In an influential essay called “The Ethics of Belief” the 19th century mathematician W. K. Clifford proclaimed the following epistemic rule. “It is wrong always, everywhere, and for anyone, to believe anything without sufficient evidence.”

Sometimes non-believers appeal to Clifford’s rule during arguments with believers, claiming that the burden of proof falls on believers. This troubles some believers who are philosophical novices, though it should not. For Clifford’s rule is doubly flawed.

First, as many philosophers have noted, Clifford’s rule would cast doubt on many beliefs few seriously question, among them, that other people have minds or that the world continues to exist while one sleeps.

Second, Clifford’s rule is self-defeating. He claims that it is wrong to believe anything upon insufficient evidence, yet he provides *no* evidence for the rule itself. By his own standard, Clifford must judge anyone who accepts his rule as wrong!

Given that, believers may, in Macbeth’s phrase, “beat backward home” appeals to “Clifford’s rule” (-under whatever name it might travel). Conversely, those who doubt the existence of God and wish to argue that it is unreasonable should abandon appeals to Clifford’s rule (because of its obvious flaws) and find another way to challenge theists.

[Cross-posted in Atheists, Christian Talk, Christianity Unplugged, Crossroads of Religion, and The Lion’s Den]