No Órganon Aristóteles descreve alguns esquemas dedutivos nos quais a presença de inconsistências não acarreta a trivialização da teoria lógica envolvida. Esta tese é corroborada por três diferentes situações teóricas estudadas por ele, as quais são apresentadas neste trabalho. Analizamos o esquema de inferência utilizado por Aristóteles no Protrepticus e o método de demonstração indireta para os silogismos categóricos. Ambos os métodos exemplificam como Aristóteles emprega estratégias de redução ao absurdo logicamente clássicas. Na sequência, discutimos os silogismos válidos a partir (...) de premissas opostas (contrárias e contraditórias) estudadas pelo Estagirita no Analytica Priora (B15). De acordo com o autor, os seguintes silogismos são válidos a partir de premissas opostas, nos quais letras latinas minúsculas denotam termos como sujeito e predicado, enquanto que letras latinas maiúsculas denotam proposições categóricas tal como na notação tradicional: (i) na segunda figura, Eba,Aba ` Eaa (Cesare), Aba, Eba ` Eaa (Camestres), Eba, I ba ` Oaa (Festino), e Aba,Oba ` Oaa (Baroco); (ii) na terceira, Eab,Aab ` Oaa (Felapton), Oab,Aab ` Oaa (Bocardo) e Eab, Iab ` Oaa (Ferison). Por fim, discutimos a passagem do Analytica Posteriora (A11) no qual Aristóteles enuncia que o Princípio de Não-Contradição não é, em geral, pressuposto de toda demonstração (silogismo científico), mas apenas daquelas nas quais a conclusão deve ser provada a partir do Princípio; o Estagirita enuncia que se um silogismo da primeira figura tiver o termo maior consistente, os outros termos da demonstração podem ser separadamente inconsistentes. Estes resultados permitem-nos propor uma interpretação de sua teoria dedutiva como uma teoria paraconsistente lato sensu. Primeiramente, efetuamos uma análise hermenêutica, avaliando seu significado lógico e a correlação desses resultados com outros aspectos da filosofia de Aristóteles. Em segundo lugar, consignamos uma interpretação dos silogismos aristotélicos a partir de premissas opostas à luz dos antilogismos propostos por Christine Ladd-Franklin em 1883, e da demonstração aristotélica com termos inconsistentes nas lógicas paraconsistentes Cn, 1 n !, introduzidas por da Costa em 1963. Esses dois aspectos não parecem ter sido ainda detalhadamente analisados na literatura. DOI:10.5007/1808-1711.2010v14n1p71. (shrink)
S. Jakowski introduced the discussive prepositional calculus D 2as a basis for a logic which could be used as underlying logic of inconsistent but nontrivial theories (see, for example, N. C. A. da Costa and L. Dubikajtis, On Jakowski's discussive logic, in Non-Classical Logic, Model Theory and Computability, A. I. Arruda, N. C. A da Costa and R. Chuaqui edts., North-Holland, Amsterdam, 1977, 37–56). D 2has afterwards been extended to a first-order predicate calculus and to a higher-order logic (...) (cf. the quoted paper). In this paper we present a natural version of D 2, in the sense of Jakowski and Gentzen; as a consequence, we suggest a new formulation of the discussive predicate calculus (with equality). A semantics for the new calculus is also presented. (shrink)
In this paper we study the systemsP andP * (see Arruda and da Costa,O paradoxo de Curry-Moh Shaw-Kwei, Boletim da Sociedade Matemtica de São Paulo 18 (1966)) and some related systems. In the last section, we prove that certain set theories havingP andP * as their underlying logics are non-trivial.
Costa uses a symbolic metaphor to 8-10 year-olds with ‘Mr. Potato Head’ to show the value of meaning and how to be unique and true to oneself (metaphysics).
James Van Cleve has argued that Kant’s Transcendental Deduction of the categories shows, at most, that we must apply the categories to experience. And this falls short of Kant’s aim, which is to show that they must so apply. In this discussion I argue that once we have noted the differences between the first and second editions of the Deduction, this objection is less telling. But Van Cleve’s objection can help illuminate the structure of the B Deduction, and it suggests (...) an interesting reason why the rewriting might have been thought necessary. (shrink)
John McDowell’s original motivation of disjunctivism occurs in the context of a problem regarding other minds. Recent commentators have insisted that McDowell’s disjunctivism should be classed as an epistemological disjunctivism about epistemic warrant, and distinguished from the perceptual disjunctivism of Hinton, Snowdon and others. In this paper I investigate the relation between the problem of other minds and disjunctivism, and raise some questions for this interpretation of McDowell.
