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Interviews, Longreads

The Two Will Become One Flesh: An Interview with Alexander Pruss

Alexander Pruss

A Roman Catholic philosopher muses on how the scriptures and the tradition think about sex and love.

Professor of Philosophy, Baylor University
July 30, 2018

A PhD in Mathematics and a PhD in Philosophy walk into a coffee shop. “Table for one?” the waitress asks. How is it possible, you wonder? It might be easier to imagine if you were Alexander Pruss, both an eminent public philosopher and a brilliant mathematician. Dr. Pruss has taught for many years at both Georgetown University in Washington, D.C. and at Baylor University in Waco, Texas. A Roman Catholic, he has dedicated his career(s) to understanding the witness of the Church and the scriptures to the “good life,” both private and public.

Today, we’re sharing a conversation between Dr. Pruss and CCT’s Evan Rosa on his 2012 book, “One Body: An Essay in Christian Sexual Ethics.” Enjoy.

Evan Rosa: What got you interested in sexual ethics? In particular, what fostered that interest to the point where you felt it would be a good thing to write a book on it?

Alexander Pruss: About 16 years ago, I was a first‑year graduate student in Philosophy. I was doing some Internet apologetics and somebody challenged me to defend an aspect of traditional Christian sexual morals. I had an insight. I really liked that insight.

Over the 16 years, much of my work has been working out that insight that sexuality is about a union as one body. I’ve been working on and off on that. I have also, over the years, been teaching an undergraduate philosophy of love and sex class, both here at Baylor and at Georgetown University, so I’ve been bouncing ideas off the students.

I think in our time, among Christians, sexuality is one of the major controversies. There were times in the history of Christianity when it was over the divinity of Christ or other subtle points of the incarnation. Right now it’s, to a great degree, over sexuality. It is very important for the church to address this. That has been one of my main motivations.

What are sexual ethics and why are they important?. Why is it important for not just a Christian scholar but a lay person to be familiar with sexual ethics and have a sexual ethic of their own?

Ethics is the study of what the good and right human life is. Sexual ethics is the study of the good and right human sexual life. In sexual ethics, we look at what the point of sexuality is, and then try to figure out, in light of that, how humans should live the sexual aspects of their life.

Christianity’s often said to be a religion of love, but love comes in many different forms. There’s love between parents and children, between friends, between colleagues, and between erotic lovers, between husband and wife. That is one of the central forms of human love.

If we get sexuality wrong, we distort one of the central forms of human love. That simply can’t be acceptable to anyone whose religion claims to be centered on love.

If we get sexuality wrong, we distort one of the central forms of human love. That simply can’t be acceptable to anyone whose religion claims to be centered on love.

You say in the book that sex as a practice, as an experience, is much different and more meaningful than the practice of shaking hands, or a high five, or perhaps plenty of other practices. I’m wondering what the meaning of sex is. What is that deeply meaningful significance?

I think everyone can see that sex is meaningful. No matter how promiscuous somebody may be, they don’t have sex with the same level of casualness with which they shake hands. You shake hands with a very large variety of ages of people, sexes of people, different levels of attractiveness, but sex isn’t like that. I think sexual intercourse joins two people into one body.

Men and women are reproductively incomplete on their own. Reproduction is the one and only fundamental biological function that we adult humans cannot perform on our own, and only when joined together in intercourse as one body does a man and a woman become a complete reproductive whole.

I think this joining matters very deeply for at least two reasons. First, it matters because human reproduction doesn’t just produce another animal. It is something whose very nature is to produce persons in the image and likeness of God.

I think this makes a couple’s forming a reproductive whole, even when their reproductive whole doesn’t result in children, be something sacred. It is something designed for producing persons in the image and likeness of God.

It also matters because this physical union as one body expresses a lifelong union of the two as persons. They may not live up to what they’re expressing, but that is what it expresses.

Would you mind saying a bit more about what it is to express the expression of a person? What about an act of love is expressive of a person?

