"it is wrong, always, everywhere, and for anyone, to believe anything upon insufficient evidence." William Kingdon Clifford, 1879 in the Ethics of Belief.
It is a summation of a rational argument on the ethics of faith and belief without evidence. It has a corollary, all belief without sufficient evidence is irrational. This statement provoked some debate when it came up in the philosophy of logic class, those that argued for watering it down failed to do so without resorting to logical fallacies.
In logic, an appeal to faith is a logical fallacy.







