Ergo Proxy inside of themselves: the idea that there are two personalities inside a person and noted that René Descartes' phrase ""cogito, ergo sum"" was the inspiration for it. Satō stated that they originally did not want to explicitly express the concepts of Gnosticism in the anime. However, their personal beliefs ended up reflecting the ideas of Gnosticism and realized how well these terms fit and decided to use them. At first they intended to have Vincent as the leading protagonist and Re-l as a supporting character; however, as they fleshed out her character, she became a much stronger character and began
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"),