Ao defender, nos Princípios matemáticos de filosofia natural, a existência de uma força de gravitação universal, Newton desencadeou uma onda de dúvidas e objeções filosóficas. Suas próprias declarações sobre a natureza da gravitação não são facilmente interpretáveis como formando um conjunto consistente de opiniões. Por um lado, logo após fornecer as três definições de "quantidades de forças centrípetas" (Defs. 6-8), Newton observa que está tratando tais forças "matematicamente", sem se pronunciar sobre sua realidade física. Mas, por outro lado, no Escólio (...) Geral inserido no final da segunda edição do livro, Newton diz que foi capaz de "explicar" vários fenômenos de movimento por meio da força de gravidade - que ele mostrou ser um tipo de força centrípeta -, embora não tivesse ainda conseguido explicar a causa dessa força. Uma interpretação plausível dessas últimas afirmações é que Newton acreditava que pôde inferir, a partir dos fenômenos, a existência da força de gravidade, enquanto agente causal real de certos movimentos, mas que ainda não havia tido sucesso em descobrir a causa dessa causa. O objetivo principal do presente artigo não é aprofundar a análise histórica das declarações de Newton, mas examinar como essa questão se insere no debate mais geral sobre o estatuto epistemológico das hipóteses científicas que transcendem a experiência imediata. Segundo a posição defendida, entre muitos outros, por John Locke, tais hipóteses devem ser interpretadas como tentativas legítimas de descrever aspectos inobserváveis da realidade. Em contraste com isso, no caso específico das hipóteses sobre forças - de gravitação ou quaisquer outras -, George Berkeley argumentou vigorosamente a favor de sua interpretação como meros artifícios teóricos úteis às "demonstrações matemáticas" na ciência da mecânica. Ao longo da análise das vantagens e desvantagens filosóficas dessas posições opostas, indica-se aqui que, embora a interpretação realista pareça fazer mais justiça ao desenvolvimento real da física após os Princípios matemáticos, a interpretação instrumentalista de Berkeley tem o mérito filosófico inegável de representar uma adesão mais firme ao empirismo, que é, de um modo ou de outro, valorizado por ambas as partes envolvidas na disputa sobre a natureza da gravitação. Newton's defence, in the Principia, of the existence of a universal force of gravity immediately gave rise to a wave of philosophical doubts and objections. His own remarks on the nature of gravitation are not easily amenable of a consistent, uniform interpretation. This paper begins by reviewing briefly these remarks. Its primary objective is, however, to examine how this important scientific issue contributed to demarcate two main epistemological positions on the status of scientific hypotheses transcending immediate experience. In Newton's time, two exponents of these positions were, respectively, Locke and Berkeley. Intriguingly, Newton fuelled both the Berkeleyan, instrumentalist interpretation, and the Lockean, realist interpretation. On the one hand, immediately after offering the definitions of "quantities of centripetal forces" (Definitions 6-8), he warned that he was treating these forces "mathematically", without pronouncing on its physical status. This remark lends support to Berkeley's anti-realist interpretation of forces, as Berkeley himself was keen to point out. But in the General Scholium, at the end of the book, Newton declared that he could "explain" certain important phenomena of motion by the force of gravity, although he had not yet been able to explain the cause of this force, adding, famously, that he would "feign no hypotheses" about this issue. A natural, realist interpretation of this statement is that Newton believed that he could infer, from the phenomena, the existence of gravity, as a real, causal physical agent, but that he had not yet succeeded in discovering the cause of this cause. In discussing the shortcomings and advantages of these opposing views, we indicate that although the realist interpretation appears to do more justice to the actual development of physics after the Principia, Berkeley's interpretation has the philosophical merit of representing a firmer adherence to empiricism, a position valued, in one way or another, by all parties involved in the dispute on the nature of gravitation. (shrink)

http://dx.doi.org/10.5007/1808-1711.2008v12n1p49 The aim of this article is to offer a rejoinder to an argument against scientific realism put forward by van Fraassen, based on theoretical considerations regarding microphysics. At a certain stage of his general attack to scientific realism, van Fraassen argues, in contrast to what realists typically hold, that empirical regularities should sometimes be regarded as “brute facts”, which do not ask for explanation in terms of deeper, unobservable mechanisms. The argument from microphysics formulated by van Fraassen is based (...) on the claim that in microphysics the demand for explanation leads to a demand for the so-called hidden-variable theories, which “runs contrary to at least one major school of thought in twentieth-century physics”. It is shown here that this argument does not represent an insurmountable obstacle to scientific realism, not even when a series of important theoretical and experimental results against hidden-variable theories — and not merely a conflict with a certain school of thought—is taken into account. (shrink)

