A man should be unbiassed and not to be conquered by external things: he ought to admire himself alone, to feel confidence in his own spirit, and so to order his life as to be ready alike for good or bad fortune. Let not his confidence be without knowledge, nor his knowledge without stedfastness: let him always abide by what he has once determined, and let there be no erasure in his doctrine. It will be understood, even tho I append it not, that such a man will be tranquil and composed in his demeanor, high-minded and courteous in his actions. Let reason be encouraged by the senses to seek for the truth, and draw its first principles from thence: indeed it has no other base of operations or place from which to start in pursuit of truth: it must fall back upon itself. Even the all-embracing universe and God who is its guide extends Himself forth into outward things, and yet altogether returns from all sides back to Himself. Let our mind do the same thing: when, following its bodily senses, it has by means of them sent itself forth into the things of the outward world, let it remain still their master and its own. By this means we shall obtain a strength and an ability which are united and allied together; we shall derive from it that reason which never halts between two opinions, nor is dull in forming its perceptions, beliefs, or convictions. Such a mind, when it has ranged itself in order, made its various parts agree together, and, if I may so express myself, harmonized them, has attained to the highest good: for it has nothing evil or hazardous remaining, nothing to shake it or make it stumble: it will do everything under the guidance of its own will, and nothing unexpected will befall it, but whatever may be done by it will turn out well, and that, too, readily and easily, without the doer having recourse to any underhand devices: for slow and hesitating purpose. You may, then, boldly declare that the highest good is singleness of mind: for where agreement and unity are, there must the virtues be: it is the vices that are at war with one another....