Locke, John (1632–1704)

DOI: 10.4324/9780415249126-DA054-1
Version: v1,  Published online: 1998
Retrieved December 10, 2018, from

8. Personal identity

The main aim of the chapter of the Essay entitled (‘Of Identity and Diversity’ (II.xxvii) is to explain how immortality is compatible with materialism. In order to maintain an agnostic neutrality on the question of the immateriality of the soul, Locke had, first, to rebut the Cartesian claim that self-awareness supplies a clear and distinct idea of a simple, continuously existing substance; and, second, to show that the metaphysical issue is irrelevant to ‘the great ends of morality and religion’ (Essay IV.iii.6). He argues that, although the moral agent is indeed the continuously existing, rational, self-aware subject of consciousness, the ‘person’, the identity of this subject over time is determined by the continuity of unitary consciousness itself, not the continuity of an immaterial soul. Locke can therefore accept the Resurrection and Last Judgment as tenets of his ‘reasonable’ Christianity, without commitment to dualism, on the supposition that the consciousness of the resurrected person is continuous, through memory, with that of the person who died. This conclusion avoids an objection to his concept of demonstrative ethics as a science of modes, that morality relates to ‘man’, a substance, not a mode. His response is that morality concerns, not ‘man’ as a biological species, but ‘man’ as rational, the ‘moral man’, indeed all rational beings. ‘Person’, as he puts it, is a ‘forensic term’.

Locke’s argument starts from the claim that questions of identity over time are always questions as to the continuous existence in space of something of a certain kind, and that difficulties may be avoided by ‘having precise notions of the things to which it is attributed’. The identity of non-substances is parasitic on that of substances: ‘All other things being but modes or relations ultimately terminated in substances’, their identity will be determined ‘by the same way’ (Essay II.xxvii.2). Locke holds that events and processes (‘actions’) are not strictly identical from moment to moment, each part of what we consider one process being distinct from every other part. Substances, however, genuinely continue to exist from moment to moment. The identity of ‘simple substances’ – material atoms and the presumed simple ‘intelligences’ – is straightforward. Each excludes others of the same kind out of its place by its very existence – a principle definitive of identity. But difficulties arise with compound substances. Strictly, a body composed of many atoms is the same just as long as the same atoms compose it – yet ‘an oak, growing from a plant to a great tree, and then lopped, is still the same oak’. Locke’s explanation is that ‘in these two cases of a mass of matter, and a living body, identity is not applied to the same thing’ (Essay II.xxvii.3). Although he does not clearly distinguish the two views, he seems to hold individuation, rather than the identity-relation, to be kind-relative. A plant or animal is not just ‘a cohesion of particles anyhow united’, but such an organization of parts as enables the continuation of its characteristic life, for example, as an oak. In fact the species of the living thing is irrelevant to Locke’s theory (fortunately, given his view that the definition of ‘oak’ will differ from speaker to speaker). The essential claim is that life is a principle of unity and continuity distinct from simple cohesion, thus allowing a living thing and the mass of matter that momentarily composes it so to differ in kind as to be capable of occupying the same place at the same time.

Locke defines person as ‘a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing at different times and places’ (Essay II.xxvii.9). His thesis is that, just as life constitutes a distinct individuative principle of unity and continuity, so does reflexive consciousness. He argues for the logical independence of the continuity of consciousness from both the continuity of substance (whether supposed material or immaterial, simple or complex) and the continuity of animal life by a series of imagined cases: for example, for someone now to possess Socrates’ soul would not make him the same person as Socrates, unless he remembered Socrates’ actions as his own; whereas if souls are the seat of consciousness, and the soul of a prince could migrate to the body of a cobbler, ‘everyone sees he would be the same person with the prince, accountable only for the prince’s actions. But who would say it was the same man?’ (Essay II.xxvii.15). Locke viewed such cases, not necessarily as real possibilities, but as compatible with our partial understanding of things, our ideas: ‘for such as is the idea belonging to that name [namely ‘person’, ‘man’ or ‘substance’], such must be the identity’. Yet in the crucial case of the Resurrection, we are left wondering how continuous existence through time – not to speak of space – is achieved simply by a fit between present consciousness and past experience and actions. Indeed, as Berkeley and Reid argued, memory-links seem both too little and too much for the continuity of a substantial thing. Yet, despite these and other difficulties for Locke’s theory, it set the agenda for subsequent discussion and versions of it still have adherents (see Personal identity).

Citing this article:
Ayers, Michael. Personal identity. Locke, John (1632–1704), 1998, doi:10.4324/9780415249126-DA054-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
Copyright © 1998-2018 Routledge.

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