Cambridge mathematician and essayist. He is remembered in philosophy for the spirited essay ‘The Ethics of Belief’ (1879) defending an uncompromising religious agnosticism: ‘It is wrong, always, everywhere, and for anyone, to believe anything on insufficient evidence’. The essay brought an attempted rebuttal by William James, in his essay ‘The Will to Believe’ (1897), which itself, however, looks too much like a defence of wishful thinking to be convincing.
http://www-history.mcs.st-andrews.ac.uk/Biographies/Clifford.html A biography of Clifford, including his contributions to science, mathematics, and philosophy
http://www.des.emory.edu/mfp/james.html#will James's ‘The Will to Believe’, with commentaries on their debate