QuestionsWho am I, really?I am a thought that takes over the earlier ones: the thoughts themselves are the thinker
Who am I, really?My consciousness, my memory

I am a thought that takes over the earlier ones: the thoughts themselves are the thinker

The passing thought is the thinker

William James 1842 · 1910Religious experiences are psychological facts to be studied seriously, and belief can be a legitimate venture.
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What it claims

The passing thought is itself the thinker: the self is this succession of thoughts linked by likeness, continuity and inheritance, and psychology need not look further.

Why

Each thought recognises as its own the earlier ones that are close and continuous, and inherits them: no hidden self is needed.

The same idea through history
John Locke1694For Locke, the same person is the one who is conscious of having done their past acts. James keeps the idea of a consciousness that links, but describes it from the inside, as a feeling of "warmth" and continuity.David Hume1739Hume finds only perceptions in himself and denies any real connection between them. James takes up his observation, but refuses that there be only diversity: he also finds real likeness and continuity.
William James1890Chapter X of his Principles of Psychology, on the consciousness of self, offers a third path between the "substance" self and the "bundle" self: a succession of thoughts each of which inherits the previous one.
In short

"I am a thought that takes over the earlier ones: the thoughts themselves are the thinker" is an argument by William James (The Principles of Psychology, ch. X, 1890, 1890) on the question "Who am I, really?" (answer: my consciousness, my memory). Its claim: The passing thought is itself the thinker: the self is this succession of thoughts linked by likeness, continuity and inheritance, and psychology need not look further. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P5). AskPhilosophy presents 3 objections, 3 of them with a documented reply, and the original text behind each premise, checked word for word.

The Principles of Psychology, ch. X, 1890
Valid with an implicit premise

What makes me the same person as yesterday? Some answer: a soul, or a pure self, that does not change. Hume answers that there are only perceptions, with no real link. James refuses both. He first observes that each of our thoughts distinguishes those it recognises as its own from those it does not: some have "warmth and intimacy", like relatives greeting us from the past, the others seem cold and foreign. The sense of being the same is therefore a judgment like other judgments of sameness: it rests on likeness and continuity. James adds that each present thought takes the earlier ones as its own, as an heir takes over a title. No hidden thinker is needed: the passing thought is itself the thinker. He says so cautiously: this is the explanation psychology can give, the metaphysical question stays open.

P1Our thoughts do not fly about loose: each belongs to some thinker. A thought recognises among the others those that are its own: they have a "warmth and intimacy" that those it merely conceives, in a cold and foreign fashion, lack.
P2The sense of our personal identity is exactly like our other perceptions of sameness among phenomena. It is a conclusion grounded on resemblance in a fundamental respect, or on continuity between the phenomena compared. So it means no more than these grounds warrant: it is not an absolute metaphysical Unity.
P3Each present thought knows the previous one, finds it "warm" and greets it as its own. Each thought is thus born an owner and dies owned, transmitting to the next whatever it took for its Self: it inherits the title.
P4This description contains everything that can be verified in personal identity: one cannot imagine any observable fact that a transcendent Ego, were he there, would add to this succession of thoughts, each of which knows and adopts the previous ones.
P5 · implicit premiseWhen a description in terms of passing thoughts explains everything that can be verified, we need not add a thinker of another kind (soul, pure Ego): the passing thought is itself the thinker.
Therefore the passing thought is itself the thinker: the self is this succession of thoughts linked by likeness, continuity and inheritance, and psychology need not look further.

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 P5, the computer finds a case where the description by thoughts explains everything observable, yet a thinker of another kind exists all the same: for instance a soul that, by definition, would add nothing observable.
With P5 the argument is valid: the mark of "warmth" exists (P1), it grounds a judgment of likeness and continuity (P2), each thought inherits the previous one (P3), which explains everything verifiable (P4), and P5 draws from this that no other thinker is needed. Without P5 it is not: that the description by thoughts explains all we observe does not show that there is nothing else. This is the step contested by defenders of the soul or the pure Ego, and James knows it: he presents it as valid for psychology, not as a proof against metaphysics.
Analogy. A relay race. The first runner passes the baton to the second, who passes it to the third. No one is the same runner from start to finish; yet the team arrives with the same baton, and each knows what the earlier ones did. For James, the self is this baton handed on from thought to thought, with no hidden "super-runner" running the whole distance. His opponents answer that a baton is handed on only if someone, from start to finish, recognises it as the same.

Objections

3

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

Joseph Butler 1736 · attacks premise 2

Butler objects to Locke, and those who follow him, that this explanation is circular: consciousness of being the same person presupposes personal identity, so it cannot constitute it, any more than knowledge can constitute the truth it presupposes. A person has not existed only when they remember it. Butler also targets the idea of a "transient" personality that begins and ends continually.

James replies
William James 1890 · James's reply (the owner is the present thought)
James sees the circle: the beasts of a herd are not his because they bear his brand; they bear his brand because they are his. But he replies that his account has a real owner: the present thought, which looks on, remembers and judges, and which appropriates some of the past facts it surveys. The thought never appropriates itself. The unity so made is anchored in the present, not floating in the air of possibility.
The debate goes on (our summary) A defender of Butler would ask who establishes the inheritance: inheriting a title presupposes a testator and an heir who both exist, and an event of transmission. If each thought "dies" at every instant, nothing guarantees that the next truly inherits rather than merely resembling the previous one. Butler saw exactly this weakness in a personality that "lives and dies, begins and ends continually".
Immanuel Kant 1787 · attacks premise 4

For Kant, the "I think" must be able to accompany all my representations, otherwise something would be represented in me that could not be thought. The manifold of my representations thus necessarily relates to this "I think", in the subject in which it is found. A mere parade of thoughts does not account for this unity: a subject is needed to gather them.

James replies
William James 1890 · James's reply (transcendentalism teaches psychology nothing)
James replies that the transcendentalists themselves believe in Hume's "bundle": they merely tie it up with a special transcendental string, invented for that use alone. He reproaches the transcendentalists for forgetting the self's most important task: choosing among the things it ties together, appropriating some and leaving the rest. Our thought, an event in time, is, if it exists at all, the only thinker the facts require.
The debate goes on (our summary) James himself admits that the metaphysical question stays open: if one denied that we have direct knowledge of the thought as such, its existence would be reduced to "a postulate", and the question of who the knower is would become metaphysical; the soul, the transcendental Ego and his own solution would then be hypotheses of equal rank (end of the chapter). The debate thus turns on what counts as direct evidence of a thought.
David Hume 1739 · attacks premise 2

Hume holds that the identity we ascribe to the mind of man is only a fictitious one, of a like kind with that which we ascribe to vegetables and animal bodies. It comes from the imagination sliding easily from one perception to another that resembles it; it is not a real unity. The likeness and continuity James speaks of would then be only the product of this sliding.

James replies
William James 1890 · James's reply (the child with the bath)
James praises Hume's observation, then reproaches him for going to the opposite extreme from the substantialists: they say the self is pure unity, Hume says it is pure diversity. For James, the unity of the stream's parts is as "real" a connection as their diversity is a real separation: likeness and continuity are verifiable facts, not illusions. Hume demands a still more "real" link and seeks, says James, "the world behind the looking glass".
The debate goes on (our summary) Hume (died 1776) could not reply. A Humean would say that "likeness" and "continuity" are relations the mind notices, not a bond that makes a self. Parfit, later, will take a path close to both: there is no deeper fact than psychological continuity, and that is what matters.