o_%C3%A0_teoria_da_predica%C3%A7%C3%A3o_em_Arist %C3%B3teles). The ancestor was cited by many, even after the definitive book (...) appeared in 2006. (shrink)

In this paper, I argue against the popular philosophical thesis---aka the ‘own action condition’---that an agent can only intend one’s own actions. I argue that the own action condition does not hold for any executive attitude, intentions included. The proper object of intentions is propositional rather than agential (‘I intend that so-and-so be the case’ rather than ‘I intend to do such-and-such’). I show that, although there are some essential de se components in intending, they do not restrict the content (...) of intentions to one’s own actions. I then discuss the special way in which one’s own actions can figure in the content of one’s intentions, which shows that the distinction between intending and acting is less stark than it appears at first. This is a conclusion that many defenders of the own action condition might find appealing but which, I argue, is better supported by rejecting the own action condition. (shrink)

I discuss in this paper the six requirements Aristotle advances at Posterior Analytics A-2, 71b20-33, for the premisses of a scientific demonstration. I argue that the six requirements give no support for an intepretation in terms of “axiomatization”. Quite on the contrary, the six requirements can be consistently understood in a very different picture, according to which the most basic feature of a scientific demonstration is to explain a given proposition by its appropriate cause.

Translation of Aristotle's Metaphysics Lambda into Portuguese.

Trata-se de tradução do Hípias Maior de Platão para o Português, com algumas notas de elucidação e justificação das opções.

I discuss what Aristotle means when he say that scientific demonstration must proceed from necessary principles. I argue that, for Aristotle, scientific demonstration should not be reduced to sound deduction with necessary premises. Scientific demonstration ultimately depends on the fully appropriate explanatory factor for a given explanandum. This explanatory factor is what makes the explanandum what it is. Consequently, this factor is also unique. When Aristotle says that demonstration must proceed from necessary principles, he means that each demonstration requires the (...) principle that is the necessary one for the fully appropriate explanation of its explanandum. This picture also provides a key to understand Aristotle's thesis that scientific explanation depends on essences: it is the essence of the attribute to be explained that should be stated as the fully appropriate explanatory factor. (shrink)

Paul Guyer is well known for defending the claim that freedom, understood as the capacity to set ends, is Kant’s fundamental value. In contrast, I have developed a reading of Kant’s ethics that places autonomy and community at the heart of Kant’s ethics. At the heart of my account is a conception of autonomy understood as what I call the capacity for sovereignty. I argue that these two positions can be made compatible. To do this involves making a distinction between (...) the concepts of dignity and value and arguing that although autonomy, understood as the capacity for sovereignty, is the source of the dignity of humanity, this is compatible with the claim that the ultimate value for Kant is freedom understood as the capacity to set ends. To explain how this is possible I appeal to Wilfrid Sellars Kantian account of the moral point of view in Science and Metaphysics. (shrink)

My object is Aristotle's discussion of principle of non-contradiction in the first stretch of Metaphysics IV.4. My main focus rests on the connections between Aristotle's discussion of the principle and some key notions of his (explicit or implied) semantics.

There are two standard conceptions of the functioning of and rationale for the diachronic will, i.e., for an agent's capacity to settle on her future conduct in advance. According to the pragmatic-instrumentalist view, the diachronic will benefits us by increasing the long-term satisfaction of our rational preferences. According to the cognitive view, it benefits us by satisfying our standing desire for self-knowledge and self-understanding. Contrary to these views, I argue for a constitutive view of the diachronic will: the rationale for (...) it is that it makes possible to engage in activities with a radically novel temporal structure, activities that are not merely continuous over time, but temporally integrated and unified. These activities are essential to our form of life and to our existence as temporally unified agents. The instrumental and cognitive benefits, if any, are merely secondary to the ontological ones. (shrink)

I have two aims in this paper. First, I argue that, in Aristotle’s theory of the four causes, there is a basic and common feature by which all causes are causes: they all work in a triadic framework in which they explain why a given attribute holds of a given underlying thing. Secondly, I argue against a version of “compatibilism” according to which each kind of cause is complete in its own domain and does not compete with any other kind. (...) I claim that there are priority relations according to which some kinds of cause are subordinated to others, even if these relations do not hold in every cases. (shrink)