This paper discusses an argument for scientific realism put forward by Anthony Quinton in The Nature of Things. The argument – here called the controlled continuity argument – seems to have received no attention in the literature, apparently because it may easily be mistaken for a better-known argument, Grover Maxwell’s “argument from the continuum”. It is argued here that, in point of fact, the two are quite distinct and that Quinton’s argument has several advantages over Maxwell’s. The controlled continuity argument (...) is also compared to Ian Hacking’s “argument from coincidence”. It is pointed out that both arguments are to a large extent independent from considerations about high-level scientific theories, and that both are abductive arguments at the core. But these similarities do not dilute an important difference related to the fact that Quinton’s argument cleverly seeks to anchor belief in unobservable entities in realism about ordinary objects, which is a position shared by most contemporary scientific anti-realists. (shrink)

The aim of this article is to offer a rejoinder to an argument against scientific realism put forward by van Fraassen, based on theoretical considerations regarding microphysics. At a certain stage of his general attack to scientific realism, van Fraassen argues, in contrast to what realists typically hold, that empirical regularities should sometimes be regarded as “brute facts”, which do not ask for explanation in terms of deeper, unobservable mechanisms. The argument from microphysics formulated by van Fraassen is based on (...) the claim that in microphysics the demand for explanation leads to a demand for the so-called hidden-variable theories, which “runs contrary to at least one major school of thought in twentieth-century physics”. It is shown here that this argument does not represent an insurmountable obstacle to scientific realism, not even when a series of important theoretical and experimental results against hidden-variable theories — and not merely a conflict with a certain school of thought—is taken into account. (shrink)

http://dx.doi.org/10.5007/1808-1711.2012v16n2p229 Tanto no Tratado da Natureza Humana como na Investigação sobre o Entendimento Humano , Hume mostra-se convencido de que “não há acaso no mundo”, e que “aquilo que o vulgo chama de acaso não passa de uma causa secreta e escondida”. Essa tese desempenha papel crucial em sua análise do livre-arbítrio e, conseguintemente, da responsabilidade moral; é também um elemento importante em sua discussão sobre os milagres. No entanto, o próprio Hume ofereceu, no Tratado , um argumento convincente para (...) mostrar que o princípio de causalidade, segundo o qual tudo o que começa a existir tem uma causa, não pode ser conhecido a priori , por intuição ou demonstração. Logo, essa “opinião tem necessariamente de provir da observação e experiência”. O presente trabalho examina essa tese, mostrando, inicialmente, qual era a proposta de Hume para fundar na experiência o princípio de causalidade, e depois qual, de fato, teria sido o mais robusto fundamento para esse princípio: a mecânica newtoniana. Explica-se, por fim, como esse fundamento empírico indireto e o próprio argumento de Hume foram solapados pela física quântica, no século XX. (shrink)

Both in the Treatise of Human Nature and in the Enquiry concerning Human Understanding, Hume defends that “there is no chance in the world”, and that “what the vulgar call chance is nothing but a secret and conceal’d cause”. This view plays a crucial role in Hume’s influential analysis of free will and moral responsibility. It functions also as a central presupposition in his discussion of miracles. However, Hume himself argued convincingly that the “maxim of causality”, according to which “whatever (...) begins to exist, must have a cause of existence” cannot be established a priori, by either intuition or demonstration. He concludes, then, that such “opinion must necessarily arise from observation and experience”. In the present article I analyse this latter statement, showing, first, what was Hume detailed proposal for funding the principle of causality on experience. Given the apparent weakness of this proposal, I then speculate on what kind of firmer empirical foundation could, instead, have been given, in Hume’s time, to the principle of causality, namely, the indirect support offered by Newtonian mechanics. Finally, I show how this theoretical link between experience and the principle, and also Hume’s straightforward, inductive argument, were undermined by the inception of quantum physics, at the beginning of the 20th century. (shrink)

