Some complain that contemporary philosophical debate is not substantive, or is too narrow, or is overly technical. Whether or not these complaints are fair in general, they do not apply to Richard Swinburne at all. Swinburne deals with philosophy's most substantive questions – about God and the soul – and makes his answers accessible to a general audience.
Swinburne is probably the pre-eminent contemporary philosopher of religion. His book The Existence of God (2004) is the most elegant defence of theism ever composed. His Is There a God? (2010) summarizes the previous book in an accessible way. Swinburne's Mind, Brain, and Free Will (2013) is one of the most sophisticated defences of substance dualism available. Are We Bodies or Souls? distils that book in an accessible way into about 170 pages of main text.
But the new book does not summarize all of his previous book: it focuses exclusively on the soul; there is no discussion of free will. And it does not only summarize: it perfects the treatment in various ways; the argument is clearer, and the organization is more streamlined. Readers will include not only a popular audience but professional philosophers too, and those familiar with the previous book will benefit from the new book.
It is divided into seven chapters. After a short introduction in chapter 1 setting out the plan of the book, chapter 2 fixes the terms at work throughout: substance, property, dualism, and so on. The chapter also presents and rejects materialist theories of mental properties: behaviourism, functionalism, identity theory, and so on. At about eight pages, the latter discussion will be too quick for many readers new to philosophy of mind. Swinburne's case for property dualism seems to me to be close to Jackson's knowledge argument; it's a pity then that he doesn't make explicit use of that famous and vivid argument.
Chapter 3 begins the case for the soul with an updated version of Swinburne's argument about personal identity. Various complex theories of personal identity are distinguished and dismissed. For example, the theory that there is the same person iff there is enough of the same brain must be rejected especially in light of fission cases. Swinburne doesn't put it quite this way, but the idea again seems close to a knowledge argument: we could know all the facts about the material stuff and not know where the person goes. In the end, the only option is a simple theory of personal identity: personal identity is not analysable in terms of body, brain, or psychology.
In light of a ‘principle of the identity of composites’, this means that we each have a crucial immaterial part – a soul. But the result so far is only that the soul is necessary for personal identity. Chapter 4 develops an argument to show that it is sufficient. This is none other than Descartes's famous argument that we are souls. Swinburne presents the Cartesian argument neatly, amends it to avoid a minor objection, and compares and contrasts the Cartesian and Thomist views of the soul – with the Cartesian view turning out superior.
The big and familiar objection against the Cartesian argument is that this kind of reasoning proves too much – that the morning star isn't the evening star, that water isn't H2O – because of a careless use of Leibniz's law or something like that. Chapter 5 tries to show that the Cartesian argument makes no such mistake. Whereas ‘water’ is (or once was) an uninformative designator, ‘I’ is an informative designator – in knowing what ‘I’ means, we know what it refers to. The argument here will probably be the trickiest for students (and professional philosophers) to follow. The chapter concludes with an argument for each soul having its own thisness.
With objections against the premises of the Cartesian argument answered, chapter 6 turns to the most popular objections directly against the conclusion: problems of body and soul interaction. Such a problem was raised early on against Descartes by Princess Elizabeth. In light of some general principles about the nature of belief and evidence, Swinburne argues for an interactionist dualism, with goings-on in the body causing goings-on in the soul, and vice versa. He responds especially to objections from the Libet experiments and causal closure of the physical.
The final chapter addresses a series of curious questions about souls: When do souls begin to exist? When do they cease to exist? Is more than one soul connected to a body where there is dissociative identity disorder or a split brain? What organisms have souls? Can science explain the connection between soul and body? In light of the thisness of each soul, Swinburne concludes that science cannot explain why this soul is connected to that body. Swinburne does not tell us here whether the connection needs an explanation and what the explanation might be.
In previous books, Swinburne argues that certain aspects of consciousness are best explained by theism. But God is barely mentioned in this book. The book should thus appeal to theists as well as atheists. To be sure, atheists might be more pressed to reject Swinburne's argument – so long as they think that theism would be needed to make sense of body–soul connections and that body–soul connections would have to be made sense of. But they would also need to show where exactly the argument goes wrong.
The book includes a short guide to further reading, recommending some books with opposite conclusions, including books defending materialism. However, Swinburne does not treat idealism, panpsychism, or neutral monism. Happily, recent metaphysics is increasingly open to views more radically at odds with materialism than is substance dualism. In light of these, philosophers today might need as much argument for the existence of mind-independent material stuff as they do for the existence of immaterial souls. While Swinburne provides no argument for the existence of bodies, the question hardly threatens his main conclusion: that we are souls, not bodies.
Does Swinburne's argument work? He succeeds in showing deep problems with alternative theories of personal identity. He succeeds in showing that there is more to the Cartesian argument and less to the objections than most philosophers have thought. In my view, the case is powerful and thought-provoking. I have no original objections. Some objections have already been made against Swinburne's larger book on the subject, especially by Lynne Rudder Baker (‘Swinburne on substance dualism’, European Journal of Philosophy, 6.2 (2014), 5–15) and Eric Olson (‘Swinburne's brain transplants’, Philosophia Christi, 20.1 (2018), 21–29). Swinburne does not tell us if these objections were fair to begin with or signal whether the present formulations avoid them.
Whether or not the argument is persuasive, Are We Bodies or Souls? is excellent. It deepens the debate for professional philosophers, and carefully introduces a wide audience to a big question, a big answer, and a big argument. It is especially useful for courses in metaphysics and philosophy of mind. While the moral of the book is that we should look beyond material externalities, I must remark that the book is magnificently produced by Oxford University Press – the cover is the most beautiful I have seen on a philosophy book.
