Much contemporary moral philosophy is highly abstract, with technical arguments advanced on issues that appear far removed from ordinary life. But not all academic ethics has this form. The field of practical ethics has flourished over the last four decades, bringing philosophical techniques to bear on ethical issues in medicine, animal husbandry, climate change, and global poverty. Peter Singer is the movement’s central figure, with his Practical Ethics, first published in 1979, now in its third edition.

While by no means a theoretical work, the contours of Singer’s commitment to utilitarianism can be discerned in his new book, The Most Good You Can Do. Originating in the work of Jeremy Bentham, John Stuart Mill, and Herbert Spencer, utilitarianism says that the morally best action in every situation is the one that maximises happiness. Utilitarianism is one formulation of consequentialism, the theory that actions are to be judged by their consequence rather than by, say, their adherence to God’s word or, as Kant thought, by their relation to duty.