The Prince and the Cobbler: Why Personal Identity Is a Puzzle

Here is a puzzle that seems trivial until you think about it carefully: you are not made of the same matter you were ten years ago. The cells in your body have almost entirely been replaced. Your beliefs, values, and habits have changed significantly. Your earliest memories are blurry and possibly confabulated. In what sense are you the same person who was born, who started school, who had your first heartbreak?

Most of us would say: obviously I'm the same person, there is a continuous biological organism, a continuing stream of experience, a single set of personal relationships and responsibilities. But John Locke (1632–1704), in his Essay Concerning Human Understanding (Book II, Chapter 27, 1689), noticed that these answers don't obviously converge, and that pulling them apart reveals something philosophically surprising.

Locke distinguishes three concepts that are often conflated:

• Substance: the underlying matter or soul-stuff that constitutes an entity
• Man (or human organism): the biological animal, the living body with its characteristic organization
• Person: a thinking, conscious being capable of considering itself as itself, the same thinking thing, in different times and places, a being with memory connecting its past experiences to its present self

These three can come apart, and Locke uses a series of thought experiments to show how.

The famous Prince and the Cobbler: imagine that the soul of a prince, with all his princely memories, thoughts, feelings, and sense of identity, is transferred into the body of a cobbler, while the cobbler's soul departs. What do we have? - The substance (soul): the prince's

• The man (biological organism): the cobbler's body
• The person: the prince, because the consciousness, with all its memories and self-awareness, is the prince's

Locke concludes: the prince would wake up in the cobbler's body and rightly consider himself the prince. He would remember the queen as his mother. He would feel responsible for the prince's debts and contracts. The person, the locus of moral and legal responsibility, travels with the consciousness, not with the body.

Should the soul of a prince, carrying with it the consciousness of the prince's past life, enter and inform the body of a cobbler as soon as deserted by his own soul, everyone sees he would be the same person as the prince, accountable only for the prince's actions.

— John Locke, Essay Concerning Human Understanding, II.xxvii.15; quoted in Notre Dame philolibrary (2025)

This separability is what gives Locke's theory its distinctive shape. Personal identity, he argues, consists in psychological continuity, specifically, in memory connecting present consciousness to past experiences. You are the same person as the child who attended your first day of school if and only if you can, in principle, extend your present consciousness back to include the experiences of that child, to remember being her, or to remember someone who remembered someone who remembered her (a chain of memory-links).

The analogy that helps: think of personal identity as a chain, not a solid rod. A chain can flex, lose individual links, be repaired, but as long as the links overlap and connect, the chain is continuous. Your identity is like a chain of overlapping memory-connections: you don't need to remember being five years old directly, but if you remember being fifteen, and when you were fifteen you remembered being five, the chain connects. Break the chain completely, as in total amnesia, and Locke's view implies you have become a different person.