Possible Origins of the Idea of the Soul: Dreams, Trances, and Ghosts
Is death anything else than the separation of the soul from the body? Do we believe that death is this, namely, that the body comes to be separated by itself apart from the soul, and the soul comes to be separated by itself apart from the body? This is exactly what death is and it shows the relationship between the soul and the body. When death has occurred, the soul disdains from the body and flees from it and seeks to be by itself. The essence of soul is the attribute that makes a soul what is it, which is to think. What is a dream? Descartes must explore all doubts involving his internal sense if he wants to use it as his foundation for knowledge. He brings up the possibility that perhaps at this point, right now, he is dreaming. A person who is dreaming may have difficulty differentiating between the dream and reality. This dream hypothesis would invalidate the beliefs that are based on internal sense; for if you are dreaming then what you believe to be your awareness of self is truly false. Dreams have little rhyme or reason; while life experience is orderly and controlled.
What is the Soul? According to Plato: The Phaedo
As regards the soul, although many have considered that it is not easy to know its nature, and some have even dared to say that human reasons have convinced us that it would perish with the body. In the first place, Descartes thought that he possessed a countenance, hands, arms, and all the fabric of members that appears in a corpse, and which he called by the name of body. It further occurred to him that he was nourished, that he walked, perceived, and thought, and all those actions he referred to the soul; but what the soul itself was, he either did not stay to consider, or, if he did, he imagined that it was something extremely rare and subtle, like wind, or flame, or ether, spread through my grosser parts. Let us pass, then, to...