“This is the monstrosity in love, lady,” Troilus tells Cressida in Shakespeare’s play, “that the will is infinite and the execution confined, that the desire is boundless and the act a slave to limit.” Human desire, in other words, is doubly infinite: We are perpetually unsatisfied when we get what we want, and we are capable of wanting anything at all.

Suppose Troilus is right. That would mean desire eventually must consume even itself. Indeed, in Troilus and Cressida, Ulysses says precisely that: Since appetite is “an universal wolf, / so doubly seconded with will and power,” it “must make perforce an universal prey, / and last eat up himself.”

I find this understanding of desire immediately plausible. It does not sit well, however, with the way that we Catholic thinkers typically talk about desire—categorizing some desires as natural and others as unnatural. It does not sit well with that most typical of Catholic ideas: natural law. If desire is doubly infinite, as Shakespeare suggests, and therefore self-consuming, what can it mean to speak of any desire as natural?

Of course, if human desire is infinite, then it is, in a sense, entirely natural for us to desire anything we can imagine or conceive. This, in turn, means our desires are naturally open rather than closed, protean rather than formed, awaiting direction rather than already under orders. The range of things on which human desire is focused is, as a matter of fact, infinite, and the plasticity of desire is distinctively human. Consider the desires of your dog, or of the crape myrtle tree in your yard. The desires of these creatures are not infinitely malleable, and the range they are capable of reaching is small.

The nature of human desire, then, is that no particular desire is natural. A full appreciation of human nature—a sort of meta-naturalism—properly denies the natural. And this denial applies even to the drives we have genetically: our urges for sex and food and violence. Even these are capable of formation, reformation, and deformation, to the point of their own ­erasure. This is why we have Casanovas and celibates, gourmands and hunger artists, torturers and pacifists.

If all this is true, then we ought not to talk as though it were not. You will hear it said, for instance, that the desire for political freedom is a natural human desire, or that heterosexual desire is natural, or that the desire for God is natural (theologians often say this). For that matter, you will hear it sometimes said that it is unnatural to eat horses and snails (the English like to say this, having in mind French culinary tastes), or that parental love for children is natural. Of course, such talk is deeply rooted in tradition, and it’s unlikely that we will stop. But we should understand that, even while we speak this way, we are not in fact more open to any particular configuration of desire than to another.

Or, at least, we have no particularly natural desires now—although, I want to argue, we did before the Fall and will again, after the resurrection to eternal life.

Theologians, especially my fellow Catholic theo­logians, may find this implausible. But we must begin with the fact that human desire has been deranged. Our desires have moved from order to chaos; they have been opened to the damnable as well as the beautiful. Following hard on the expulsion from the Garden (a place where both human desires and the things on which they focused were arranged beautifully and cultivated in accord with God’s passions), the Bible tells us, Cain envied and killed Abel.

That’s the way the human tale of desire begins—with blood and a hunger for taking from others what they have for no other reason than that they have it. And from this derangement comes, very rapidly, the evils of slavery, rape, genocide, and abortion, together with their many bloody cousins. We lack natural desire because our desires have been removed from their proper arrangement, their properly harmonious response to the fact that we are created beings. After the Fall, we suffer from derangement.

The word derangement can be taken to have two apparently opposed meanings. It has its standard sense of removing arrangement, order, and beauty. But we might also use the word to mean an enclosing, a restricting—a limiting of what is properly a larger range. And this double meaning is reflected in the double derangement of our desires. Derangements in the direction of openness—as when our desires are set free to wander in an open range without limits—necessarily cause a second derangement, this time in the direction of discipline and enclosure.

Our derangedly open desires can be directed to anything at all. But desire never seeks anything, exactly; it always seeks something in particular, though that something might be almost anything. Our sexual, gastronomic, and intellectual appetites are unbounded in what they might desire, but they will eventually focus on some particular desire. For these appetites to be configured, they will have to be narrowed, disciplined, and restricted—that is, deranged in the second sense of the word—from the infinitely open range in which they wander.

This configuration happens inevitably. The question, then, is not whether it will happen, but how, and whether the configuration will be beautiful or ugly. Our appetites for one another (to take just one example), derangedly open as they are now, may be configured toward necrophilia, in which we seek others only as dead.

Or they may be configured toward love, in which we seek others as the particular images of God that each of them is. Or they may be configured anywhere in between. The second derangement, the narrowing one, may aim at a reversal of the first derangement or at its intensification.

Consider hunger. This would appear an innate drive: The sucking reflex of the newborn is something close to a human universal. Still, that drive is almost weightless and formless. It floats nearly free of response to and desire for any particular food. Our hungers are instructed and formed over time by careful nurture. The breast is offered to newborns, and their positive responses to it and its gift of milk are encouraged.