Both in the Introduction to the Treatise of Human Nature and in the, Hume expressly declared that his goal was to contribute to the development of a “science of man” methodologically akin to the natural sciences, and capable of emulating their “accuracy” and explanatory success. He regarded these sciences as starting from careful observation of phenomena, and proceeding to the establish-ment of “principles” of increasing generality. Although rejecting as vain any hope of discovering “the ultimate principles” of any science, he (...) did not make clear what exactly he thought the principles actually involved in natural philosophy are. This article aims to shed some light on this issue through a survey and examination of the principles of Hume’s “science of man”, and of the most representative examples of principles of natural philosophy considered by Hume. (shrink)

This article aims to defend Locke against Quine’s charge, made in his famous “two dogmas” paper, that Locke’s theory of knowledge is badly flawed, not only for assuming the dogmas, but also for adopting an “in-tolerably restrictive” version of the dogma of reductionism. It is shown here that, in his analysis of the epistemological status of scientific laws, Locke has effectively transcended the narrow idea-empiricism which un-derlies this version of reductionism. First, in order to escape idealism, he introduced the notion (...) of “sensitive knowledge of the particular existence of finite beings without us,” broadening thus his initial definition of knowledge in terms of the “perception of the agreement or disagreement of ideas” — a definition compatible with Quine’s interpretation. Sec-ondly, after showing that we can have virtually no a priori knowledge of universal truths about substances, Locke extended the notion of “sensi-tive knowledge” to the particular propositions of “coexistence” in sub-stances, appealing to the notion of “probability” for treating their induc-tive generalizations and, in particular, the phenomenological laws of sci-ence. Finally, acknowledging the essential presence of hypothetical, non-phenomenological laws in science, he anticipated much of the contempo-rary views on their role and nature, including, remarkably, a mild ver-sion of the epistemological holism championed by Quine. (shrink)

In his influential criticism of scientific realism, Bas van Fraassen assumes that this doctrine is incompatible with empiricism, according to which the sole ultimate basis of knowledge is experience. This claim has been generally accepted in the contemporary literature in philosophy of science. Thus, the very distinction between scientific realism and empiricism is often forgotten, the term 'empiricism' being now widely used to designate a range of anti-realist positions, such as van Fraassen's "construct ive empiricism". In this paper it is (...) argued, first, that empiricism, in the traditional and proper sense of the word, is a thesis about the problem of the foundations of knowledge, and should therefore be clearly distinguished from anti-realism, which concerns the issue of the extension of knowledge. It is then conceded that the main arguments for scientific realism do indeed require that extra-empirical characteristics of scientific theories, such as simplicity and explanatory power, should be ascribed epistemic weight. Although this point lends support to van Fraassen's claim, it is indicated here that his constructive empiricism is threatened by the same kind of epistemological objections which he raises against his opponents. Like some other scientific anti-realists, van Fraassen avowedly embraces realism concerning ordinary material objects; but it is not clear that this form of anti-realism remains tenable when explanatory power, simplicity, etc. are regarded as merely pragmatic, non-epistemic virtues. (shrink)

The central aim of this article is to discuss Russell's analysis of the notion of cause. In his presidential address to the Aristotelian Society in 1912, Russell put forward several theses on causality in general, and specially on its role in science. He claimed that although vague references to causal laws are often found in the beginnings of science, "in the advanced sciences” the word 'cause' never occurs". Furthermore, Russell maintained that even in philosophy the word 'cause' is "so inextricably (...) bound up with misleading associations" that it would be desirable to promote its "complete extrusion from the philosophical vocabulary". These positions are rendered particular/y strong by Russell's explicit adhesion to the regular sequence view of causation, which he attributed to Hume. Essentially the same opinions were repeated in a series of lectures delivered in Boston two years later. After a systematic exposition of the main theses advanced by Russell on these two occasions, we trace their origin to his general conception of science. Then we examine the substantial changes that Russell's views on causality underwent several decades later. We remark that these changes seem to be intimately associated with the adoption of a new epistemological position concerning the nature of our knowledge of the external world, involving some clear elements of realism and naturalism. (shrink)