Cogito: From Descartes to Sartre

Cogito, as the first principle of Descartes’ metaphysical system, initiated the modern philosophy of consciousness, becoming both the source and subject of modern Western philosophical discourse. The philosophies of Maine de Biran, Kant, Husserl, Heidegger, Sartre, Merleau-Ponty, and others developed by answering the following questions? Is consciousness substantial or not? Does consciousness require the guarantee of a transcendental subject? Is Cogito epistemological or ontological? Am I a being-for-myself or a being-for-others? Outlining the developmental history of the idea of Cogito from Descartes to Sartre is important for totally comprehending the evolution and development of Western philosophy.