As they grow, children experience their tastes being formed by local habit, custom, and discipline until they become, for instance, adults who appreciate and desire a dozen raw oysters washed down with a crisply citrus-tinged Pinot Gris and who are revolted by a dinnertime offering of roast cat. Or they may become eaters who are disgusted by cheese while eager to eat plantain fried in peanut oil. Every adult eater has gastronomic appetites of fantastic complexity, and every particular feature of that complexity has, among the necessary conditions for its existence, a local catechesis. None of these tastes is ­natural.

Consider, too, our desire to speak—the appetite for language, for responding to the words of others with words of our own. The catechetical story is the same, whether the children are speakers of Italian, with a taste for writing and reading sestinas, or speakers of English, with a taste for the rhythms of rap. Particular desires for words get configured in a vast edifice of culture, education, and native tongues. As with particular gastronomic choices, configured verbal desires that give delight to some will bore or disgust or puzzle others.

A useful example for understanding this distinctively human feature of desire is the fact of excess. To say of human desires that they are excessive is, first, to repeat that they are open to almost infinitely varying configurations. But it is also to focus attention on the insatiability of desire:

The human effort to configure and reconfigure and extend and elaborate desires is constantly transgressive exactly because it is excessive. Gastronomic desire does not find rest in adequate nutrition. If it did, there would be no chefs, no restaurants, no shelves groaning with diet and recipe books. Sexual desire does not find rest in procreation and loving intimacy. If it did, there would be no adulterers, no pornography, and very little romantic poetry.

The question, then, is how we should discriminate among the configurations of our excess. Which should we encourage, and which discourage? Almost all of us have been catechized—the Christian word is appropriate—in such a way that we have a meta-appetite, an appetite for disciplining both our own appetites and those of others into particular configurations.

Most parents, for instance, prefer to catechize out of their toddlers a desire to display and share their own excrement, a desire that many toddlers show at one time or another. Most teachers work hard to encourage the habits of mental discipline that they think will nurture the development of particular desired skills—literacy, say, or logic. At the same time, teachers work hard to discourage habits that will hinder the development of these skills. And doctors strive to change patterns of appetite, most generally those for a style of life directly productive of disease and death.

Similarly, we often find our own adult appetites in need of reconfiguration, and so we catechize ourselves—whether over something as trivial as an appetite for nicotine or as important as an appetite for self-aggrandizement. Judgments of these kinds, and the catechetical activities that go with them, are normative: They imply an understanding of what human flourishing and human corruption are like. Christians are like everyone else in this. We believe that Jesus Christ came so that we might have life and have it more abundantly. This can be paraphrased without significant loss, except in pithiness, by saying that Jesus Christ came so that our appetites might be configured in some particular way, our desires lent a certain weight—a weight that will turn us from death and fit us for life.

Each particular configuration of appetite has a temporal impetus: It is an element in a habitus, a mode of being in the world, that disposes people to move along its track. There is no inevitability about such movement. It is possible for a well-established habitus to be suddenly and radically reconfigured: Drunks may suddenly cease to drink, the generous may become miserly, and the violent may become peaceable. But this is not the usual story. Usually we continue moving in the direction we are heading.

The ten-year-old child living in Japan is likely to become a more proficient and polished user of Japanese. The man practiced at inflicting pain on others will, in the right context, become even more practiced. The weight of our catechized appetites drags us in a certain direction: The eyes of the glutton follow the food, while those of the devout seek the traces of God.

There is always, in such habits, an implied goal, which is the full development of the habit’s tendency. Christians, of course, believe that even good appetites cannot be developed fully on earth; they find their full and final development only when we see God face to face and know as we are known. Indeed, where the adjective natural is typically used to modify some ­pattern of appetite, we Christians might do well to ­substitute a phrase such as to be cultivated in response to divine gift.

Applied to “natural desire” for God, the substitution works well: The desire to know and see God is a configuration we can nurture or oppose. It can flourish or wither because of what we do or refuse to do, and its cultivation is undertaken with an eye to its heavenly result. To desire God is good for us because it prepares us for intimacy with him, which is what we are created for. To configure our desires in such a way that the desire for God becomes progressively less possible for us is to make ourselves less than we should be. In its extreme case, it is damnation.

Christians often say that human beings are disposed to configure appetite in a God-directed way, but we are, in fact, no more disposed to configure our desires that way than any other. This is, in part, why it is improper to speak of our desire for God as natural to us. That desire is just one configuration possible for us; it is no more natural to us than its opposite, which is a desire for the lack that is God’s absence. The cultivation of the desire for God, then, is not a human work independent of God; it is an instance of responsive gratitude to the gift of the very possibility of action.