In this paper, we develop an impure somatic theory of emotion, according to which emotions are constituted by the integration of bodily perceptions with representations of external objects, events, or states of affairs. We put forward our theory by contrasting it with Prinz's pure somatic theory, according to which emotions are entirely constituted by bodily perceptions. After illustrating Prinz's theory and discussing the evidence in its favor, we show that it is beset by serious problems—i.e., it gets the neural correlates (...) of emotion wrong, it isn't able to distinguish emotions from bodily perceptions that aren't emotions, it cannot account for emotions being directed towards particular objects, and it mischaracterizes emotion phenomenology. We argue that our theory accounts for the empirical evidence considered by Prinz and solves the problems faced by his theory. In particular, we maintain that our theory gives a unified and principled account of the relation between emotions and bodily perceptions, the intentionality of emotions, and emotion phenomenology. (shrink)

This paper criticizes phenomenal conservatism––the influential view according to which a subject S’s seeming that P provides S with defeasible justification for believing P. I argue that phenomenal conservatism, if true at all, has a significant limitation: seeming-based justification is elusive because S can easily lose it by just reflecting on her seemings and speculating about their causes––I call this the problem of reflective awareness. Because of this limitation, phenomenal conservatism doesn’t have all the epistemic merits attributed to it by (...) its advocates. If true, phenomenal conservatism would constitute a unified theory of epistemic justification capable of giving everyday epistemic practices a rationale, but it wouldn’t afford us the means of an effective response to the sceptic. Furthermore, phenomenal conservatism couldn’t form the general basis for foundationalism. (shrink)

The analytical notion of ‘scientific style of reasoning’, introduced by Ian Hacking in the middle of the 1980s, has become widespread in the literature of the history and philosophy of science. However, scholars have rarely made explicit the philosophical assumptions and the research objectives underlying the notion of style: what are its philosophical roots? How does the notion of style fit into the area of research of historical epistemology? What does a comparison between Hacking’s project on styles of thinking and (...) other similar projects suggest? My aim in this paper is to answer these questions. Hacking has denied that his project of styles of thinking falls into the field of historical epistemology. I shall challenge his remark by tracing out the connections of the notion of style with historical epistemology and, more in general, with a tradition of thought born in France in the beginning of twentieth-century. (shrink)

I discuss Aristotle's treatment of essence and definition in Metaphysics VII.4. I argue that it is coherent and perfectly in accord with its broader context. His discussion in VII.4 offers, on the one hand, minimal criteria for what counts as definition and essence for whatever kind of object, but also, on the other hand, stronger criteria for a primary sort of definition and essence—and thereby it serves the interest of book VII in pointing to the explanatory power of the essence (...) of composite substances. (shrink)

I examine Aristotle’s definition of scientific knowledge in Posterior Analytics 71b 9-12 and try to understand how it relates to the sophistical way of knowing and to "kata sumbebekos knowledge". I claim that scientific knowledge of p requires knowing p by its appropriate cause, and that this appropriate cause is a universal (katholou) in the restricted sense Aristotle proposes in 73b 26-27 ff., i.e., an attribute coextensive with the subject (an extensional feature) and predicated of the subject in itself (an (...) intensional feature). Kata sumbebekos knowledge, on the other hand, can occur even when the predicate of a conclusion is coextensive with its subject and is proved by a convertible meson which is not the most appropriate from an explanatory standpoint. (shrink)

In this chapter, I shall consider a number of connections between various ideas of the theory of styles of reasoning and the issue of the contingency and inevitability of science. By ‘contingency issue’ it is meant the question as to whether the history of a particular branch of our science could have taken a different route and provided results incompatible with those of our actual science. Apart from Hacking’s recent comments, the discussions on the contingency issue have not involved the (...) notion of style of reasoning. I will fill this gap in the literature by drawing some important implications for the issue of contingency from the theory of styles of reasoning that I have developed so far. I shall address four fundamental questions. First of all, in the next section I shall discuss to which extent the emergence of styles of reasoning at a certain point of history is a contingent circumstance. In the following section I shall ask whether the endurance of styles of reasoning was inevitable by tackling the connected question as to why the styles are long lasting. Afterwards, I shall focus on the growth of knowledge by dealing with questions such as: if a certain style of reasoning continues to be employed and if Q is a ‘live question’, is science bound to converge on a single answer to Q? Finally, on the basis of my previous reflections I shall look into the question of the convergence of science in the long run. The answers to these questions will rely on some basic assumptions of the theory of style of reasoning and imply a picture of the evolution of sciences in which both contingency and inevitability play a key role. (shrink)

