Cogito ergo sum

Cogito ergo sum was a philosophical statement, suggesting that all a person truly knows is that they exist. (AUDIO: Minuet in Hell, Zagreus)

Translated from Latin, it means "I think therefore I am". (AUDIO: Zagreus)

Gideon Crane used it to mock the Eighth Doctor while the latter was in a state of amnesia. (AUDIO: Minuet in Hell)