The scene is your favorite restaurant. Everything is just as you wish it to be. The seat is comfortable and stylish, the lighting is cozy but not too dim, and of course the food is delicious. With such order, everything is just right. Suddenly your dining partner begins acting strangely. Rather than eating like any normal person, he begins shoveling food not in his mouth, but in his nose. Disgusted, you stare in horror. You are mortified by his behavior and, in hushed tones, praying that no one else at the restaurant has witnessed it, you plead with him to stop arching his neck backward and inserting morsels of food and pouring drops of his beverage into his nostrils. Perhaps an unruly toddler would attempt such a spectacle, but this is an adult, someone who should know how to act in such an establishment.

After your supplications for him to cease and desist, his reply falls on you like a guillotine blade. “This is how I eat,” he says, “so I will not alter my manners.” Dumbfounded, you explain that eating is meant for nourishment, and he will not receive any nourishment unless he puts food in his mouth and swallows. He insists that he prefers his nasal method of nourishment because, although nonstandard, it provides him with a more enjoyable dining experience.

You decide to try one last time. You explain to him that the pleasure of eating and the purpose of nourishment are intimately connected. To seek the pleasure of eating in a way that utterly contradicts its purpose—nourishment—is barbaric, bestial, and, in a word, irrational.

Your dining partner is guilty of a most outlandish form of one of the seven deadly sins: gluttony. Gluttony, like lust, is a sin against the virtue of temperance. Temperance is the virtue that regulates the gratification of lower pleasures and the desires of sense according to reason (Summa Theologiae II-II: 141). That means that temperance keeps us from seeking something that feels good, tastes good, smells good, sounds good, or looks good too much or in the wrong way. Vices of intemperance like gluttony and lust are vices because they go against that rational order. They are irrational.

Now in order to understand this virtue and combat these vices, we have to begin with a simple admission. We have to admit that human beings have irrational desires for pleasure. It may seem strange to start with that admission, but it is important to do so. The vices of intemperance are real, and they affect people in varying degrees and in different ways. If you have ever tried to give up candy for Lent and found yourself confessing to breaking your Lenten promise on the Saturday after Ash Wednesday, then you know that controlling the appetite for pleasurable food is easier said than done. After all, that is precisely why there are so many different diet plans out there. People are looking for ways to control that desire for the pleasure of eating, to regulate it according to reason, and not to let their belly beat out their brain.

The same goes for pleasures of sex. The so-called “culture wars” in the media frequently revolve around sex because so many people have a high interest in the pleasure of sex, often devoid of the order of reason. So, we can admit it: human beings have irrational desires for pleasure that contradict the purpose of the pleasurable activity. We need temperance in all these areas.

When it comes to food, temperance takes the form of the virtue of abstemiousness. Abstemiousness moderates the desire and enjoyment of the pleasures of the table according to reason. When you found yourself out to dinner with a man putting food up his nose, you knew that the purpose of food was to nourish and sustain the life of the individual. Eating keeps us alive. Thankfully, food is tasty, so staying alive is fun. The problem of gluttony is when we eat too much or in the wrong way, in a manner that is not actually nourishing and life-sustaining. We put the pleasurable, tasty aspect of eating above the real purpose, which is nourishment. Abstemiousness is the virtue that puts the pleasure and purpose of food in the proper order.

There are several ways that gluttony can occur, so the virtue of abstemiousness must reorder our eating habits in those several ways. The most obvious form of gluttony is the gluttony of excess: overeating. The person who eats way too much becomes slovenly and sluggish in mind and body and, in time, does terrible damage to his health. Too attached to the pleasures of the palette, food ceases to nourish him but creates new and unexciting problems. The food helps him stay alive while simultaneously draining him of life. By the virtue of abstemiousness, he will begin eating food he enjoys, but not so much that it is harmful to him.

The opposite of excess is deficiency, and the opposite of overeating is self- starvation. This is the sin of those who are slaves to fashion that they see no food as pleasurable. They fear the nourishment and abhor the taste of food. Taken to an extreme, this can even become a disease, a tragic circumstance that requires great care and concern from friends and physicians. Abstemiousness would have them overcome this fear and develop a taste for good food that truly nourishes them.

A person can be gluttonous in other ways, too. It is gluttony to require only dainty, costly, or rare foods, and being excessively interested in the preparation, type, or uniqueness of the food; and it is gluttony to be too hard to please, requiring food of the highest quality on the most ordinary occasions. Of course, it is not wrong for a person with allergies to require some special course. In these cases, too, abstemiousness, a type of temperance, puts things in order. The abstemious person seeks relatively enjoyable food in an amount that nourishes him.

