Richard Swinburne offers an original treatment of a question at the heart of what makes a belief rational, or justified in holding? He maps the rival accounts of philosophers on epistemic justification ("internalist" and "externalist"), arguing that they are really accounts of different concepts. He distinguishes between synchronic justification (justification at a time) and diachronic justification (synchronic justification resulting from adequate investigation)--both internalist and externalist. He also argues that most kinds of justification are worth having because they are indicative of truth; however, it is only justification of internalist kinds that can guide a believer's actions. Swinburne goes on to show the usefulness of the probability calculus in elucidating how empirical evidence makes beliefs probably true.
Richard G. Swinburne is an Emeritus Professor of Philosophy at the University of Oxford. Over the last 50 years Swinburne has been a very influential proponent of natural theology, that is, philosophical arguments for the existence of God. His philosophical contributions are primarily in philosophy of religion and philosophy of science. He aroused much discussion with his early work in the philosophy of religion, a trilogy of books consisting of The Coherence of Theism, The Existence of God, and Faith and Reason.