Single Idea 3623

[catalogued under 11. Knowledge Aims / B. Certain Knowledge / 5. Cogito Critique]

Full Idea

In order to be certain that you are thinking you must know what thought or thinking is, and what your existence is; but since you do not yet know what these things are, how can you know that you are thinking or that you exist?

Gist of Idea

The Cogito only works if you already understand what thought and existence are

Source

comment on René Descartes (Meditations [1641], §2.26) by Marin Mersenne - Objections to 'Meditations' (Sixth) 413

Book Reference

Descartes,René: 'Meditations on First Philosophy etc.', ed/tr. Cottingham,John [CUP 1986], p.69