One of the most obvious ways in which we express ourselves is in words, but words can’t be the only way in which we express ourselves. For one, to learn words we have to have some other way of expressing ourselves. When we teach words to children, we have to express ourselves through gestures to them, through pointing things out.

There are ways of expressing that aren’t just words, and some of these we say are very deep. Facial expressions are a very deep way of expressing oneself not in words, and I think a sexual union is one of those gestures that have a deep meaning.

Contemporary society has split sexuality from love, both in theory and practice. We’ve also split sexuality from marriage, to a certain extent. What is at work in popular culture’s separation of sex from love and marriage, and what is the appropriate Christian perspective and response?

I think one of the things at work is fear. When I talk with students about marriage and cohabitation, I see that fear. A fear of being joined to stick with another person for life. This is a scary thing. Yet, the other person that we are afraid of being stuck with is actually somebody in the image and likeness of God. God was not too afraid to join with us on earth for life himself.

One response to culture is for Christians not to be afraid. Not to be afraid of marriage. Not be afraid of the sacrifices and joys that this union brings, but to give our culture compelling examples of the beauty of lifelong marital commitment, both when it is hard and when it is easy in a way that makes people see that this union actually does answer deep desires in the human heart.

The other thing that I think is at work here is there’s a separation between the mind and the body, seeing the body as having whatever meaning we want it to have. Our culture has worked hard to separate the feelings of sex—the pleasure—from the bodily reality of being in a union of persons as a reproductive whole.

Society has tried to make sex into pleasant recreation. The contraceptive revolution has much of the responsibility for this.

Here, the Christian community needs to be clear on the fact that sex, even when it does not succeed in procreation, is precisely the activity that humans reproduce through, the activity that joins two in a complete reproductive whole, and therefore makes it appropriate for them to remain together for life.

Until the beginning of the 20th century, Christians—whether Catholic, Protestant, Orthodox—were very clear on the importance of the connection between sex and reproduction, and sex and lifelong union. We should restore this understanding.

These connections between sex, lifelong interpersonal union, and reproduction lead to a deeper joy in sex rather than the temporary joy found in temporary encounters.

Let’s elaborate on some of those points.  You made an analogy to the incarnation, God’s joining himself to mankind. Can that function as an analogy for marriage, love, and sex between a man and a woman?

There is, in love, a tendency towards equality. When parents raise children, they want the children to eventually be their equals and maybe even sometimes their superiors. I think this is very important to marital love, striving for equality with the other. It’s also really clear in the incarnation. God becomes one of us, our brother. That is how he expresses his love for us.

How far does the analogy go? God becomes one of us. He becomes our brother in Christ. How does that map onto the marriage and the sexual union? Exactly what do you have in mind when you make reference to the “one body” union between two human persons?

One of the messages of the incarnation is that the body matters. The Gospel of John starts by telling us that the word became flesh. It didn’t just become human. It became flesh. The text is emphasizing the bodily nature of this. It does this against the Gnostics, who thought that, at most, Christ only appeared to become flesh. By becoming flesh, He redeems the body.

In the Eucharist, Christ offers his body to us. The New Testament continually describes the church as the body of Christ. We get a picture of the body as something sacred, a temple of the Holy Spirit.

Of all the forms of love, romantic love is what is most directly tied to the sacred mystery and beauty of the human body.

The body is that through which we can present ourselves to others as gifts in sexuality. This is something that Pope John Paul II preached often. To be one body is to work together as one body. This can happen very concretely in the bedroom when the couple engages in this very human activity of joining into a reproductive whole.

It also happens in other important ways when couples work together, especially, but not only, in raising and educating children. It is what happens when, as a church community, we work together bringing the good news of Christ to the lonely and being Christ’s hands for the poor.

Is that a functional union that you have in mind as opposed to a metaphysical union? That can often be a difficult distinction to make, especially to someone who’s not trained philosopher or theologian.

I’ve wondered a lot about how much the union as one body is to be taken literally and how much of it is a metaphor that gets at a very deep and important truth. I’m not completely clear on what the answer to that is.

