I am thing that thinks: that is, a things that doubts,affirms, denies, understands a few things, is ignorant of many things, is willing, is unwilling, and also which imagines and has sensory perceptions.
Rene DescartesLet whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.
Rene Descartes