Quassim Cassam has recently defended a perceptual model of knowledge of other minds: one on which we can see and thereby know that another thinks and feels. In the course of defending this model, he addresses issues about our ability to think about other minds. I argue that his solution to this 'conceptual problem' does not work. A solution to the conceptual problem is necessary if we wish to explain knowledge of other minds.
Scepticism is sometimes expressed about whether there is any interesting problem of other minds. In this paper I set out a version of the conceptual problem of other minds which turns on the way in which mental occurrences are presented to the subject and situate it in relation to debates about our knowledge of other people's mental lives. The result is a distinctive problem in the philosophy of mind concerning our relation to other people.
We are able to think of empirical objects as capable of existing unperceived. What explains our grasp of this conception of objects? In this paper I examine the claim that experience explains our understanding of objects as capable of existing unperceived with reference to Kant’s Critique of Pure Reason. I argue that standard accounts of experience’s explanatory role are unsatisfactory, but that an alternative account can be extracted from the first Critique – one which relies on Kant’s transcendental idealism.
This article discusses Philip Pettit’s neo-republicanism in light of the criterion of self-sustenance: the requirement that a political theory be capable of serving as a self-sustaining public philosophy for a pluralist democracy. It argues that this criterion can only be satisfied by developing an adequate politics of virtue. Pettit’s theory is built around the notion of freedom as non-domination, and he does not say much about the virtues of citizens or the policies the state may employ to encourage their development. (...) In order to explain the motivation to comply with republican laws that promote non-domination, Pettit relies on the phenomenon of civility and the mechanism of the intangible hand. But to understand what underlies an adequate level of robust civility one needs to focus on the more basic phenomenon of personal virtue. Policies that aim to promote non-domination should take into account the need to cultivate virtue among citizens, as well as the full range of conditions that favor its exercise. (shrink)
This paper proposes a new, stronger version of the cluster theory of proper names. It introduces a meta-identifying rule that can establish a cluster's main descriptions and explain how they must be satisfied in order to allow the application of a proper name. At the same time, it preserves some main insights of the causal-historical view. With the resulting rule we can not only give a more detailed reply to the counter-examples to descriptivism, but also explain the informative contents of (...) proper names and why they are rigid designators in contrast with descriptions.1. (shrink)
One of the central elements of John Rawls’ argument in support of his two principles of justice is the intuitive normative ideal of citizens as free and equal. But taken in isolation, the claim that citizens are to be treated as free and equal is extremely indeterminate, and has virtually no clear implications for policy. In order to remedy this, the two principles of justice, together with the stipulation that citizens have basic interests in developing their moral capacities and pursuing (...) their conceptions of the good life, are meant to provide a more precise interpretation of what is involved in treating citizens as free and equal. Rawls’ critics, however, have argued that satisfying the two principles of justice is not the most appropriate or plausible way to respect the status of citizens as free and equal. In relation to this debate, the present paper has two aims. The first is to examine Rawls’ account of the type of freedom that a just society must guarantee equally to its citizens. I will argue that those who think of Rawls as a theorist of freedom as non-interference are mistaken, because his notion of liberty resembles in important respects the republican notion of freedom as non-domination. Second, I will consider the extent to which Rawls’ principles of justice successfully protect the freedom as non-domination of all citizens so as to effectively treat them as free and equal. (shrink)
The prima facie heterogeneity between psychical and physical phenomena seems to be a serious objection to psychoneural identity thesis, according to many authors, from Leibniz to Popper. It is argued that this objection can be superseded by a different conception of consciousness. Consciousness, while being conscious of something, is always unconscious of itself . Consciousness of being conscious is not immediate, it involves another, second-order, conscious state. The appearance of mental states to second-order consciousness does not reveal their true nature. (...) Psychoneural identity can thus be considered a valid hypothesis. Related views of Kant, Freud, Shaffer, Bunge and others are considered. “Naive psychical realism” is criticised. Consciousness of mental events is considered as the result of the action of a cerebral system that observes the neural events hypothetically identical to mental events. The theory combines a materialist view with a due consideration of subjective experience. (shrink)
1. Introduction The readiness potential was found to precede voluntary acts by about half a second or more (Kornhuber & Deecke, 1965). Kornhuber (1984) discussed the readiness potential in terms of volition, arguing that it is not the manifestation of an attentional processes. Libet discussed it in relation to consciousness and to free will (Libet et al. 1983a; 1983b; Libet, 1985, 1992, 1993). Libet asked the following questions. Are voluntary acts initiated by a conscious decision to act? Are the physiological (...) facts compatible with the belief that free will determines our voluntary acts? What is the role of consciousness in voluntary action? In this paper I will discuss these questions and the answers that Libet gave to them. (shrink)
