Being and Nothingness it has been suggested that it usually went unread by them. Sartre's reflections on slime ("le visqueux") have been described as celebrated. Sartre's existentialism shares its philosophical starting point with René Descartes: The first thing we can be aware of is our existence, even when doubting everything else (Cogito ergo sum). In "Nausea", the main character's feeling of dizziness towards his own existence is induced by things, not thinking. This dizziness occurs "in the face of one's freedom and responsibility for giving a meaning to reality". As an important break with Descartes, Sartre rejects the "primacy of knowledge", as summed
Cogito, ergo sum for thought". In other words, "the only claim that is indubitable here is the agent-independent claim that there is cognitive activity present". The objection, as presented by Georg Lichtenberg, is that rather than supposing an entity that is thinking, Descartes should have said: "thinking is occurring." That is, whatever the force of the "cogito", Descartes draws too much from it; the existence of a thinking thing, the reference of the "I," is more than the "cogito" can justify. Friedrich Nietzsche criticized the phrase in that it presupposes that there is an "I", that there is such an activity as "thinking",