QuestionsWho am I, really?King of China with no memories: it would no longer be me
Who am I, really?My consciousness, my memory

King of China with no memories: it would no longer be me

Leibniz's king of China

Gottfried Wilhelm Leibniz 1646 · 1716We live in the best of all possible worlds.
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What it claims

Being the same person, in the sense that matters, requires memory or consciousness of the self: without it, the same soul would no longer be "me" for morality.

Why

Becoming king of China while forgetting all you were would amount to vanishing: without memory, surviving has nothing to wish for.

The same idea through history
John Locke1694A few years later, Locke makes consciousness of one's past actions the criterion of personal identity, without resting it on a soul. Leibniz will answer him, in the New Essays, that it is not enough without a real identity behind it.
In short

"King of China with no memories: it would no longer be me" is an argument by Gottfried Wilhelm Leibniz (Discourse on Metaphysics, § 34 (1686)) on the question "Who am I, really?" (answer: my consciousness, my memory). Its claim: Being the same person, in the sense that matters, requires memory or consciousness of the self: without it, the same soul would no longer be "me" for morality. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P3). AskPhilosophy presents 3 objections, 2 of them with a documented reply, and the original text behind each premise, checked word for word.

Discourse on Metaphysics, § 34 (1686)
Valid with an implicit premise

Leibniz believes the soul is a substance that does not perish. But he asks whether that is enough for us to truly survive. His example: a man could become king of China, on condition of forgetting everything he has been. What would he gain? As far as anything can be observed, it would be as if he had been annihilated and another king created in his place. The immortality that matters, says Leibniz, is one where I remember having been myself, and it is this memory, or consciousness of the self, that allows me to be rewarded or punished. Why is this argument placed in the "consciousness" camp when Leibniz keeps the soul? Because he separates two things: "real" identity, that of the same substance, which he maintains, and "moral" or personal identity, the only one that matters for responsibility and for hoping to survive. For the second, he answers as Locke does: it is self-consciousness. He adds, however, that the testimony of others can fill a gap in memory.

P1For survival to be worth wishing for, one must remember what one has been. A mere subsistence of the substance, which belongs to all substances, is not what is asked for in morals and religion: becoming king of China while forgetting everything would amount, as far as anything can be observed, to being annihilated.
P2To be open to reward or punishment, one must remember, or know, the self that acted: it is memory that makes one open to punishment or reward.
P3 · implicit premiseBeing the same person, in the sense that matters, means that my survival can matter to me or that my acts can be imputed to me. The mere continuity of the substance does not settle either question.
Therefore being the same person, in the sense that matters, requires memory or consciousness of the self: without it, the same soul would no longer be "me" for morality.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P3, the computer finds a case where survival cannot matter without memory, where imputation requires memory, and where one is nonetheless the same person without memory: nothing yet connects "being the same person" to those two questions.
The argument is valid with the hidden premise P3. If being the same person means that my survival can matter to me or that my acts can be imputed to me (P3), and both require memory (P1, P2), then being the same person requires memory. The objections target the conclusion: they say memory already presupposes identity (Butler), that it falls short (Reid), or that identity is not what matters (Parfit).
Analogy. An actor who loses all memory of his plays remains the same human being, but the company no longer has reason to pay him a lead's salary or blame him for lateness. Likewise, says Leibniz, without memory of oneself, the same soul could neither hope nor answer for anything.

Objections

3

Each objection is a conversation: click to see who replies and where the debate stands.

Joseph Butler 1736 · attacks the conclusion

Consciousness of personal identity presupposes personal identity, so it cannot constitute it. For my memory of an action to be true, it must already be I who did it. Saying that memory makes identity is going in a circle.

a defender replies
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Leibniz (New Essays, written before Butler) defender of the argument · 1704 · What Leibniz already answers Locke
Leibniz does not make identity depend on memory. The self is the real identity of the substance; the appearance of the self, when true, adds personal identity to it. Memory shows identity more than it makes it. But without memory or testimony, this real identity does not, in his view, suffice to ground responsibility.
Where the debate stands (our summary)Our summary: Butler targets Locke, but the objection also touches any memory-only criterion. Leibniz's answer is to keep two levels: a real identity (the substance) and a moral identity (consciousness). Whether this split is enough remains debated.
Thomas Reid (the brave officer) 1785 · attacks the conclusion

A boy is flogged, becomes an officer who remembers it, then a general who remembers the officer but no longer the boy. If memory makes identity, the general is the officer, the officer is the boy, and yet the general is not the boy: that is contradictory.

a defender replies
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Leibniz (New Essays, written before Reid) defender of the argument · 1704 · A middle link, and the testimony of others
For Leibniz, it is enough that there is a middle link of consciousness between neighbouring states, even somewhat distant ones, with a forgotten interval in the middle. And if memory has a gap, the testimony of others can fill the void of my recollection: forgotten acts can be imputed to me.
Where the debate stands (our summary)Our summary: Reid's example hits Locke, who ties identity to direct memory alone. Leibniz has already foreseen forgetting: he accepts chains of overlapping memories and testimony. It remains to ask whether one can still speak of "memory" when one learns one's life from others.
Derek Parfit 1984 · attacks premise 3

What matters when I think about my survival is not strict identity, nor memory alone, but psychological continuity and connectedness (memories, intentions, beliefs, character) when they have an appropriate cause. In borderline cases, the question "is it still me?" may have no answer, without changing what matters.

no reply
see the argument
No reply possible: objection raised in 1984, after the author's death (1716).
The debate goes on (our summary) Our summary: Parfit takes up the idea of Leibniz and Locke that psychological life matters more than the body, but he widens memory to other links and refuses to make it a criterion of strict identity. Leibniz, who keeps a real soul behind it, would probably not have accepted that there is no deep fact about the self.
Where the debate stands (our summary)Our summary: a deep disagreement over the existence of a real "self" behind psychological states. For Leibniz there is a substance; for Parfit there are only the links. No consensus.