In the church, which is described as the body of Christ, it seems to be something very deep and important. I think it has a deep metaphysical role in atonement, actually, because it is by being joined with Christ that His merits become ours. That His suffering atones for our sins.

That suggests that there is something like a metaphysical component to our union with Him, so that when He suffers on the cross, it is, in some way, as if we have suffered on the cross. I don’t know exactly how metaphysically literal we want to be about there being this further entity that comprises Christ and the people, and how much this is just a very deep metaphor.

I have a similar kind of wonder about sexual union, how much that is. Some biological organisms join together into something that has shape. For instance, slime molds join together into a fruiting body and you get all these little cells coming together. They all initially start as separate organisms, but they come together.

Some have the function of being a stalk that raises the others up, and the ones on top then have the function of sending out spores for reproduction. There, together they seem to be working very much as a single organism. But, on the other hand, they have a stage of their life when they are separate biological organisms.

I think biologists generally tend to think that the fruiting body of them is a colony rather than a new biological organism, but one could very well try to think about it the other way. I think there’s something like this going on. I think, for the ethical questions, it may not matter that much how much of it is a deep and important metaphor and how literal it is.

For me, as a metaphysician, it’s a very interesting question, and I’m inclined to go somewhat on the side of the metaphorical.

Of all the forms of love, romantic love is what is most directly tied to the sacred mystery and beauty of the human body.


I’d like to go back to the word agape. It doesn’t take long before, in some sermon or in some personal Bible study, you’re going to come across the word agape. It’s often portrayed as something other than, something separate. It’s one of the several words  which get translated as “love” from Greek. What is agape and how does it frame your study?

I think we’ve all heard, maybe in sermons or elsewhere, that Greek has a number of terms for love whereas English is supposedly impoverished, having only “love.” I think that’s actually mistaken. It may be true of classical Greek, but in the New Testament the two main terms for love are philia and agape.

As far as I can tell, looking at how these two words are used, they’re almost entirely interchangeable, and they cover the whole range of what the English word “love” covers.

The Greek translation of the Song of Songs, which is a very erotic song, describes sexual love as agape. The New Testament uses agape for just about every kind of love, including the love between spouses. In the Bible, the word agape doesn’t mean a special kind of love.

Even though there isn’t a separate word for it, the New Testament clearly does have the idea of deeper love that Christians are called to, a love that reflects God’s love for us. Jesus talks of how we should love our enemies, and that even the pagans love their friends. There’s a distinction. There’s something that Christians are called to.

God loved us for our own sake even while we were His enemies. He doesn’t need anything from us but desires to be united in love with us. He desired it to such a degree that He sent His son to die for us and be one of us. To return this love requires grace.

We return this love, both by loving God but also by loving our neighbor. There’s sort of this deep puzzle. How can we love God? To love somebody requires that we do good things for them, but God doesn’t need any good things. He’s in no way benefited by us.

Thomas Aquinas has a brilliant solution to this. He thinks there are two ways we can benefit somebody. We can directly benefit them by doing something that’s directly good for them, but we can also indirectly benefit a person by doing good things for those that that person loves. That’s a way in which we can do good things for God. By loving our neighbor whom God loves.

The well‑being of our neighbor is, in some extended sense, a part of God’s well‑being. This grace that God gives to return His love, it doesn’t, I think, create a new separate kind of love. It transforms our natural loves. It takes the love between friends or the love between spouses and makes that love into a better image of divine love.

Grace transforms natural, human, erotic love into a self‑sacrificing love, an unselfish love that is an image of God’s love for us, a love where delight in the other person is also a delight in God.

It’s also a love in which one is willing to sacrifice this delight and the joy of this life when one is called to it.

Let’s think about that question about the public nature, whether sexuality is inherently morally public, because there’s clearly a very private nature to one’s sexual life. Yet, when Wendell Berry makes an economical, moral, political statement about the deep importance of sex: When we privatize sex, when we make it too much about an individual or just one couple, that does a disservice to the community because something about sexuality is deeply public. What are your thoughts on that?

