William Hasker writes that his "tetralogy on Christian doctrine, together with his earlier trilogy on the philosophy of theism, is one of the most important apologetic projects of recent times." While Swinburne presents many arguments to advance the belief that God exists, he argues that God is a being whose existence is not logically necessary (see modal logic), but metaphysically necessary in a way he defines in his "The Christian God". Other subjects on which Swinburne writes include personal identity (in which he espouses a view based on the concept of a soul), and epistemic justification. He has written in defence of Cartesian dualism and libertarian free will. Although he is best known for his vigorous rational defence of Christian intellectual commitments, he also has a theory of the nature of passionate faith which is developed in his book "Faith and Reason". According to an interview Swinburne did with "Foma" magazine, he converted from Anglicanism (Church of England) to Eastern Orthodoxy around 1996: I don't think I changed my beliefs in any significant way. I always believed in the Apostolic succession: that the Church has to have its authority dating back to the Apostles, and the general teaching of the Orthodox Church on the saints and the prayers for the departed and so on, these things I have always believed. Swinburne's philosophical method reflects the influence of Thomas Aquinas. He admits that he draws from Aquinas a systematic approach to philosophical theology. Swinburne, like Aquinas, moves from basic philosophical issues (for example, the question of the possibility that God may exist in Swinburne's "The Coherence of Theism"), to more specific Christian beliefs (for example, the claim in Swinburne's "Revelation" that God has communicated to human beings propositionally in Jesus Christ). Swinburne moves in his writing program from the philosophical to the theological, building his case rigorously, and relying on his previous arguments as he defends particular Christian beliefs. He has attempted to reassert classical Christian beliefs with an apologetic method that he believes is compatible with contemporary science. That method relies heavily on inductive logic, seeking to show that his Christian beliefs fit best with the evidence. National Life Stories conducted an oral history interview (C1672/15) with Richard Swinburne in 2015 for its Science and Religion collection held by the British Library.