Copleston's family was Anglican (his uncle, Reginald Stephen Copleston, was a bishop of Calcutta), but he converted to Roman Catholicism while a pupil at Marlborough College, and became a Jesuit in 1930. He studied and later lectured at Heythrop College and, seeing the poor standard of philosophical teaching in seminaries, he was author of an influential nine-volume History of Philosophy (1946-75), which is highly respected.
He is well known for debating the existence of God with Bertrand Russell in a celebrated 1948 BBC broadcast; the following year he debated logical positivism and the meaningfulness of religious language with his friend the analytic philosopher A. J. Ayer.
One of Copleston's most significant contributions to modern philosophy was his work on the theories of St Thomas Aquinas. He attempted to clarify Aquinas's Five Ways (in the Summa Theologica) by making a distinction between in fieri causes and in esse causes. By doing so Copleston makes clear that Aquinas wanted to put forth the concept of an omnipresent God rather than a being that could have disappeared after setting the chain of cause and effect into motion.
From 1952, Copleston spent some of his teaching time at the Gregorian University in Rome, continuing to lecture at Heythrop until it joined the University of London system in 1970, whereupon he became the College Principal. After officially retiring in 1974 he continued to lecture overseas, especially at Santa Clara University in California. He was appointed a member of the British Academy in 1970 and CBE in 1993.
- Even if the actual systems of philosophy which have appeared in the philosophical thought of a given culture are historically conditioned, there may be ways of thought exemplified by past systems which remain a feature of a people's mentality or cultural outlook.
- If one refuses to sit down and make a move, you cannot be checkmated (in relation to Russell's stubborn belief about the existence of the universe).
- A History of Philosophy, vols. 1-9. IMAGE BOOKS 1993-1994
- (Volume I: Greece and Rome: From the Pre-Socratics to Plotinus)
- (Volume II: Medieval Philosophy: From Augustine to Duns Scotus)
- (Volume III: Late Medieval and Renaissance Philosophy: Ockham, Francis Bacon, and the Beginning of the Modern World)
- (Volume IV: Modern Philosophy: From Descartes to Leibniz)
- (Volume V: Modern Philosophy: The British Philosophers from Hobbes to Hume)
- (Volume VI: Modern Philosophy: From the French Enlightenment to Kant)
- (Volume VII: Modern Philosophy: From the Post-Kantian Idealist to Marx, Kierkegaard, and Nietzsche)
- (Volume VIII: Modern Philosophy: Empiricism, Idealism, and Pragmatism in Britain and America)
- (Volume IX: Modern Philosophy: From the French Revolution to Sartre, Camus, and Levi-Strauss)
- Schopenhauer: Philosopher of Pessimism, 1946 (reprinted London: Search Press, 1975.)
- Aquinas. Penguin, 1955.
- Contemporary Philosophy: Studies of Logical Positivism and Existentialism. Continuum, 1956.
- Philosophies and Cultures. Oxford University Press, 1980. ISBN 0-19-213960-6
- Religion and the One: Philosophies East and West Search Press, 1982. ISBN 0-85532-510-0