This article examines the relevance of a theory of the multinational state for the evaluation of claims for self-determination and secession. Considerations of ?ethnocultural justice? imply that the recognition of the multinational character of a state ? or the granting of some of the minority nations' demands ? is a matter of justice. If these requirements are not met, secession could be justified. Indeed, if secession needs a just cause (as it has been argued), a failure to build a truly (...) multinational arrangement can be a valid reason for a minority nation to secede. An approach like the one proposed would also contribute to the resolution of some of the key problems of the three main theories of secession and their appeals to nationalism, choice and remedial rights. (shrink)
Claims that necessary and sufficient conditions are not converse relations are discussed, as well as the related claim that If A, then B is not equivalent to A only if B . The analysis of alleged counterexamples has shown, among other things, how necessary and sufficient conditions should be understood, especially in the case of causal conditions, and the importance of distinguishing sufficient-cause conditionals from necessary-cause conditionals. It is concluded that necessary and sufficient conditions, adequately interpreted, are converse relations in (...) all cases. (shrink)
This study surveys debates on citizenship, the state, and the bases of political stability. The survey begins by presenting the primary sense of 'citizenship' as a legal status and the question of the sorts of political communities people can belong to as citizens. (Multi)nation-states are suggested as the main site of citizenship in the contemporary world, without ignoring the existence of alternative possibilities. Turning to discussions of citizen identity, the study shows that some of the discussion is motivated by a (...) perceived need for citizens to have a sense of political belonging, on the assumption that such a sense promotes political activity and has other personal and social benefits. But there are serious problems with the strategy of understanding the relevant sense of belonging in terms of identification with the nation-state. The study explores a more promising way to generate this sense of belonging. First, societies should function, to a sufficiently high degree, in accord with political principles of justice and democratic decision making. Second, there should be a general consensus on political principles among citizens, as well as high levels of engagement in democratic deliberation. (shrink)
The recent discovery of a mirror neuron system sets a challenge for a philosophy of experience such as phenomenology, because in humans and monkeys the mirror system seems to transform seen actions into an inner representation of these actions. This paper tries to outline the guidelines of a transcendental-phenomenological analysis of alterity, different from empirical research. The transcendental research must provide a criterion for interpreting the results of empirical science. On this basis the paper compares the phenomenological analysis of alterity (...) with some results of neuroscientific research. It is argued that Edmund Husserl presents an analysis that enables us to avoid misinterpretations of the role and function of the mirror neuron system. (shrink)
Peter Goldie has argued for a virtue theory of art, analogous to a virtue theory of ethics, one in which the skills and dispositions involved in the production and appreciation of art are virtues and not simply mere skills. In this note I highlight a link between the appreciation of art and its production, and explore the implications of such a link for a virtue theory of art.
In this paper an improved formulation of the classical tripartite view of knowledge is proposed and defended. This formulation solves Gettier's problem by making explicit what is concealed by the symbolic version of the tripartite definition, namely, the perspectival context in which concrete knowledge claims are evaluated.
We offer a probabilistic model of rational consequence relations (Lehmann and Magidor, 1990) by appealing to the extension of the classical Ramsey–Adams test proposed by Vann McGee in (McGee, 1994). Previous and influential models of non-monotonic consequence relations have been produced in terms of the dynamics of expectations (Gärdenfors and Makinson, 1994; Gärdenfors, 1993).Expectation is a term of art in these models, which should not be confused with the notion of expected utility. The expectations of an agent are some form (...) of belief weaker than absolute certainty. Our model offers a modified and extended version of an account of qualitative belief in terms of conditional probability, first presented in (van Fraassen, 1995). We use this model to relate probabilistic and qualitative models of non-monotonic relations in terms of expectations. In doing so we propose a probabilistic model of the notion of expectation. We provide characterization results both for logically finite languages and for logically infinite, but countable, languages. The latter case shows the relevance of the axiom of countable additivity for our probability functions. We show that a rational logic defined over a logically infinite language can only be fully characterized in terms of finitely additive conditional probability. (shrink)
An improvement on Horwich's so-called pseudo-proof of Russell's principle of induction is offered, which, we believe, avoids certain objections to the former. Although strictly independent of our other work in this area, a connection can be made and in the final section we comment on this and certain questions regarding rationality, etc.
