Crathorn created unique theories in the philosophy of language and psychology, as well as in epistemology by focusing on the claims of skeptics.
Other areas of Crathorn's philosophy, which have not been extensively studied, show promise is revealing more about his life and his work.
Crathorn was born in Yorkshire and served as a Dominican friar, lecturing on a book from Peter the Lombard entitled Sentences.
His date of birth and death are unknown; the year in which he lectured is known only by an eclipse mentioned in his manuscripts which is known to have occurred in July 1330.
Crathorn asserts a somewhat Kantian view that we have no direct access to things in the external world and that we immediately perceive only their mental likenesses or representations (their species).
Like much philosophical discussion during his time in England, Crathorn considered the linguistic aspects of science.
Crathorn felt the entire system had to be revised; the human mind naturally knows only qualities, and one cannot be certain that even they exist without appealing to the principle that God could not deceive us.