Non Cogito Ergo Non Sum

I'm sitting in a café when Descartes walks in and sits down at the table next to mine.
I pretend not to notice him, finish my coffee and call the waiter to pay. It's then I realise that I left my wallet at home.
I turn to Descartes and say, "Sorry, Monsieur, but do you think you could lend me 5 euros?"
"I think not…" he replies and suddenly disappears in a puff of smoke.