Finite verb to be omitted. For example, in the Latin sentence "cogito ergo sum" ("I think therefore I am") the finite verbs "cogito" and "sum" appear without an explicit subject – the subject is understood to be the first-person personal pronoun, and this information is marked by the way the verbs are inflected. In English, finite verbs lacking subjects are normal in imperative sentences: And also occur in some fragmentary utterances: The relatively poor system of inflectional morphology in English makes the central role that finite verbs play be often not so evident. In other languages, finite verbs are the locus of
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,