An extended examination of Libet's works led to a comprehensive reinterpretation of his results. According to this reinterpretation, the Minimum Train Duration of electrical brain stimulation should be considered as the time needed to create a brain stimulus efficient for producing conscious sensation and not as a basis for inferring the latency for conscious sensation of peripheral origin. Latency for conscious sensation with brain stimulation may occurafterthe Minimum Train Duration. Backward masking with cortical stimuli suggests a 125-300 ms minimum value (...) for the latency for conscious sensation of threshold skin stimuli. Backward enhancement is not suitable for inferring this latency. For determining temporal relations between stimuli that correspond to subjects' reports, theendof cerebral Minimum Train Duration should be used as reference, rather than its onset. Results of coupling peripheral and cortical stimuli are explained by a latency after the cortical Minimum Train Duration, having roughly the same duration as the latency for supraliminal skin stimuli. Results of coupling peripheral stimuli and stimuli to medial lemniscus (LM) are explained by a shorter LM latency and/or a longer peripheral latency. This interpretation suggests a 230 ms minimum value for the latency for conscious sensation of somatosensory near-threshold stimuli. The backward referral hypothesis, as formulated by Libet, should not be retained. Long readiness potentials preceding spontaneous conscious or nonconscious movements suggest that both kinds of movement are nonconsciously initiated. The validity of Libet's measures of W and M moments (Libet et al., 1983a) is questionable due to problems involving latencies, training, and introspective distinction of W and M. Veto of intended actions may be initially nonconscious but dependent on conscious awareness. (shrink)
Earlier, we have studied computations possible by physical systems and by algorithms combined with physical systems. In particular, we have analysed the idea of using an experiment as an oracle to an abstract computational device, such as the Turing machine. The theory of composite machines of this kind can be used to understand (a) a Turing machine receiving extra computational power from a physical process, or (b) an experimenter modelled as a Turing machine performing a test of a known (...) physical theory T. (shrink)
How to accept a conditional? F. P. Ramsey proposed the following test in (Ramsey 1990).(RT) If A, then B must be accepted with respect to the current epistemic state iff the minimal hypothetical change of it needed to accept A also requires accepting B.
The word 'consciousness' is used in different ways, but not all of these uses reflect clear concepts or should be retained in technical discussions. In his target article Christian de Quincey (2006) notes that confusion about consciousness is widespread and sets out to distinguish two main meanings of the word. To my mind, however, his treatment of the subject is itself confused and the proposed distinction misses the point.
An appropriately unprejudiced logical investigation of causation as a type of implication relation is undertaken. The implication delineated is bounded syntactically. The developing argument then leads to a very natural process analysis, which demonstrably captures the established syntactical features. Next relevantly-based semantics for the resulting logical theory are adduced, and requisite adequacy results delivered. At the end of the tour, further improvements are pointed out, and the attractive terrain beyond present developments is glimpsed.
This paper aims at showing that Hobbes's theory of language, which allows men to communicate among themselves like no other animal species, is an importante factor in the integration of modern states. Both his nominalism and the fact that he considers language previous to reason play a role in the formation of social groups. This leads him, as Johnston points out, to make political order depend upon linguistic order. In consequence, Hobbes aims at building a political philosophy by introducing a (...) suitable vocabulary and setting basic propositions from which to deduce valid conclusions, proceding more geometrico . He also points out the importance of language for men to emerge from the state of nature and to draw a compact for peace and security. He also stresses the relation between language and power. Biblical references are included to reinforce the role of language in society, It is also shown that occasionally language may be a disgregating factor. Examples are put rather to show the integrating force of language. (shrink)
In his thesis Para uma Teoria Geral dos Homomorfismos (1944), the Portuguese mathematician José Sebastiāo e Silva constructed an abstract or generalized Galois theory, that is intimately linked to F. Klein's Erlangen Program and that foreshadows some notions and results of today's model theory; an analogous theory was independently worked out by M. Krasner in 1938. In this paper, we present a version of the theory making use of tools which were not at Silva's disposal. At the same time, we (...) tried to keep in mind, so much as possible, the gist of his standpoint. (shrink)
The paper studies first order extensions of classical systems of modal logic (see (Chellas, 1980, part III)). We focus on the role of the Barcan formulas. It is shown that these formulas correspond to fundamental properties of neighborhood frames. The results have interesting applications in epistemic logic. In particular we suggest that the proposed models can be used in order to study monadic operators of probability (Kyburg, 1990) and likelihood (Halpern-Rabin, 1987).
