The first is the judging faculty, the faculty which determines not only what are the proper means for attaining any end, but also what ends are fit to be pursued, and what degree of relative value we ought to put upon each. This faculty Plato called, as it is very properly called, reason, and considered it as what had a right to be the governing principle of the whole. Under this appellation, it is evident, he comprehended not only that faculty by which we judge of truth and falsehood, but that by which we judge of the propriety or the impropriety of our desires and affections. The different passions and appetites, the natural subjects of this ruling principle, but which are so apt to rebel against their master, he reduced to two different classes or orders. The first consisted of those passions, which are founded in pride and resentment, or in what the schoolmen called the irascible part of the soul; ambition, animosity, the love of honour, and the dread of shame, the desire of victory, superiority, and revenge; all those passions, in short, which are supposed either to rise from, or to denote what, by a metaphor in our language, we commonly call spirit or natural fire. The second consisted of those passions which are founded in the love of pleasure, or in what the schoolmen called the concupiscible part of the soul. It comprehended all the appetites of the body, the love of ease and of security, and of all the sensual gratifications. It rarely happens that we break in upon that plan of conduct, which the governing principle prescribes, and which in all our cool hours we had laid down to ourselves as what was most proper for us to pursue, but when prompted by one or other of those two different sets of passions; either by ungovernable ambition and resentment, or by the importunate solicitations of present ease and pleasure. But though these two orders of passions are so apt to mislead us, they are still considered as necessary parts of human nature: the first having been given to defend us against injuries, to assert our rank and dignity in the world, to make us aim at what is noble and honourable, and to make us distinguish those who act in the same manner; the second, to provide for the support and necessities of the body. In the strength, acuteness, and perfection of the governing principle was placed the essential virtue of prudence, which, according to Plato, {239} consisted in a just and clear discernment, founded upon general and scientific ideas, of the ends which were proper to be pursued, and of the means which were proper for attaining them.