Descartes explains how he made a mention of the two questions, the existence of God, and the soul, in his "Discourse on Method". Following this, he received objections, and two of them he considers are of importance. The first is how he concludes that the essence of the soul is a thing that thinks, excluding all other nature. To this he says that he has a clear perception that he is a thinking thing, and has no other clear perception, and from this he concludes that there is nothing else in the essence of the self.