Rationalism senses. For instance, his famous dictum, "cogito ergo sum" or "I think, therefore I am", is a conclusion reached "a priori" i.e., prior to any kind of experience on the matter. The simple meaning is that doubting one's existence, in and of itself, proves that an "I" exists to do the thinking. In other words, doubting one's own doubting is absurd. This was, for Descartes, an irrefutable principle upon which to ground all forms of other knowledge. Descartes posited a metaphysical dualism, distinguishing between the substances of the human body (""res extensa"") and the mind or soul (""res cogitans""). This
Mr. Cogito Cogito and Pure Thought"), "Pan Cogito czyta gazetę" ("Mr. Cogito Reads A Newspaper"), "Pan Cogito a ruch myśli" (" Mr. Cogito and the Motion of Thought"), "Domy przedmieścia" ("Houses On The Outskirts Of The City"), "Alienacje Pana Cogito" ("Mr. Cogito's Alienations"), "Pan Cogito obserwuje zmarłego przyjaciela" ("Mr. Cogito Watches a Deceased Friend"), "Późnojesienny wiersz Pana Cogito przeznaczony dla kobiecych pism" ("Mr. Cogito's Late Autumn Poem For Women's Magazines"), "Pan Cogito rozważa różnice między głosem ludzkim a głosem przyrody" ("Mr. Cogito Considers the Difference Between the Human Voice And The Voice of Nature"), "Pan Cogito biada nad małością snów" (Mr. Cogito