Cartesian doubt is the basis for Descartes' statement, ""Cogito ergo sum"" ("I think, therefore I am"). Methodological skepticism is distinguished from philosophical skepticism in that methodological skepticism is an approach that subjects all knowledge claims to scrutiny with the goal of sorting out true from false claims, whereas philosophical skepticism is an approach that questions the possibility of certain knowledge. Cartesian doubt is methodological. Its purpose is to use doubt as a route to certain knowledge by finding those things which could not be doubted. The fallibility of sense data in particular is a subject of Cartesian doubt. There are several interpretations
Mr. Cogito whose presence is introduced by a poem entitled "Dusza Pana Cogito" (Mr. Cogito's Soul). It brings to our attention Mr Cogito's soul leading a life of its own. In contrast with the souls of the ancient world, it tends to leave him unexpectedly, wandering here and there, oblivious of the owner's well-being. The soul always returns, though, making it possible for Mr. Cogito to adore the world's beauty and diversity in the next poem – "Modlitwa Pana Cogito – podróżnika" ("A Prayer Of Mr. Cogito The Traveller"). This is followed by "Pan Cogito – powrót" ("Mr. Cogito – A Return"),