A fellow of Trinity College, Cambridge, and of the Royal Society, William Clifford (1845-79) made his reputation in applied mathematics, but his interests ranged far more widely, encompassing ethics, evolution, metaphysics and philosophy of mind. This posthumously collected two-volume work, first published in 1879, bears witness to the dexterity and eclecticism of this Victorian thinker, whose commitment to the most abstract principles of mathematics and the most concrete details of human experience resulted in vivid and often unexpected arguments. Volume 2 shows Clifford's thorough engagement with scientific thought as a method for illuminating ethical and moral questions. Essays such as 'Body and Mind', 'On the Scientific Basis of Morals' and 'The Ethics of Belief' all variously demonstrate Clifford's core tenet: that beliefs - whether they guide human action or scientific enquiry - 'can never suffer from investigation'.