Indeed, when we think of the matter carefully it is doubtful whether the human mind would ever even have attained to the notion of ideal truth, with the correlative thought of the shortcomings or the limits of our ordinary knowledge, if it had not been for the moral life and the serious problem it sets before us as men--that of the complete satisfaction or the complete assertion of our human personality. We seek truth in the first instance because we wish to act upon certainty or upon adequate certainty, and because we feel that we must be determined by what appeals to our own convictions and motives, by what has become part of our own life and consciousness. It is only in fact because we will it, and because we want it, that the “ideal” exists--the ideal of anything, more certain knowledge about something, for example, or gratified curiosity, or satisfied desire, and so on. In every case, say, of the pursuit of an ideal we desire something or some state of things that does not yet exist. The actual, if indeed (which is doubtful) we can think of the actual merely as such, does not engender the notion of the ideal, although there is possibly a suggestion of the “ideal” in the “meaning” that we cannot, even in sense perception,[258] attach to the actual. Even science, as we call it, is very far from being a mere description of the actual, it is an ideal “construction” or “interpretation” of the same in the interest, not of mere utility, but of the wonder and the curiosity and the intellectual and aesthetical satisfaction of our entire personality, of our disinterested love of the highest truth.[259] A striking example of the part played by moral and personal factors in the evolution of truth may easily be found, as has already been suggested, in some of the circumstances connected with the evolution of the Platonic philosophy in the mind of its creator. Plato’s constant use of the dialogue form of exposition is of itself an expression of the fact that philosophy was always to him a living and a personal thing, the outcome of an intellectual emotion of the soul in its efforts after true knowledge and spiritual perfection. It speaks also of Plato’s essentially social conception of philosophy, as a creation arising out of the contact of mind with mind, in the search after wisdom and virtue and justice. And there is little doubt that his own discontent with the social conditions of his time and with the false wisdom of the sophists was a powerful impulse in his mind in the development of that body of intellectual and ethical truth for all time that is to be found in his works. The determining consideration, again, in the arguments for immortality in the _Phaedo_ is not so much the imperfect physical and theoretical philosophy on which they are partly made to repose as the tremendous conviction of Plato of the supreme importance of right conduct, of his belief in the principle of the “best.”