- Created synthesis of Aristotle and Christianity - changed direction of Christian theology; His theology is still the cornerstone of Catholicism.
- Separated faith from reason
- allowed two ways of seeking truth
- destroyed stranglehold of religion on intellectual pursuits
- made the study of nature respectable
- Wrote extensively about human psychology and the nature of the soul, much of it derived from Aristotle
- opened the door for the development of science, but the growth of scholasticism would also be a problem for it later on.