The social philosopher, Robert Nozick, has a really fascinating essay on romantic love. He sees romantic love as involving the joining of two into a we. You have two I’s and they become a we.

Just as we want to be recognized as individuals by society, by others, by friends, family as well as by political institutions, when we are joined into a we, we want to be recognized jointly as a unit by friends, family, strangers, and public institutions. There’s, I think, a natural social dimension to romantic love. That’s why weddings are normally public affairs.

For Christians, because our marriages should express Christ’s love for humanity, the public dimension is especially important. Marriage is a sacrament. It’s an action of the church.

Now, there are exceptional circumstances. Say circumstance of persecution, where it may be necessary to keep a marriage secret. For instance, in Nazi Germany, there may be good reasons to keep a marriage between someone of Jewish and non‑Jewish ancestry secret.

But, even when that happens, the couple, I think, would find that galling. There’s something missing there. It’s the best one can do, but there’s something that one wants. One wants a kind of publicness. I think the publicness of sexuality is something that the gay rights movement has got right.

If romantic love can be an appropriate form of love between persons of the same sex, then it is natural to seek public, legal recognition of this love, but I don’t actually think that romantic love is the appropriate form of love between persons of the same sex. I think friendship is the more appropriate form in that case.

Would you mind elaborating on that latter point, about friendship being a more appropriate love for members of the same sex?  People want to know what Christians think about homosexuality. Plenty of people have recently been arguing that there’s nothing morally wrong, there’s nothing even scripturally. You can’t find a good argument in New Testament, some claim. I would like to hear you elaborate on the joy of love as friendship and apply it, perhaps, to the circumstances of the question of homosexuality.

In romantic love, there’s a desire to join as one body. There’s a tendency to that. The kind of one body that the couple joins as is a reproductive whole. Some couples are incapable of that. Sometimes they may be of the opposite sex but be lacking in sexual organs and, hence, incapable of joining in their reproductive whole.

Another, perhaps more common way, in which a couple might be incapable of joining in their reproductive whole is because they are of the same sex and do not have a matched set of sexual organs that’s capable of joining them in this way.

Because the forms of love, I think, are defined in large part by the kind of union that they seek, this means that romantic love is not what is appropriate for persons of the same sex. I want to emphasize the importance of deep interpersonal friendships.

I think one of the primordial drives to sexual union comes from the desire not to be alone, but friendship also overcomes aloneness. Now, it’s very common to use the expression, “They are just friends,” but friendship isn’t a second‑best after romantic love. Jesus says, “There is no love greater than giving up one’s life for one’s friend,” so friendship is a central form of love.

It expresses God’s love in a somewhat different way from the way romantic love expresses it. Romantic love expresses a kind of intimacy and a kind of exclusivity. The exclusivity is really clear in the Old Testament. Whenever the Israelites worship idols, the Old Testament talks of that as adultery.

But friendship expresses the way that God’s love reaches out to multiple people. Friendship is inclusive in the way that romantic love is exclusive, and so it allows for modeling other aspects of divine love.

Could you say something about the importance friendship in a marriage, both between spouses and a community of friends?

I think early on in romantic relationships, the couple is often very much absorbed in each other and in a way in which they may ignore long‑standing friendships, but that isn’t the mature form of romantic love. The mature form of romantic love includes the romantic attachment, but it also includes a deep friendship with the spouse.

Friendship is naturally inclusive. It allows for more friends to be joined. Not an unlimited amount. Aristotle talks of friendship as being limited to the number of people that you could live with. I think what he means by live with, he doesn’t mean be under the same roof as. He means share a life with.

Friendship reaches out for a moderate number of other friends. Married people needed this kind of friendship with multiple other people, and there’s a danger, especially early on, in avoiding that and not having that. I think, typically, it tends to evolve in a fine way.

Grace transforms natural, human, erotic love into a self‑sacrificing love, an unselfish love that is an image of God’s love for us, a love where delight in the other person is also a delight in God.

We’ve already talked a little bit about homosexuality at a personal level. What can a Christian—or anybody, for that matter—who has same‑sex attraction, what are some practical considerations for that? How should any Christian deal with attraction in their singleness? How do you handle issues of high levels of intense sexual desire for other people?

