Matt Fradd
Spirituality/Belief • Books • Writing
What I Should Have Said to Dennis Prager about The Sin of Onan
April 25, 2023
post photo preview

In my recent conversation with Dennis Prager, the subject of masturbation came up. 

Prager said that since masturbation is nowhere condemned in the Old or New Testaments, this serves as evidence that masturbation is not a sin. 

This is what is called an argument from silence, where a conclusion is based upon silence or lack of evidence. Such arguments aren’t always illegitimate, but they are notoriously weak and inconclusive. The Bible also does not condemn insider trading and chattel slavery, for example, but Prager would condemn these as sins.

Prager also responded preemptively to something he suspected I might bring up—the sin of Onan:

Judah took a wife for Er his firstborn, and her name was Tamar. But Er, Judah’s first-born, was wicked in the sight of the Lord; and the Lord slew him. 

Then Judah said to Onan, “Go in to your brother’s wife, and perform the duty of a brother-in-law to her, and raise up offspring for your brother.” But Onan knew that the offspring would not be his; so when he went in to his brother’s wife he spilled the semen on the ground, lest he should give offspring to his brother. And what he did was displeasing in the sight of the Lord, and he slew him also (Gen. 38:6-10).

This passage involves the Hebrew custom of levirate marriage, according to which, if a man died childless, it was his brother’s duty to marry the widow and father children who would be legally regarded as sons of the dead man. It is called levirate marriage since levir is the Latin term for brother-in-law, and the woman’s brother-in-law is the biological father of the children.

Onan did not wish to father children for his dead brother, but he did want to have sexual pleasure from the widow, so he practiced coitus interruptus to avoid inseminating her—allowing him the pleasure of sex with the woman but preventing him from fathering children for his brother.

This passage has been used by many Christians as a prooftext against deliberately rendering the sexual act infertile, which includes masturbation.

However, Prager made the case that Onan was punished not for “spilling his seed” but for violating the levirate marriage custom.

At the time of my discussion with Prager, I wasn’t equipped to respond to this objection in the heat of the moment, and so I addressed his objection from a natural law perspective. Namely, we can know by reason what sex is for (union and procreation), and to deliberately thwart the end of sex is a perversion. 

While it can be tricky to discern the nuances of what was in the mind of a biblical author writing 3,000 years ago, if I could engage Prager on this again, I would make these points:

 

1. Prager Is at Odds with Other Jews

Prager is at odds with the respected Jewish commentary, Bereishis: Genesis which states:

[Onan] misused the organs God gave him for propagating the race to unnaturally satisfy his own lust, and he was therefore deserving of death (5:1677).

 

2. The Penalty Is Far Less Severe in the Mosaic law

If Prager was correct and Onan was struck dead by God for refusing to give offspring to his deceased brother’s wife, why isn’t the death penalty applied to other cases where a man refuses to fulfill the duty of a brother-in-law?  The penalty announced by the Mosaic law isn’t death but merely public humiliation. If a man refuses to perform the duty, then:

His brother’s wife shall go up to him in the presence of the elders and pull his sandal off his foot and spit in his face. And she shall answer and say, “So shall it be done to the man who does not build up his brother’s house.” And the name of his house shall be called in Israel, “The house of him who had his sandal pulled off” (Deut. 25:9-10). 

The fact that the Mosaic law required public humiliation for failing to fulfill the responsibility—but Onan was put to death—indicates that Onan was guilty of more than just failing to fulfill the responsibility. There was something immoral about the sexual acts that he performed with the woman. 

Thus, the text says that “what he did [i.e., the sex acts with coitus interruptus] was displeasing in the sight of the Lord.” It does not say “what he did not do [i.e., give children to his brother]” was what earned him death. The latter failure would only have warranted public humiliation according to God’s law through Moses. The way the text presents matters, it’s what Onan did do, not what he didn’t do, that caused his death.

 

3. The Use of Graphic Language

Hebrew contains several ways of referring to the sexual act—to “know,” to “go in to,” and to “lie with.” The first of these is the most decorous and normally refers to lawful, wholesome sexuality (e.g., “Adam knew Eve his wife,” Gen. 4:1). The latter two are more blunt and can refer to both lawful and unlawful sex.

