What, further, is to be said of the fact that pleasure belongs alike to the good and the evil, and that the base delight no less in their disgrace than do the honorable in fair repute? And therefore the ancients have enjoined us to follow, not the most pleasant, but the best life, in order that pleasure should be, not the, leader, but the companion of a right and proper desire. For we must use Nature as our guide; she it is that Reason heeds, it is of her that it takes counsel. [7] Therefore to live happily is the same thing as to live according to Nature. What this is, I shall proceed to make clear. If we shall guard the endowments of the body and the needs of Nature with care and fearlessness, in the thought that they have been given but for a day and are fleeting, if we shall not be their slaves, nor allow these alien things to become our masters, if we shall count that the gratifications of the body, unessential as they are, have a place like to that of the auxiliaries and light-armed troops in camp — if we let them serve, not command — thus and thus only will these things be profitable to the mind. Let a man not be corrupted by external things, let him be unconquerable and admire only himself, courageous in spirit and ready for any fate, let him be the moulder of his own life; let not his confidence be without knowledge, nor his knowledge without firmness; let his decisions once made abide, and let not his decrees be altered by any erasure. It will be understood, even without my adding it, that such a man will be poised and well ordered, and will show majesty mingled with courtesy in all his actions. Let reason search into external things at the instigation of the senses, and, while it derives from them its first knowledge — for it has no other base from which it may operate, or begin its assault upon truth — yet let it fall back upon itself. For God also, the all-embracing world and the ruler of the cosmos, reaches forth into outward things, yet, withdrawing from all sides, returns into himself. [8] And our mind should do the same; when, having followed the senses that serve it, it has through them reached to things without, let it be the master both of them and of itself. In this way will be born an energy that is united, a power that is at harmony with itself, and that dependable reason which is not divided against itself, nor uncertain either in its opinions, or its perceptions, or in its convictions; and this reason, when it has regulated itself, and established harmony between all its parts, and, so to speak, is in tune, has attained the highest good. For no crookedness, no slipperiness is left to it, nothing that will cause it to stumble or fall. It will do everything under its own authority and nothing unexpected will befall it, but whatever it does will turn out a good, and that, too, easily and readily and without subterfuge on the part of the doer; for reluctance and hesitation are an indication of conflict and instability. Wherefore you may boldly declare that the highest good is harmony of the soul; for where concord and unity are, there must the virtues be. Discord accompanies the vices.