Descarte said 'I think therefore I am', or in the orginal Latin, cogito ergo sum.

Is this analytic a priori?

The evidence for it being analytic, is that the first statement 'I think' includes a reference to the thinking 'I'. Assuming that this statement is a predicate (is it?) then the conclusion must follow, as the 'I' is already part of the predicate.

But is it a priori, that is independent of the world? It appears so as we've deduced the conclusion of the statement without reference to any world.

Is this correct?

  • "It appears as we've deduced the conclusion of the statement without reference to any world." But without reference to any experience ? I think not. But I think D's "feeling" about the cogito is that it is not an inference based on "deductive logic" (an argument) but instead a sort of "intuition". May 15, 2014 at 16:33
  • Sure - introspection is a kind of experience. I wasn't using formal logic in my discussion, but just ordinary language reasoning. May 15, 2014 at 17:05
  • It's worth noting that, historically, Kant came up with the notion of the analytic a priori and that he did so at least partially in response to Hume's refutations of Descartes. May 15, 2014 at 17:16
  • @Sunami: What was Hume refuting? May 15, 2014 at 17:18
  • He does not care about logic here. His is happy he can see the real truth himself. In the rest of the life he is trying to find truth using reason. He is happy he is not infinite self-doubting fractal.
    – Asphir Dom
    May 15, 2014 at 20:10

2 Answers 2


I'm sure it is a syntheic proposition because when he says 'I think', it is not a tautology. If you negate either word, it could still be true or false; 'I don't think' could still be true. I don't think that thinking is a predicate of 'I'.

Nevertheless, Descartes is trying to say that thinking IS a predicate of 'I' so 'I don't think'makes no sense because an 'I' (a human) has to think be an 'I'.


I would almost have to think that it is instead a priori. That which is a priori can be derived by reason alone. If you read Descartes' meditation on this topic, he uses only logic, but in the form of doubt. Since he uses only logic, the analytic cogito ergo sum can be only known through reason and, therefore, must be a priori

The other question to ask is why it's not a posteriori. A posteriori statements are unknown to reason alone. It prevents a clear answer that the analytic cannot fathomably be a posteriori because Descartes doubts anything but reason throughout the entirety of that meditation.

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