Philosophy

These nine chapters, commissioned on the initiative of the Philosophy section of the British Academy, address fundamental questions about time in philosophy, physics, linguistics, and psychology. Are there facts about the future? Could we affect the past? Physics, general relativity and quantum theory give contradictory treatments of time. So in the search for a theory of quantum gravity, which should give way: general relativity or quantum theory? In linguistics and psychology, how does our language represent time, and how do our minds keep track of it?

Bayes' theorem is a tool for assessing how probable evidence makes some hypothesis. The papers in this book consider the worth and applicability of the theorem. The book sets out the philosophical issues: Elliott Sober argues that there are other criteria for assessing hypotheses; Colin Howson, Philip Dawid, and John Earman consider how the theorem can be used in statistical science, in weighing evidence in criminal trials, and in assessing evidence for the occurrence of miracles; and David Miller argues for the worth of the probability calculus as a tool for measuring propensities in nature rather than the strength of evidence. The book ends with the original paper containing the theorem, presented to the Royal Society in 1763.

Do humans have a free choice of which actions to perform? Three recent developments of modern science can help us to answer this question. First, new investigative tools have enabled us to study the processes in our brains which accompanying our decisions. The pioneer work of Benjamin Libet has led many neuroscientists to hold the view that our conscious intentions do not cause our bodily movements but merely accompany them. Then, Quantum Theory suggests that not all physical events are fully determined by their causes, and so opens the possibility that not all brain events may be fully determined by their causes, and so maybe — if neuroscience does not rule this out — there is a role for intentions after all. Finally, a theorem of mathematics, Gödel's theory, has been interpreted to suggest that the initial conditions and laws of development of a mathematician's brain could not fully determine which mathematical conjectures he sees to be true. The extent to which human behaviour is determined by brain events may well depend on whether conscious events, such as intentions, are themselves merely brain events, or whether they are separate events which interact with brain events (perhaps in the radical form that intentions are events in our soul, and not in our body). This book considers what kind of free will we need in order to be morally responsible for our actions or be held guilty in a court of law. Is it sufficient merely that our actions are uncaused by brain events?

This book comprises three main chapters on Descartes, Spinoza and Leibniz, with extensive responses. It explores the common ground of the great early-modern rationalist theories, and provides an examination of the ways in which the mainstream Platonic tradition permeates these theories. One chapter identifies characteristically Platonic themes in Descartes’s cosmology and metaphysics, finding them associated with two distinct, even opposed attitudes to nature and the human condition, one ancient and ‘contemplative’, the other modern and ‘controlling’. It finds the same tension in Descartes’s moral theory, and believes that it remains unresolved in present-day ethics. Was Spinoza a Neoplatonist theist, critical Cartesian, or naturalistic materialist? The second chapter argues that he was all of these. Analysis of his system reveals how Spinoza employed Neoplatonist monism against Descartes’s Platonist pluralism. Yet the terminology — like the physics — is Cartesian. And within this Platonic-Cartesian shell Spinoza developed a rigorously naturalistic metaphysics and even, Ayers claims, an effectually empiricist epistemology. The final chapter focuses on the Rationalists’ arguments for the Platonist, anti-Empiricist principle of ‘the priority of the perfect’, i.e. the principle that finite attributes are to be understood through corresponding perfections of God, rather than the reverse. It finds the given arguments unsatisfactory but stimulating, and offers a development of one of Leibniz’s for consideration. These chapters receive informed and constructive criticism and development at the hands of, respectively, Douglas Hedley, Sarah Hutton and Maria Rosa Antognazza.