Constitutivism argues that the source of the categorical force of the norms of rationality and morality lies in the constitutive features of agency. A systematic failure to be guided by these norms would amount to a loss or lack of agency. Since we cannot but be agents, we cannot but be unconditionally guided by these norms. The constitutivist strategy has been challenged by David Enoch. He argues that our participation in agency is optional and thus cannot be a source of (...) categorical demands. In this paper, I defend the viability of constitutivism by showing that agency is indeed a special ‘inescapable’ enterprise. Agency has the largest jurisdiction, and it is closed under rational assessment. This inescapability does not exempt constitutivism from raising the question whether agents have reason to be agents, but this question has to be taken up within agency. If this question is answered affirmatively, then—I argue—the criteria of practical correctness are self-ratifying in a non-circular way. This is sufficient to show the viability of the constitutivist strategy. Whether agents have conclusive reasons to be agents, however, is a matter to be addressed in the terms of particular versions of constitutivism. (shrink)

I review recent work on Phenomenal Conservatism, the position introduced by Michael Huemer according to which if it seems that P to a subject S, in the absence of defeaters S has thereby some degree of justification for believing P.

A filosofia da natureza de Aristóteles muitas vezes é apresentada como um capítulo inteiramente ultrapassado na história do pensamento: um “finalismo antiquado”, antropocêntrico, avesso à mensuração exata das condições materiais subjacentes aos fenômenos. Essa perspectiva, no entanto, é inadequada: não atenta para o papel relevante que Aristóteles atribui à matéria na explicação dos fenômenos naturais, assim como não atina com o real significado da teleologia aristotélica. Na contra-mão dessa perspectiva apressada, procuramos mostrar que, no cerne da filosofia aristotélica da natureza, (...) entendida como uma teleologia, encontra-se a idéia de que os seres naturais definem-se por uma tendência intrínseca à auto-preservação. É por essa tendência que a forma de cada ser natural governa teleologicamente sua matéria. (shrink)

In this paper Lucas suggests that many of his critics have not read carefully neither his exposition nor Penrose’s one, so they seek to refute arguments they never proposed. Therefore he offers a brief history of the Gödelian argument put forward by Gödel, Penrose and Lucas itself: Gödel argued indeed that either mathematics is incompletable – that is axioms can never be comprised in a finite rule and so human mind surpasses the power of any finite machine – or there (...) exist absolutely unsolvable diophantine problems, and he suggest that the second disjunct is untenable; on the other side, Penrose proposed an argument similar to Lucas’ one but making use of Turing’s theorem. Finally Lucas exposes again his argument and considers some of the most important objections to it. (shrink)

Coherentism in epistemology has long suffered from lack of formal and quantitative explication of the notion of coherence. One might hope that probabilistic accounts of coherence such as those proposed by Lewis, Shogenji, Olsson, Fitelson, and Bovens and Hartmann will finally help solve this problem. This paper shows, however, that those accounts have a serious common problem: the problem of belief individuation. The coherence degree that each of the accounts assigns to an information set (or the verdict it gives as (...) to whether the set is coherent tout court) depends on how beliefs (or propositions) that represent the set are individuated. Indeed, logically equivalent belief sets that represent the same information set can be given drastically different degrees of coherence. This feature clashes with our natural and reasonable expectation that the coherence degree of a belief set does not change unless the believer adds essentially new information to the set or drops old information from it; or, to put it simply, that the believer cannot raise or lower the degree of coherence by purely logical reasoning. None of the accounts in question can adequately deal with coherence once logical inferences get into the picture. Toward the end of the paper, another notion of coherence that takes into account not only the contents but also the origins (or sources) of the relevant beliefs is considered. It is argued that this notion of coherence is of dubious significance, and that it does not help solve the problem of belief individuation. (shrink)