 Crathorn thus had to emend Ockham’s theory of evident knowledge, because intuitive cognition is no more the guarantee of any certitude regarding the existence of extramental things. In addition, the cognition of the terms of a proposition — even a per se nota proposition — is not sufficient, according to Crathorn, to ensure the causal mechanism that leads to evidence and certitude. Indeed, as we shall see below, Crathorn refuses to treat the species or cognitions as linguistic elements of thought. All languages are conventional by nature. Therefore, it is possible to cognize some terms the signification of which remains unknown to the cognizing subject. As a result, although empirical knowledge of the things signified by the terms is usually needed, it is necessary to argue beyond simple and intuitive cognitions, via syllogisms and demonstrations, to consolidate one’s certitude that not only representations exist. Crathorn thus suggests that we substitute for the Ockhamist definition of evident cognition his own definition: evident cognition is a manifest, clear, and not obscure cognition (q. 1, p. 69–70: notitia evidens est notitia manifesta, clara et non obscura), be it simple or complex, intuitive or abstractive.