In one sense, then, it is plainly not true that all our true ideas are useful. But there still remains a perfectly legitimate sense in which it might be true. It might be meant, that is, not that every _occurrence_ of a true idea is useful, but that every true idea is useful on at least one of the occasions when it occurs. But is this, in fact, the case? It seems to me almost as plain that it is not, as that the other was not. We have seen that true ideas are not by any means always useful on every occasion when they occur; though most that do occur many times over and to many different people are, no doubt, useful on some of these occasions. But there seems to be an immense number of true ideas, which occur but once and to one person, and never again either to him or to anyone else. I may, for instance, idly count the number of dots on the back of a card, and arrive at a true idea of their number; and yet, perhaps, I may never think of their number again, nor anybody else ever know it. We are all, it seems to me, constantly noticing trivial details, and getting true ideas about them, of which we never think again, and which nobody else ever gets. And is it quite certain that all these true ideas are useful? It seems to me perfectly clear, on the contrary, that many of them are not. Just as it is clear that many men sometimes waste their time in acquiring information which is useful to others but not to them, surely it is clear that they sometimes waste their time in acquiring information, which is useful to nobody at all, because nobody else ever acquires it. I do not say that it is never useful idly to count the number of dots on the back of a card. Plainly it is sometimes useful to be idle, and one idle employment may often be as good as another. But surely it is true that men _sometimes_ do these things when their time would have been better employed otherwise? Surely they sometimes get into the habit of attending to trivial truths, which it is as great a disadvantage that they should attend to as that they should constantly be thinking of their own thoughts and blemishes? I cannot see my way to deny that this is so; and therefore I cannot see my way to assert positively that all our true ideas are useful, even so much as on _one occasion._ It seems to me that there are many true ideas which occur but once, and which are not useful when they do occur. And if this be so, then it is plainly not true that _all_ our true ideas are useful in any sense at all.