Belonging to the analytic and evidentialist schools of thought, Flew was most notable for his work related to the philosophy of religion.During the course of his career he taught at the universities of Oxford, Aberdeen, Keele and Reading, and at York University in Toronto.After a period with the Inter-Services Topographical Department in Oxford, he was posted to Bletchley Park in June 1944.Flew was a graduate student of Gilbert Ryle, prominent in ordinary language philosophy.
He also answered in the affirmative to Habermas's question, "So of the major theistic arguments, such as the cosmological, teleological, moral, and ontological, the only really impressive ones that you take to be decisive are the scientific forms of teleology? He supported the idea of an Aristotelian God with "the characteristics of power and also intelligence", stating that the evidence for it was stronger than ever before.
Upon his retirement, Flew took up a half-time post for a few years at York University, Toronto.
Politically Flew was a libertarian-leaning conservative and wrote articles for The Journal of Libertarian Studies.
Harvey Ward, on behalf of the Institute, "applauding Alfredo Cristiani's statesmanship" and calling for his government's success in defeating the Cuban and Nicaraguan-backed communist FMLN terrorists in El Salvador. Although he found Lewis to be "an eminently reasonable man" and "by far the most powerful of Christian apologists for the sixty or more years following his founding of that club", he was not persuaded by Lewis's argument from morality as found in Mere Christianity.
While an undergraduate, Flew attended the weekly meetings of C. Flew also criticised several of the other philosophical proofs for God's existence.