So the virtue of abstemiousness is one way that a person lives out the virtue of temperance. The abstemious person eats not like a beast but like a human with the gift of reason. He eats food that nourishes and sustains life, without putting the gratification of taste above the ultimate purpose of eating.

The virtue of chastity is similar. Chastity is temperance in the enjoyment of sex. Just as temperance with food places pleasure and purpose in proper order, according to reason, so also temperance with sex places pleasure and purpose in proper order. With abstemiousness, the brain governs the belly. With chastity, the mind governs sexual matters.

Humans are sexual creatures, so like other animals it takes two to tango. The tango has a clear purpose: procreation, the continuation of the species. Along with the purpose of sex comes sexual pleasure, making it more likely for the human race to procreate. As we saw in the case of food, in which the pleasure of eating is ordered to the nourishment and life of the individual, the pleasure of sex is ordered to the procreation of human life and the continuation of the species.

Chastity keeps pleasure and purpose in order, whereas the vice and sins of lust put them out of order. A person can be lustful by seeking the pleasure of sex excessively or in the wrong way, such that the person puts pleasure over purpose. I will not drag you through the whole litany of lust, but here are some of the ways that intemperance in sex shows itself, along with the remedy that the virtue of chastity provides.

The most basic sin of lust is fornication between an unmarried man and an unmarried woman. Even if the couple does not contracept, they are putting pleasure above purpose. The child that can come from such a union is disadvantaged, lacking a stable home in which to grow and mature to adulthood. Because the couple is not married, they have not made the commitment that is necessary for properly raising the child. The couple who fornicates places the sexual pleasure of the moment over and above the purpose of sex, at risk to themselves, the possible child, and the stability of their society. Adultery is more serious because it places pleasure above purpose and is a grave injustice to the person’s spouse. By breaking marital fidelity, the adulterer shatters the sacred sacrament that is set up to protect and promote procreation according to the order of reason.

Another variant of the sin of lust that is very common today, even among married couples, is the sin of contraception. By means of contraception, the couple engages in intercourse for the purpose of pleasure and consolation, while they explicitly exclude the possibility of procreation. In this case, again, pleasure trumps purpose, and the order of reason collapses in disarray.

The last sins of the vice of lust that I will mention here are the unnatural vices. These include sexual acts performed in solitude—manifestly for the sake of pleasure without regard to procreation. This sin is called “unnatural” because the natural course of sex is with a person of the opposite sex, such that procreation is possible. Another unnatural vice would be homosexual activity, in which the partners are not at all fit for procreation with each other. Such unnatural sins place pleasure above purpose in a highly irrational way because, quite simply, sex does not work that way. Unnatural sins of lust are like eating through the nose.

With so many ways of turning aside from the narrow path, chastity can keep a person going in the right direction. Chastity regulates the desire for sexual pleasure, directing a person toward the proper purpose of human sexuality, according to the order and dictates of reason. This means that humans apply reason to sexual desire—not to extinguish it, but to direct it. Recognizing that bodily desire can often point him or her in a disordered direction, the chaste person acts in a way that subordinates sexual desire and pleasure to the ultimate purpose of sexuality.

Chastity, then, takes different forms for different people. For a married couple, chastity means engaging in acts that are ordered toward procreation while avoiding acts that do not. For a single or celibate person, chastity means refraining from sexual activity, since the necessary state in life for sexual desire to be ordered properly—that is, the married state—is lacking.

Chastity is far-reaching for all people. In order to protect and exalt the great goods of procreation and spousal love, temperance also asks us to be modest in conversation and in clothing, to think good thoughts rather than impure ones, to treat others with dignity and respect. The virtue of chastity, then, also affects our interactions with others in all sorts of ways as we seek to promote holiness in ourselves and in our neighbors.

For some people, the virtue of temperance may appear burdensome and unthinkably difficult. It may even appear that temperance cuts off what they love most about being human. In truth, temperance is the virtue that expresses our true humanity. With temperance, we use what is most uniquely human—our mind and reason—to control the aspects of ourselves that we share with other creatures. Through temperance, we are free to live to the fullest because our humanity is not enslaved to its own flesh. This same temperance liberates us so that we can seek the highest and loftiest purposes for which God created us; that is, so that we can seek God himself. Temperance makes us more human and sets us up to “seek the things that are above, where Christ is, seated at the right hand of God” (Col 3:1).