Cogito, ergo sum relying on clarity, distinctiveness, and self-evidence. Baruch Spinoza in ""Principia philosophiae cartesianae"" at its "Prolegomenon" identified "cogito ergo sum" the ""ego sum cogitans"" (I am a thinking being) as the thinking substance with his ontological interpretation. It can also be considered that "Cogito ergo sum" is needed before any living being can go further in life". Although the idea expressed in "cogito, ergo sum" is widely attributed to Descartes, he was not the first to mention it. Plato spoke about the "knowledge of knowledge" (Greek νόησις νοήσεως "nóesis noéseos") and Aristotle explains the idea in full length: But if life
Cogito, ergo sum of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Second, he does not say that his existence is necessary; he says that "if he thinks", then necessarily he exists (see the instantiation principle). Third, this proposition "I am, I exist" is held true not based on a deduction (as mentioned above) or on empirical induction but on the clarity and self-evidence of the proposition. Descartes does not use this first certainty, the "cogito", as a foundation upon which to build