"The disease afflicting the modern world," wrote Jacques Maritain, "is above all a disease of the intellect." How serious is this disease? Scripture has adequately warned us: "If your eye is worthless, your whole body will be in darkness" (Matt. 6:23; Luke 11:34). The mind provides light so that we can see where we are going and know what we are doing. Who would drive an automobile with his eyes shut? Driving while under the influence of alcohol is a criminal offense, underscoring the importance of a clear head and a sound mind. Yet, it is all too common for people in our generation to live under the influence of a culture that disdains clear thinking and sound judgment, a culture that puts appetite before understanding, desire ahead of thinking, and impulse over reason. A certain primacy naturally belongs to the intellect according to the common sense maxim that we should think before we act. Reason's place of primacy must be re-instated. David Hume, a philosopher known for his intractable skepticism, stated in his Treatise on Human Nature, that "Reason is, and only ought to be the slave of the passions, and can never pretend to any other office than to serve and obey them." He saw reason as primarily an effective way of securing pleasure. Thus, he made pleasure paramount. Hume passed away in the year 1776, a year better remembered for the birth of a nation. Did Hume bequeath to America his skepticism together with his inversion of the natural order of reason and will? It is a tempting thought. Nonetheless, if passions are in the driver's seat, how can we avoid catastrophe? The sane man cherishes the blessings of reason. He utilizes language, thought, and common sense to his advantage. He honors the great institutions of marriage and the Church. He refuses to be at the mercy of his biology. At the same time, his life is not devoid of pleasure. "Nobody," St. Thomas Aquinas comments, following Aristotle, "can do without delectation for long." But pleasure should not cause dissipation, a condition that is hardly beneficial to the human being. Reason accepts pleasure in its rightful place and safeguards it from crossing over into pain. A little wine is fine, but too much can create a problem. The reasonable use of pleasure helps to ensure the enjoyment of additional pleasures. It is better to be sane than to be mad. This is an incontrovertible truism. It is preposterous (prae + posterius), in the original meaning of the word, to place appetite before reason. It is akin to putting the cart before the horse, or trying to put one's shoes on prior to putting on one's socks. We should take care to avoid putting first what should come second, or putting what is "posterior" before what should be "prior." It belongs to the wise man to place things in their proper order. The light of reason illuminates the path of life. This modest work is one man's plea for restoring reason to its place of primacy.