Full Idea
Descartes claimed to know that he existed before he knew what he was - before he grasped his own essence. This is either disingenuous or intended non-literally, if it is not to be dismissed as incomprehensible.
Gist of Idea
Descartes' claim to know his existence before his essence is misleading or absurd
Source
report of René Descartes (Meditations [1641], 2) by E.J. Lowe - Two Notions of Being: Entity and Essence 2 n32
Book Reference
'Being: Developments in Contemporary Metaphysics', ed/tr. Le Poidevin,R [CUP 2008], p.40
A Reaction
If something comes at you from the mist, you can know that it exists before you know what it is. How could you understand the essence of something if you hadn't first encountered its existence? Lowe has it the wrong way round.