But, in a particular case, the train which he would have caught but for his false idea may be destroyed in a railway accident, or something may suddenly occur at home, which renders it much more useful that he should be there, than it would have been for him to catch his train. Do such cases never occur? And is not the false idea sometimes useful in some of them? It seems to me perfectly clear that it is _sometimes_ useful for a man to think his watch is right when it is wrong. And such instances would be sufficient to show that it is not the case that every idea of ours, which is ever useful, is a true idea. But let us take cases, not, like these, of an idea, which occurs but a few times or to one man, but of ideas which have occurred to many men at many times. It seems to me very difficult to be sure that the belief in an eternal hell has not been often useful to many men, and yet it may be doubted whether this idea is true. And so, too, with the belief in a happy life after death, or the belief in the existence of a God; it is, I think, very difficult to be sure that these beliefs have not been, and are not still, often useful, and yet it may be doubted whether they are true. These beliefs, of course, are matters of controversy. Some men believe that they are both useful and true; and others, again, that they are neither. And I do not think we are justified in giving them as certain instances of beliefs, which are not true, but, nevertheless, have often been useful. But there is a view that these beliefs, though not true, have, nevertheless, been often useful; and this view seems to me to deserve respect, especially since, as we have seen, some beliefs, which are not true, certainly are sometimes useful. Are we justified in asserting positively that it is false? Is it perfectly certain that beliefs, which have often been useful to many men, may not, nevertheless, be untrue? Is it perfectly certain that beliefs, which are not true, have not often been useful to many men? The certainty may at least be doubted, and in any case it seems certain that some beliefs, which are not true, are, nevertheless, sometimes useful.