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
Cogito, ergo sum familiar form of the phrase in his 1641 "Meditations on First Philosophy". The earliest written record of the phrase in Latin is in his 1644 "Principles of Philosophy", where, in a margin note (see below), he provides a clear explanation of his intent: "[W]e cannot doubt of our existence while we doubt". Fuller forms of the phrase are attributable to other authors. The phrase first appeared (in French) in Descartes's 1637 "Discourse on the Method" in the first paragraph of its fourth part: In 1641, Descartes published (in Latin) "Meditations on first philosophy" in which he referred to the proposition,