First principle foundationalist system of philosophy. He used the "method of doubt", now called Cartesian doubt, to systematically doubt everything he could possibly doubt, until he was left with what he saw as purely indubitable truths. Using these self-evident propositions as his axioms, or foundations, he went on to deduce his entire body of knowledge from them. The foundations are also called "a priori" truths. His most famous proposition is "Je pense, donc je suis." ("I think, therefore I am", or "Cogito ergo sum") Descartes describes the concept of a first principle in the following excerpt from the preface to the "Principles
Mr. Cogito which unequivocally identifies the character with the poet for the very first time in the oeuvre. It mentions his return to his homeland, and the other poems in the collection treat about various aspects of Mr. Cogito's being – imagination ("Mr. Cogito and the Imagination"), longevity ("Mr. Cogito and Longevity"), virtue ("Mr. Cogito on Virtue"), eschatological concepts ("Mr. Cogito's Eschatological Premonitions"), bloodshed ("Mr. Cogito Thinks about Blood"), a contact with Maria Rasputin ("Mr. Cogito and Maria Rasputin – an Attempt at Contact"), the need for precision ("Mr. Cogito on the Need for Precision), the notes from a house of the