But the main fact which we are bound to remember is that it is impossible to pay for the exercise of any one faculty by the pleasure derived from the exercise of another; that each faculty is legitimately paid only in its own coin. If you ask a horseman who has just returned from an exhilarating ride what compensation he expects to receive for the exercise he has taken, he will probably look at you in blank amazement, with grave misgivings as to your sanity. If you ask a scientist what reward he expects to receive for the pursuit of knowledge, he will answer you, if he is an expert in the use of his intellect, that he expects no ulterior reward of any kind; that not positive knowledge so much as the sense of growth in the attainment of knowledge is the highest reward which he can imagine. And the same answer you will get from a person who is expert in the use of his moral faculty, namely, that not virtue so much as growth in virtue, not the results achieved by the exercise of the faculty, but the successful exercise itself is the supreme compensation. I have used the word "expert" in all these cases, and precisely "there's the rub." The reason why many persons cannot get themselves to believe that the exercise of the mental and moral faculties is a sufficient reward is because they are not expert, because they have not penetrated far enough along the lines of knowledge and virtue to obtain the satisfactions of them. But the same applies to the tyro in any pursuit. A rider who has not yet acquired a firm seat in the saddle will hardly derive much pleasure from horseback exercise. An awkward, clumsy dancer, who cannot keep step, will get no pleasure from dancing. There is no help for the tyro, no matter in what direction he aims at excellence, except to go on trying until he becomes expert. I have said that each faculty is sovereign in its own sphere, that each provides its proper satisfactions within itself and does not borrow them from the domain of any of the others. Nevertheless we are constrained to admit the important truth that is contained in the saying of Saint Paul. And this truth, it seems to me, may be formulated in the words that, while physical pleasure is not the reward of virtue, virtue ought to be regarded as the condition _sine qua non_ of the enjoyment of physical pleasures--at least, so far as the distribution of such pleasures is within the power of the educator or of society.