This paper offers an overview of consciousness and personal identity in eighteenth-century philosophy. Locke introduces the concept of persons as subjects of consciousness who also simultaneously recognize themselves as such subjects. Hume, however, argues that minds are nothing but bundles of perceptions, lacking intrinsic unity at a time or across time. Yet Hume thinks our emotional responses to one another mean that persons in everyday life are defined by their virtues, vices, bodily qualities, property, riches, and the like. Rousseau also (...) takes persons to be fundamentally determined by our socially-mediated emotional responses to one another, though unlike Hume or Locke, he has little interest in placing this account of persons alongside a larger discussion of the human mind and its operations. Developing this idea further, Kant argues that our moral commitments require that we must take ourselves to be free. The fundamental equality that Rousseau sought in the political order is, for Kant, a requirement that reason puts on all of us. (shrink)

In the Essay, Locke refers to the ordinary-sized natural things as ‘particular sorts of Substances’ (2.23), whereas the ‘three sorts of Substances’ (2.27) are more metaphysically laden sorts: God, finite spirits, and fundamental material particles. He posits the much-contested ‘substratum’ in each particular sort of substance but not any of the three sorts. It should also be noted that his list of the particular sorts includes ‘men’. In regard to this nobler sort, he refers to a further classification – viz., (...) ‘the Substance of spirit’ and ‘the Substance of the body’ – only in terms of their nominal essence. A naturalistic, nominalist approach is deeply entrenched in his account of the human-related sorts as well. In this chapter, I shall explore how Locke develops a theory of substance in the Essay that is less metaphysical, more naturalistic, and epistemically humbler than those of his rationalist contemporaries. (shrink)

In this paper, I will argue that Locke is a substance dualist in the general sense, in that he holds that there are, independent of our classificatory schema, two distinct kinds of substances: wholly material ones and wholly immaterial ones. On Locke’s view, the difference between the two lies in whether they are solid or not, thereby differentiating him from Descartes. My way of establishing Locke as a general substance dualist is to be as minimally committal as possible at the (...) outset, especially with respect to the classic debates on Locke’s positions in this domain, including those concerning substrata, real essences, and the like. Nonetheless, I show that minimal commitments about Locke’s primary/secondary quality distinction are sufficient to derive some substantive conclusions about his positions on these issues, as well as that he is a general substance dualist. (shrink)

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)

In the Monadology Leibniz has us imagine a thinking machine the size of a mill in order to show that matter can’t think. The argument is often thought to rely on the unity of consciousness and the notion of simplicity. Leibniz himself did not see matters this way. For him the argument relies on the view that the qualities of a substance must be intimately connected to its nature by being modifications, limitations of its nature. Leibniz thinks perception is not (...) a modification of matter because it is active and matter is passive. At the same time, there are traces in Leibniz of a different argument that relies on the notion of internal action, which may involve the notion of simplicity. Critics have sometimes charged that the Mill Argument is an argument from ignorance, but Leibniz was aware of this problem and made clear that he did not make that mistake. (shrink)

In this paper I criticize arguments by Pauline Phemister and Matthew Stuart that John Locke's position in his An Essay Concerning Human Understanding allows for natural kinds based on similarities among real essences. On my reading of Locke, not only are similarities among real essences irrelevant to species, but natural kind theories based on them are unintelligible.

Molyneux's Question, that is, “Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere... and the blind man made to see: Quaere, whether by his sight, before he touched them, he could now distinguish, and tell, which is the globe, which the cube”, was discussed by many theorists in the 17th and 18th centuries, and has recently been addressed by contemporary philosophers interested in the nature, and identity conditions, of (...) perceptual concepts. My main concern in this paper is to argue – against Evans, Campbell, and a number of other contemporary philosophers – that a test of the sort Molyneux envisioned, at least if carefully designed and administered, can indeed be a crucial experiment for the claim that we deploy the same perceptual concepts when identifying shapes by sight and by touch. I will explore some implications of this argument for a theory of recognitional concepts. And I’ll try to trace out some unhappy consequences of various alternative views. (shrink)

Locke’s argument for God’s immateriality in _Essay_ IV x is usually interpreted as involving a principle that in some way prohibits the causation of thought by matter. I reject these causal readings in favor of one that involves a principle which says a thinking being cannot be composed out of unthinking parts. This Composition Principle, as I call it, is crucial to understanding how Locke’s theistic argument can succeed in the face of his skepticism about the substance of matter and (...) the cause of thought, as well as his belief in the possibility of thinking matter. It also explains why Locke held the soul’s immateriality to be highly probable. (shrink)

In this encyclopedia entry I canvass the current interpretations of John Locke's concept of Real Essence and the role it plays in his philosophy.