No, I meant N3 sleep. You are still conscious in that state, there's just nothing to be aware of, because, as you say, there's no thinking and thus no dreams. As for Descartes, I'm not exactly familiar with his work sans the famous quote and the implications his body-mind dualism had on developments that followed. I could stomach the quote to an extent, but I suppose it's tied closely to the rest of his ideas and body-mind dualism is simply quite off--you cannot separate hardware from software. Or better said you can, but all such distinctions are more or less artificial and don't correspond with what can be observed. Thus, I consider Descartes' realizations as incomplete.