Source
Locke (1694), “Of Identity and Diversity”, An Essay Concerning Human Understanding II.xxvii, LIT-464, read in the sixth-edition text in NOTE-385. The objections and repairs: Olson (2002; rev. 2023), the SEP entry “Personal Identity”, LIT-454, read in NOTE-374; and Parfit (1971), LIT-447, read in NOTE-378.
What was actually shown
Identity is relative to the kind (Locke §§3–8). A mass of atoms is no longer the same mass if one atom is added or taken away; an oak, a horse and a man are the same while they share “the same continued life” in “constantly fleeting particles of matter” (§6). “It being one thing to be the same substance, another the same man, and a third the same person” (§7).
The criterion (§9). A person is “a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places”. Its identity reaches “as far as this consciousness can be extended backwards to any past action or thought”.
Man and person come apart (§§10–15, 23). Different substances joined by one consciousness make one person (§10). The prince’s soul, “carrying with it the consciousness of the prince’s past life”, in the cobbler’s body is “the same person with the prince” and “the same cobbler to every one besides himself” (§15). Two “incommunicable consciousnesses” acting one body by turns are two persons (§23). “Person” is “a forensic term, appropriating actions and their merit” (§26).
What Locke leaves open. “The same consciousness” is never defined. Locke grants it is “not the same individual act” (§13), and his gloss, “a present representation of a past action”, would include false memory, which he sees and refers to “the goodness of God” (§13). He does not consider that consciousness reaching from A to B and from B to C need not reach from A to C (NOTE-385, Limitations).
The repairs. The survey sets out three objections to a memory criterion and their answers (LIT-454 §4). It fails transitivity (the student, the lawyer and the old woman), answered by chains of overlapping connections. It is circular, since genuine memory presupposes identity, answered by quasi-memory: Parfit’s q-memory is memory without the condition that the experience was one’s own, which “vindicates the ‘memory criterion’ of personal identity against the charge of circularity” (LIT-447, p. 16). It fails dreamless sleep, answered by causal dependence (Shoemaker): beliefs “have caused themselves to continue existing”. Fission then forces either multiple occupancy or a non-branching clause (§5), which Parfit supplies: X and Y are the same person if psychologically continuous and no contemporary person is continuous with either (LIT-447, p. 13), as a sufficient condition only. In the survey, psychological views are the majority position.
What could have come out otherwise. The objections could have shown that no psychological relation can be transitive, non-circular and robust through gaps. Each has an answer the survey reports, and the open case that remains is brain-state transfer.
What this does not say
- That Locke made identity a matter of memory alone. Velleman reads him so (LIT-292, NOTE-268). The chapter’s word is “consciousness”, of “thoughts and actions” and of concern for one’s happiness (§§17, 26), though every case it uses is one of remembering.
- That Locke answered the objections. He did not anticipate circularity or intransitivity; the repairs are two and three centuries later.
- What we are. A persistence criterion does not say what kind of thing persists by it. Olson’s too-many-thinkers objection is that if we persist psychologically we are not organisms, yet the organism thinks too, so there are two thinkers in your chair and you cannot know which you are (LIT-454 §6). The survey reports the replies and calls them “hard to defend”. It is written by the leading animalist, and NOTE-374 calls it a survey with a side.
- Whether brain-state transfer counts. Left open (Shoemaker yes, Unger no), and it is the case on which copying and re-instantiation turn.
- That identity is what matters. That is a further question (THEORY-447), and the non-branching clause is where Parfit concludes it is not.
- Where the self’s boundary is. Locke’s little finger, part of me while consciousness reaches it (§§11, 17), is a claim about the self’s extent, asserted “as every one who reflects will perceive”.
Connections
- QUESTION-043 asks what coherence measure is conserved along a person’s trajectory when the person persists. This account constrains the answer: what persists is not any content, since memories fail transitivity and are lost, but an overlapping chain of causal dependence among psychological states. That is a relation along the trajectory, not a conserved quantity, and it can branch, which is why a clause against branching has to be added.
- Hume (THEORY-681) turns Locke’s analogy between the identity of plants and animals and that of persons against him: both are fictions. His Appendix says “most philosophers seem inclin’d to think, that personal identity arises from consciousness”, which is this chapter’s thesis.
- Williams (THEORY-531). The prince and the cobbler is the third-person telling, with its verdict; the first-person series reverses it.
- The question map (THEORY-417). This is an answer to the persistence question, not to the characterization question that narrative accounts take up.
- Floridi (THEORY-650) credits Locke with separating kinds of sameness question. Locke’s own diagnosis, that the difficulty “rather rises from the names ill-used” (§28), is half of Floridi’s deflation.