For one thing, a conviction of the continuity of individual existence beyond the grave, in other earth-lives, more or less similar to the present life, affects the whole question profoundly. For we may at once infer that knowledge accumulated now, but not immediately used, may be used later on. And indeed this idea quite agrees with what many analogies from Nature suggest. Youth is the time for study; maturer age brings other duties. Let us compare a lifetime with a day. In the morning a man studies many subjects; but after noon he shuts his books, never thinks of them again, and spends the remainder of the day in other occupations, followed by recreation and ending in sleep. Has his labor been wasted? Nay, for he will resume it next morning. Can we not apply this analogy to the case of the young person whose education has had, or seemed to have, no immediate practical result? We thus see how limited views as regards the duration of life may influence the question. But there are other limitations in our views; let us see how these in turn may affect the question. We are accustomed to pay too much attention to a man's capacity as a separate individual, and not enough to his capacity as a part of a whole. No being in the universe is entirely separate from other beings however much he may try to make himself so or imagine himself to be so. This is especially applicable to Mind. How much of our mind is our own? It has been argued that Mind is a kind of common atmosphere, in which all partake, and that thoughts are interchanged freely, the notion that they belong particularly to oneself being chiefly an illusion. The more this is true, the more it must be true that in teaching one person we are in reality teaching many persons, teaching mankind in general. Does a teacher teach persons or minds? To him it often seems as if he were developing Mind, and the distinction of personalities is apt to disappear. Yet this attitude on his part may not be mere carelessness and indifference to the interests of his pupils; it may be founded on an intuitive perception of the fact that personality does not count for so much and that his pupils also have a collective capacity, an aggregate value, which counts for a great deal.