151. Why lust is harmful
151. WHY LUST IS HARMFUL
If the sins of the flesh are less blameworthy than spiritual sins, lust can’t do much harm, then, right?
. . . [C]arnal vices, namely gluttony and lust, are concerned with pleasures of touch in matters of food and sex; and these are the most impetuous of all pleasures of the body. For this reason, these vices cause man’s attention to be very firmly fixed on corporeal things, so that in consequence man’s operation (activity of soul) in regard to intelligible (spiritual) things is weakened—more, however, by lust than by gluttony, forasmuch as sexual pleasures are more vehement than those of the table. Wherefore lust gives rise to blindness of mind, which excludes almost entirely the knowledge of spiritual things. . . . The flesh acts on the intellective faculties . . . by impeding their operation (II-II,15,3).
One of the reasons lust is bad (not the only reason) is that it makes you stupid. Like any addiction, it blinds your vision to everything else and focuses it on the one thing that is the object of your addiction. St. Thomas often points out that lust harms the reason. This is much more serious if we remember that “reason” meant to him something much more broad, deep, precious, and human than it typically means to us (cold calculation). It is by “reason” that we know “spiritual things”.
But he also says that it does harm to the heart, and to love:
Now the fact that spiritual goods taste good to us no more, or seem to be goods of no great account, is chiefly due to our affections being infected with the love of bodily pleasures, among which sexual pleasures hold the first place (II-II,20,4).
St. Thomas was supernaturally preserved from all lust by a miraculous gift given to him after he refused to succumb to the prostitute his brothers put in his room when they imprisoned him to attempt to stop him from becoming a Dominican monk. St. Augustine, on the other hand, was “the playboy of the Western world” before his conversion. Yet both know and say the same thing about lust. Both the constantly sober person and the ex-drunk know the harm of drunkenness, in opposite ways.
Our reason, which is the only power in us that knows Truth, and our heart, which is the only power in us that loves, are thus both harmed by lust. Lust takes away clarity and reason from our mind and freedom from our will. And these two powers, mind and will, are the two most precious powers of the soul, and their objects—truth and goodness—are the only two things we absolutely and eternally need. That is why lust is no casual and relatively harmless sin.
Another reason is that lust is the most addictive of all sins. Love frees us, lust enslaves us. Its glue is the stickiest, and it is harder to free the soul from its clutches than from the clutches of the less attractive, cold-hearted sins like pride or idolatry or envy, because those sins are no fun at all. Yet the cold-hearted sins are in themselves more serious because they are more freely and deliberately chosen. So paradoxically, even though the sins of the flesh, especially lust, are less serious than spiritual sins in that they are less free and responsible, and have in them more of the element of addiction (though all sin is addictive; we are all sinaholics) and less of the element of free choice (though all sin is a free choice; otherwise we would not be responsible for it), yet this same fact explains why they are in another way more serious, more harmful, harder to purge. Their cause may be less (less free) but their attractions are greater.
Our world, far more than St. Thomas’, is chock full of lustaholilcs. The very word “lust” is typically treated as a joke, or else the alternative is assumed to be unattainable, undesirable, and incomprehensible. When everyone has a fever, a fever seems normal and 98.6 seems abnormally cool. Yet, as C. S. Lewis says, “when poisons become fashionable they do not cease to kill”.