An interesting question is whether this openness—this inchoateness of desire, this readiness for formation and malformation—is a good thing or a bad thing about us. Is this feature of human existence after the Fall something to be lamented and corrected, or are there features of it that warrant rejoicing—features that make it possible for us to be more fully conformed to God?

In Eden, before the Fall, human desires were not inchoately open in the way they are now. Adam and Eve’s desires were focused on God without need for catechesis, and the desire for God was as natural to them as a heartbeat. An inevitable concomitant of this natural focus, however, would have been a reduction in the range of desire’s texture and possible formation. There would have been neither need nor occasion for the range of gastronomic, verbal, or sexual appetites that are unavoidably open to us now.

The same is true in heaven. The saints’ natural desires are indefectibly fixed on God, formed in the single and maximally beautiful shape of praise. Desire’s heavenly range is, therefore, in one sense, very small: tightly aimed at a single focus. But because the Lord is in every sense infinite, desire’s removal from the open range of possibility that exists here below is not, in fact, a derangement in the direction of loss but, rather, a focus in the direction of infinite gain.

Like Adam and Eve, the saints in heaven have a natural desire for God, but the grammar of the faith requires us to say that there is, nevertheless, a deep difference between Edenic desire and heavenly desire. The difference is not of range but of history—a history that has intervened between paradise and heaven; a ­history of sin and death, violence and blood; a history in which we are fully implicated.

The absence of tears in heaven—an absence for which there is deep scriptural warrant—does not mean that this history has been erased or forgotten. The weight of it remains because the events that constitute it are real; it is not a shadow play that can be erased by heaven’s radiance. Those who love God in heaven are healed sinners; they include killers and rapists and torturers. Those who dwelled in the paradise at the beginning had not yet sinned and were not yet soaked in blood violently shed.

God’s embrace of each kind of lover is, therefore, correspondingly different. If it is true that there is more heavenly rejoicing over the lost sheep that is found than over the sheep that have not strayed, God’s embrace shows one important sense in which the history that began with the eating of forbidden fruit in the Garden and that will end in the heavenly city is a good one. God’s embrace of each kind of lover is a way of explaining Adam’s sin, and the consequent removal from us of a natural desire for God, as a felix culpa, a happy fault. To say this neither explains nor justifies sin and death. It simply indicates one thing that follows from the Fall’s derangements that should not be lamented but, rather, rejoiced in.

The derangement of human desire in the Garden opened human desire to an infinite range of possibility by making that desire inchoate. The secondary derangements I have described catechize this inchoateness into a vast variety of particular configurations. Each of these particular configurations is, to some extent, damaged, blood- and violence-threaded, idolatrous, lured by lack and absence.

But not every particular configuration is deranged to the same extent. My desire to sing the Sanctus and to receive the body and blood of Christ in humility, in the company of my brothers and sisters in Christ, is not, in these respects, on a par with my desire to dominate by intellectual violence my brothers and sisters in the university. I’ve been catechized into both desires, and both are alive and active in me, but one conforms me more closely to God, and the other damages me by separating me from God.

Catechized, secondarily deranged desires are, then, theoretically locatable in a hierarchy of goodness, although never easily and never without qualification and ambiguity. Among the products of desire deranged are some goods that otherwise would not have been. Consider the singing of a Bach cantata, or the flying buttresses of a Gothic cathedral, or the poetry of George Herbert, or the embrace of lovers long separated, or the gift of time and love to the dying, or the Christian assembly on its knees as bread and wine are consecrated on the altar. All of these fit with desires well catechized and divinely beautiful, and all of them would not have occurred without the Fall.

Such goods will, in some fashion, be taken up into heaven. Their beauty and complexity and order is the reason our theological rejection of the ordinary concept of natural desire is a lament linked with joy.

Catholic theologians and Thomistic philosophers will object to this understanding of the human situation, and their objections must be taken seriously. But consider this: Among the strongest currents of thought these days is one that encourages us to discover who we are and to act accordingly—to gaze with the inward eye on our glassy essence and respond to what we find there. That gaze yields a vast range of identities: of gender and sex and ethnicity, of trait and temperament and passion. If what I have argued is right, when we attempt to discover who we are in that way, we find only phantasms—creatures of the imagination that wither when we turn our imaginations away from them.

This rejection of the language of natural desire opens to us, instead, the truth that we are creatures—inchoate, unformed, and hovering over the void from which we were made—who must seek either to return to that void or to find happiness in the arms of the one who brought us forth from it. There is no glassy essence to discover; there is nothing but an unformed gaze that receives form only by looking away from itself and receiving the gift of being looked at by God.

Paul J. Griffiths holds the Warren Chair of Catholic Theology at Duke University’s Divinity School. This essay is adapted from his October 2008 lecture inaugurating his tenure.