The article focuses on representing different forms of non-adjunctive inference as sub-Kripkean systems of classical modal logic, where the inference from □A and □B to □A∧B fails. In particular we prove a completeness result showing that the modal system that Schotch and Jennings derive from a form of non-adjunctive inference in (Schotch and Jennings, 1980) is a classical system strictly stronger than EMN and weaker than K (following the notation for classical modalities presented in Chellas, 1980). The unified semantical characterization (...) in terms of neighborhoods permits comparisons between different forms of non-adjunctive inference. For example, we show that the non-adjunctive logic proposed in (Schotch and Jennings, 1980) is not adequate in general for representing the logic of high probability operators. An alternative interpretation of the forcing relation of Schotch and Jennings is derived from the proposed unified semantics and utilized in order to propose a more fine-grained measure of epistemic coherence than the one presented in (Schotch and Jennings, 1980). Finally we propose a syntactic translation of the purely implicative part of Jaśkowski's system D2 into a classical system preserving all the theorems (and non-theorems) explicilty mentioned in (Jaśkowski, 1969). The translation method can be used in order to develop epistemic semantics for a larger class of non-adjunctive (discursive) logics than the ones historically investigated by Jaśkowski. (shrink)
An important trend in contemporary epistemology centers on elaborating an old idea of pragmatist pedigree: theory selection (and in general the process of changing view and fixing beliefs) presupposes epistemic values. This article focuses on analyzing the case where epistemic values are indeterminate or when the sources of valuation are multiple (epistemic values like coherence and simplicity need not order options in compatible ways). According to the theory that thus arises epistemic alternatives need not be fully ordered by an underlying (...) notion of information-value and therefore the usual economic techniques of optimization cannot be applied in order to compute optimal contractions. But in cases of this sort it is still rational to maximize, i.e. to deem an option as choosable when it is not known to be worse that any other. We present here basic results about a notion of liberal contraction based on maximizing quasi-orderings. This requires the previous solution of some open problems in the theory of rational choice functions, namely a full characterization of choice functions rationalizable in terms of maximization of quasi-transitive relations. We conclude by discussing the problem of what is the adequate feasible set for calculating maximizing solutions for contraction problems and by considering the epistemological roots of some counterexamples against the most fundamental axioms on choice functions (like α). While the first part of the paper shows how economic insights can be used to improve our understanding of the principles of belief formation and change, this final section reverses this strategy by showing the utility of epistemological insights and techniques for providing invariance conditions capable of regulating the applicability of the pure principles of choice. (shrink)
In this work, we propose a computational approach to the triadic model of Peircean semiosis (meaning processes). We investigate theoretical constraints about the feasibility of simulated semiosis. These constraints, which are basic requirements for the simulation of semiosis, refer to the synthesis of irreducible triadic relations (SignâObjectâInterpretant). We examine the internal organization of the triad SâOâI, that is, the relative position of its elements and how they relate to each other. We also suggest a multi-level approach based on self-organization principles. (...) In this context, semiosis is described as an emergent process. Nevertheless, the term âemergenceâ is often used in a very informal way in the so called âemergentâ computation, without clear explanations and/or definitions. In this paper, we discuss in some detail the meaning of the theoretical terms âemergenceâ and âemergentâ, showing how such an analysis can lead to improvements of the algorithm proposed. (shrink)
A critical review of what I see as a controversial interpretation of the nature and aims of Darwin’s rhetorical strategy and a narrow and controversial naturalist manifesto.
This paper illustrates the main features of Luigi Ferrajoli’s theoretical approach to law, as they are developed in his Principia Juris . These include his opposition to the traditional perspective of natural law; his anti-cognitivist orientation; and, finally, his fundamentally normative approach. Among the numerous problems discussed in Ferrajoli’s compendious book, the paper focuses on his definition of constitutional democracy. In particular, the paper discusses the way in which Ferrajoli defines the complementarity between democracy and rights; Ferrajoli’s own criticism of (...) T. H. Marshall’s idea of citizenship; and the importance that the distinction between ‘decidable’ and ‘non-decidable’ rights have in Ferrajoli’s own system. Other issues of interests that are briefly discussed include the constitutionalisation of private law, and the defence of different kinds of liberty-rights. (shrink)
