Supertext: The textbook that changed my life

As everybody knows, the four-year undergraduate degree offered by Scottish universities is a triumph of British higher education. For me, it meant that, while making the most of the clement weather and other delights available at St Andrews, I could take additional subjects in the first two years, before specialising in history for the third and fourth honours years. Theology was thought to be not especially stressful, and I went so far as to buy one of the recommended texts, the second edition of John H. Hick's Philosophy of Religion , in Prentice Hall's Foundations of Philosophy series. It was neatly organised, clearly written and, at only 129 pages, very accessible to the newcomer. Judging by my marginal notes, I not only read the whole book, but also thought about quite a lot of it - sadly not something I can say for many of the textbooks that have blundered into my path.

Hick's book was an influence in three ways. First, it made me look up several long and peculiar-looking words that I hadn't come across when studying the history of the crusades or the development of the American constitution and that I now deploy to reduce pub conversation to a respectful silence. Sadly, I find I still have to look up "ontology", "teleology" and "eschatology", but at least I know that I knew them once.

Second, I was introduced to the complex, historical debates surrounding grounds for belief and non-belief. Religion was not simply dogma, to be swallowed whole or not at all, and faith not only the consequence of some blinding revelation. I became fascinated by natural theology and its critiques, and by the idea that nothing - not even religious faith - was beyond careful argument. The idea that the argument was open to all comers was appealing, too: "The atheist, the agnostic, and the man of faith all can and do philosophise about religion." In his second chapter, "Grounds for belief in God", Hick introduces the arguments of Anselm and Aquinas: wonderful, complex proofs for belief, yet built upon something so innately unprovable. Arguments for disbelief are covered in the following chapter, in the "responsible scepticism" of Durkheim, Freud and others, and of much modern science, which seeks to explain ostensibly religious experiences in ways that do not postulate a God.

Finally, acquaintance with Aquinas introduced me to his writings on morality and warfare. This has developed into a probably unhealthy obsession with the Judaeo-Christian tradition of the just war. It is by no means flawless, but as a framework for moral reflection on the resort to and use of armed force, I find much to admire in it.

Paul Cornish is director, Centre for Defence Studies, King's College London.