William Kingdon Clifford, mathematician and philosopher, was born in 1845, studied at Cambridge and later taught mathematics at University College, London. He made major contributions to non-Euclidean geometry and expressed original ideas on the subject of space and energy in his paper, On the Space Theory of Matter written in 1870. His work played a fundamental role in Albert Einstein’s General Theory of Relativity.

During his short lifetime he was well known for his antipathy to religion which arose from his own love of truth. He considered that ecclesiastical systems favoured obscurantism where the claims of sect were put above those of society.

At a time when religion was still reeling from the impact of Darwinism, Clifford was seen as yet a further dangerous influence to the established church.

Clifford died at the age of 34 in 1879, three years after he wrote his essay, The Ethics of Belief, in which he stressed the important principle, “It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.”

Clifford’s principle is not hard for modern humanists and atheists to understand. It was clearly an attack on the traditional theological approach to faith and belief where lack of evidence is considered a virtue.

Clifford was a Darwinist and certainly recognised that working hypotheses and assumptions are necessary steps in the process of understanding. He also knew that to test a hypothesis in the light of new evidence strengthens those worthy of survival. His views were controversial but the main thrust of the counter-arguments came in 1897 when William James published his Will to Believe.

These two works are complementary and represent the two sides of the never ending debate between evidentialism and faith. Both are written in a style that modern readers find laborious and Victorian. Clifford’s essay was a strong attack on beliefs that are “not founded on fair enquiry”. James took the view that the God hypothesis is acceptable on purely pragmatic grounds - implying that it doesn’t really matter whether God exists or not, the hypothesis is good for you!

The latter view may have appealed to the psychiatrist in James but was not at all effective in undermining Clifford, the thinker.

Further reading:
The Ethics of Belief and Other Essays (Great Books in Philosophy) by William Kingdon Clifford. Prometheus Books 1999 ISBN-10: 1573926914
The Will to Believe by William James. Bantam Doubleday Dell Publishing Group; 1st Image Books Ed edition. 1997 ISBN-10: 0385480466