Descartes' Cogito: Philosophical Critiques of the Self

Philosophical Critiques of Descartes' "Cogito Ergo Sum"

Huet's Challenge to Cartesian Evidence

A critique, often attributed to Pierre Daniel Huet, questions the Cartesian "Cogito ergo sum." It posits that we cannot accept the existence of reason as self-evident if its establishment as the rule of evidence could have been manipulated by an evil genius.

Descartes' Answer: Descartes counters that reason is an intuitive truth that reveals itself; it does not merely validate a rule of evidence established on a provisional basis. On the contrary, finding that the existence of reason is an irrefutable truth is, in fact, legitimized by the rule of evidence (though, Descartes concedes, ultimately legitimized only by God).

Hume's Empiricist Critique of the Thinking Substance

David Hume criticizes the possibility of a "thinking substance" and the idea of the "self" as such a substance. Hume points out that when we introspect, we observe not a simple, permanent self, but a continuous cluster of perceptions succeeding one another. This directly challenges the Cartesian view of the self as a primary thinking entity (res cogitans).

When Descartes asserts, "I think, therefore I am," he believes this knowledge also ensures that he is a thinking substance. His thesis doesn't just conclude that thought exists, but that a substance that thinks exists. Rationalism, building upon this foundational truth, also regards the self as a substance—an entity characterized by simplicity and permanence, often interpreted in spiritual terms (i.e., as a soul).

Hume rejects this. Applying an empiricist approach, he notes that if we adhere strictly to what we observe in our own minds, we find no permanent impressions, only a continuous succession of ideas. The consciousness of identity we attribute to ourselves stems not from any substantial character of our self, but from memory and the succession of these impressions; we mistake this succession for identity. For Hume, the self is not simply this collection of impressions but rather a bundle or collection of different perceptions, succeeding each other with great rapidity.

Nietzsche's Critique of the Cartesian "Ego"

Friedrich Nietzsche views the Cartesian "ego" as a prime example of an ontological illusion fostered by language. He argues that the most pernicious illusion promoted by language is the quintessential ontological illusion of identity: the self.

Nietzsche states, "A thought comes when 'it' wants, and not when 'I' want." Therefore, it is a distortion of actual reality to assert that the subject "I" is the condition of the predicate "think." Rather, "It thinks." To claim that this "it" is precisely that famous old "self" is, speaking softly, nothing more than a hypothesis, an assertion, and, above all, not an immediate certainty. Ultimately, to say "I think" is already an interpretation of the process, not a part of the process itself.

Bertrand Russell's Note on Descartes' Doubt

Bertrand Russell, in his Principles of Philosophy (likely a reference to discussions in works like The Problems of Philosophy), notes Descartes' progression: to doubt is to exist. Since doubt is a form of thought, it follows that thought exists.