This chapter brings some much-needed conceptual clarity to the debate about Locke’s scientific methodology. Instead of having to choose between the method of hypothesis and that of natural history (as most interpreters have thought), he would resist prescribing a single method for natural sciences in general. Following Francis Bacon and Robert Boyle, Locke separates medicine and natural philosophy (physics), so that they call for completely different methods. While a natural philosopher relies on “speculative” (causal-theoretical) hypotheses together with natural-history making to (...) explicate phenomena, a medical practitioner must prioritize collecting data about what remedies tend to cure what diseases over hypothesizing about the causes of the latter. (shrink)

This paper explores two related issues concerning Locke’s account of epistemic justification for empirical knowledge. One issue concerns the degree of justification needed for empirical knowledge. Commentators almost universally take Locke to hold a fallibilist account of justification, whereas I argue that Locke accepts infallibilism. A second issue concerns the nature of justification. Many (though not all) commentators take Locke to have a thoroughly internalist conception of justification for empirical knowledge, whereas I argue that he has a (partly) externalist conception (...) of justification: it is the fact that sensation is caused by an external object that justifies our belief in the corresponding object. So, while most commentators take Locke to be a fallibilist with an internalist conception of justification for empirical knowledge, I argue he is actually an infallibilist with an externalist conception of justification. (shrink)

Locke seems to hold that we have knowledge of the existence of external objects through sensation. Two problems face Locke's account. The first problem concerns the logical form of knowledge of real existence. Locke defines knowledge as the perception of the agreement or disagreement between ideas. However, perceiving agreements between ideas seems to yield knowledge only of analytic truths, not propositions about existence. The second problem concerns the epistemic status of sensitive knowledge: How could the senses yield certain knowledge? This (...) essay argues that the key to solving both problems is Locke's claim that simple ideas are all real, adequate, and true. This explains why, on Locke's view, we have certain knowledge through the senses. It also explains how sensitive knowledge can consist in perceiving an agreement between ideas: perceived agreements among simple ideas of sensation are guaranteed to track relations that obtain among really existing things. (shrink)

There are at least three deep and yet creative tensions in John Locke's writings on the knowledge of the natural world. An exposition of these tensions provides the framework for this chapter. The chapter provides an account of the development of Locke's views from his early medical essays of the late 1660s to his last published writings on natural philosophy. The central locus for Locke's "philosophy of science" will be the Essay. Chymical medicine provided the main field in which Locke (...) was regularly involved in experimentation. Locke believed that geometry and arithmetic presented paradigm examples of the sort of demonstrative reasoning that would be involved in a science of nature, that is, a demonstrative natural philosophy. An important consequence of Locke's ideal of a corpuscular metric is an ongoing concern with metrology. By the early 1690s, Locke modified his views on natural philosophy in the light of the Newtonian achievement. (shrink)

Locke famously claimed that morality was capable of demonstration. But he also refused to provide a system of demonstrative morality. This paper addresses the mismatch between Locke’s stated views and his actual philosophical practice. While Locke’s claims about demonstrative morality have received a lot of attention it is rare to see them discussed in the context of his general theory of demonstration and his specific discussions of particular demonstrations. This paper explores Locke’s general remarks about demonstration as well as his (...) claims about demonstration in natural philosophy, mathematics, and morality. Careful attention to these detailed discussions motivates a reevaluation of Locke’s views on demonstrative knowledge of morality. Specifically, while Locke did believe that some demonstrative moral knowledge might be in-principle available to us he also believed that facts about the difficulty of demonstration meant that this knowledge would in-practice be largely unattainable. (shrink)

Locke’s claim that the primary signification of (most) words is an idea, or complex of ideas, has received different interpretations. I support the majority view that Locke’s notion of primary signification can be construed in terms of linguistic meaning. But this reading has been seen as making Locke’s account vulnerable to various criticisms, of which I consider two. First, it appears to make the account vulnerable to the charge that an idea cannot play the role that a word meaning should (...) play. I argue that the role Locke actually gives to signified ideas is not susceptible to this criticism. Second, it appears to make Locke guilty of at least some degree of semantic idealism. I argue that Locke is not guilty of this and that he makes a proper distinction between the non-referential relation that holds between a word and its primary signification and the referential relation that holds between a word and things the word is used to speak about. (shrink)

In 1792 Dugald Stewart published Elements of the philosophy of the human mind. In its section on abstraction he declared himself to be a nominalist. Although a few scholars have made brief reference to this position, no sustained attention has been given to the central role that it played within Stewart’s early philosophy of mind. It is therefore the purpose of this essay to unpack Stewart’s nominalism and the intellectual context that fostered it. In the first three sections I aver (...) that his nominalism emanated from his belief that objects of the mind—qualities, ideas and words—were signs that bore no necessary relation to the external objects that they were meant to represent. More specifically, it was these signs that were arranged into systems of thought by the ‘operations of the mind’. The next three sections suggest that his treatment of words as signs most probably originated in his views on language and medicine and that his nominalistic philosophy of mind could also be extended to systems that sought to classify the natural world. I conclude by suggesting several avenues of enquiry that could be pursued by future scholars interested in excavating Stewart’s thought. (shrink)

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)

John Locke famously claimed that our idea of substance is but a confused idea of “something we know not what.” However, he also thought that the idea of substance is a fundamental part of our ideas of ourselves and the objects surrounding us—of objects we do know. Interpreting this apparently ambivalent stance has long been a major challenge for Locke scholarship. In this article, I argue that the leading interpretations of Locke's conception of substance have failed to resolve this tension (...) because they have misconstrued the source of Locke's skepticism about our knowledge of what substance is. This skepticism, I argue, issues from an observation about the signification of the term “substance”: Locke maintained that the philosophical usage of the term is irremediably equivocal. This reading allows us to acknowledge that Locke could consistently hold that ordinary objects, such as persons, horses, or trees, are paradigmatic examples of substances. It also points to a better appreciation of how Locke's discussion of substance relates to the scholastic conceptions of substance he tried to overcome. (shrink)