Men leave error undisturbed, because they accept in a loose way the
proposition that a belief may be 'morally useful without being
intellectually sustainable,' They disguise their own dissent from
popular opinions, because they regard such opinions as useful to other
people. We are not now discussing the case of those who embrace a creed
for themselves, on the ground that, though they cannot demonstrate its
truth to the understanding, yet they find it pregnant with moralising
and elevating characteristics. We are thinking of a very different
attitude--that, namely, of persons who believe a creed to be not more
morally useful than it is intellectually sustainable, so far as they
themselves are concerned. To them it is pure and uncompensated error.
Yet from a vague and general idea that what is useless error to them may
be useful to others, they insist on doing their best to perpetuate the
system which spreads and consecrates the error. And how do they settle
the question? They reckon up the advantages, and forget the drawbacks.
They detect and dwell on one or two elements of utility in the false
belief or the worn-out institution, and leave out of all account the
elements that make in the other direction.

Considering how much influence this vague persuasion has in encouraging
a well-meaning hypocrisy in individuals, and a profound stagnation in
societies, it may be well to examine the matter somewhat generally. Let
us try to measure the force of some of the most usual pleas for error.

I. A false opinion, it may be said, is frequently found to have
clustering around it a multitude of excellent associations, which do far
more good than the false opinion that supports them, does harm. In the
middle ages, for instance, there was a belief that a holy man had the
gift of routing demons, of healing the sick, and of working divers other
miracles. Supposing that this belief was untrue, supposing that it was