One can give general advice about what not to do, like give advice not to engage in sexual activity that gives a feeling of being united, but doesn’t actually involve a union as one body or a lifelong union because of lack of commitment or because of a mismatch between the sexual organs.

Advice on what to do is usually very personal and is going to differ to a large extent from case to case. The traditional advice for deep moral struggle is prayer and fasting, and the Christian tradition emphasizes the fasting. Very literally, fasting is a powerful tool for fighting lust. To this I want to add the importance of friendship again.

Friendship can overcome loneliness and, I think, often sexual desires may be a proxy for a desire for deep interpersonal communion with others, which can be had and sometimes, in a better way, through friendship. So, friendship can also overcome aloneness.

That’s a very powerful suggestion. Do you have any examples of how friendship can overcome loneliness? Is it just conversation? Is it sitting with another person? Is a Facebook friendship sufficient for overcoming loneliness? In just what way does friendship benefit us so much on that point?

How does friendship really combat loneliness? In many ways. There are different kinds of friendship. Sometimes just being with somebody who cares about us can overcome loneliness. Often, by working together with somebody. This could be working in person on a project. This could be having conversations with fellow hobbyists. This could be having deep intellectual conversations with a colleague. There are many different kinds of friendship, and they all involve different kinds of common activity.

It could be fun, going to the movies. It could be writing a paper together, or a book. All of these let us see somebody else as another self, as somebody that we are united with, as somebody who is, in some way, the presence of Christ for us and makes us not be alone.

There’s pretty staggering numbers in terms of the statistics of the number of Christians of all denominational backgrounds who get divorced. What is the significance of divorce and what does that do to the unified body? What does that do to union?

In the last half‑century, we have seen an enormous rise in divorce, both among non‑Christians as well as almost to an equal degree among Christians in our culture. That creates very tough moral problems. Here, I think one of the things to bear in mind is the analogy between marriage and God’s love.

In the Old Testament, we see God’s people over and over being unfaithful to God, leaving God for other gods, and God remains faithful through all of that. He remains the husband of the bride no matter what happens, and that is very tough.

We’re called to demonstrate faithfulness to somebody we have a covenant relationship with. This is true even when we feel unable to live with them, whether because the other person was unfaithful, or because of insoluble interpersonal problems. It is very difficult to do this, but God’s grace suffices.

Everyone has the desire for a good life. Now, Aristotle brings up, then it comes up in ethics. Everybody agrees that eudaemonia is the highest good. It’s just that we don’t agree about what the content of eudaemonia is. What is the good life?

My view of the good life is very unoriginal. It’s what all the catechisms say. A good life is to know and love God. We know and love God both in Himself, though this is only really adequate in heaven. We know God in creation, and we love Him in creation, and especially in our neighbor. By loving our neighbor, we can love God in very concrete ways. Our neighbor manifests God to us.

The good life is to know and love God. The two are interconnected. Augustine says that we cannot love what we do not know, so the good life will include intellectual effort to know about God as much as one’s place in life, one’s calling allows one to, and then to respond to this knowledge by loving this God that we know about.

How can we obtain the good life?

We can only obtain the good life by the grace of Jesus Christ who lived that we might see how to live and died that we might live His life. I don’t have anything original to add. The Christian tradition contains much advice of various sorts, differently suited for different people.

This life is a life of prayer—individual prayer and communal prayer. It’s a life of joining as a community with others pursuing this life but, ultimately, it is all a gift of grace.

Are there any practices, personally, that you have found that has promoted good life in own your life? What are those practices that have made you more deeply happy, more deeply joyful?

Marriage and having children has made me realize all sorts of vices that I did not realize I had. By highlighting these vices, it sometimes points ways out. There are ways of appearing virtuous simply because one is not being challenged.

Being with others in close proximity, whether through marriage and children or whether through deep friendships, is a way that shows our sinfulness and our need to turn to God for help, and can show us the way out through the example of other people.