In Genesis 38, we go beyond these simple descriptions, and we are told the precise details of what Onan did: “When he went in to his brother’s wife he spilled the semen on the ground.” This unexpected intrusion of the graphic details of what Onan did calls attention to the specific thing that he did wrong. As Fr. Brian Harrison notes:

If the inspired author, while knowing the same historical facts, had evaluated them in the way most modern exegetes would have us believe he did (with moral indifference toward Onan’s contraceptive act as such), we would expect quite different wording. “Spilling the seed,” being irrelevant to the author’s interest and purpose on that hypothesis, would not even have been mentioned. Instead, we would expect to be faced with an account stating more discreetly that, even though Onan took Tamar legally as his wife, he refused to allow her to conceive, so that God slew him for his “hardness of heart,” his pride, or perhaps his avarice (in wanting his brother’s property to pass to himself and his own sons) (The Real Sin of Onan).

 

4. Natural Law

We also should consider what happened from the perspective of natural law—that is, what a reasonable person would conclude based on human nature.

One way of applying this to the current situation is to simply ask, “What are human genitals supposed to do? What’s their function?”

The answer is obvious. They have two functions: eliminating waste (urine) and facilitating reproduction (directly, through the transmission of semen, and indirectly, through uniting the spouses). These are their obvious, proper uses.

Therefore, if you’re doing something else with your genitals—or if you deliberately keep them from fulfilling their proper uses, as Onan did—then you are misusing them by definition.

 

5. Protestants Should Agree With Catholics

Only for Supporters
To read the rest of this article and access other paid content, you must be a supporter
26
What else you may like…
Videos
Podcasts
Posts
Articles
The Tide is Turning - Fr. Gregory Pine, O.P.

I just got back from five weeks of preaching and travels which took me to Australia and Italy. I have been super encouraged by what I have seen in these days, especially by the interest in the faith and the desire on the part of young people to follow the Lord Jesus. It might just be that the tide of secularization is turning in the developed world.

00:19:48
Further Thoughts on the TLM - Fr. Gregory Pine, O.P.

With recent announcements in Charlotte and Detroit, it feels like old wounds are getting re-opened. This video provides a couple of principles and arguments that can help think through and pray though liturgical life in 2025.

00:25:05
Boundaries in Conversation - Fr. Gregory Pine, O.P.

Hello! Ever unsure of where to spend your time? I was thinking about this recently apropos of responding to emails and engaging in conversations. I'm not sure that I've come up with tight conclusions yet, but I have at least begun to formulate some principles. I hope that it's helpful for you! Cheers!

00:24:04
Simple NEW Lofi Song

Working on an entire album of lofi music. Here's one of those songs. Album should drop next week. THEN, a couple of weeks after that we hope to have our 24/7 stream up and running.

Simple NEW Lofi Song
December 01, 2022
Day 5 of Advent

THE ERROR OF ARIUS ABOUT THE INCARNATION

In their eagerness to proclaim the unity of God and man in Christ, some heretics went to the opposite extreme and taught that not only was there one person, but also a single nature, in God and man. This error took its rise from Arius. To defend his position that those scriptural passages where Christ is represented as being inferior to the Father, must refer to the Son of God Himself, regarded in His assuming nature, Arius taught that in Christ there is no other soul than the Word of God who, he maintained, took the place of the soul in Christ’s body. Thus when Christ says, in John 14:28, “The Father is greater than I,” or when He is introduced as praying or as being sad, such matters are to be referred to the very nature of the Son of God. If this were so, the union of God’s Son with man would be effected not only in the person, but also in the nature. For, as we know, the unity of human nature arises from the union of soul and body.

The...

Day 5 of Advent
November 27, 2022
Day 1 of Advent

RESTORATION OF MAN BY GOD THROUGH THE INCARNATION

We indicated above that the reparation of human nature could not be effected either by Adam or by any other purely human being. For no individual man ever occupied a position of pre-eminence over the whole of nature; nor can any mere man be the cause of grace. The same reasoning shows that not even an angel could be the author of man’s restoration. An angel cannot be the cause of grace, just as he cannot be man’s recompense with regard to the ultimate perfection of beatitude, to which man was to be recalled. In this matter of beatitude angels and men are on a footing of equality. Nothing remains, therefore, but that such restoration could be effected by God alone.

But if God had decided to restore man solely by an act of His will and power, the order of divine justice would not have been observed. justice demands satisfaction for sin. But God cannot render satisfaction, just as He cannot merit. Such a service pertains to one who ...

Day 1 of Advent

For the feast day of St. John Vianney, I happened to be in Iowa and went to Mass. The priest gave a great homily that included this off-the-beaten-path bit of Church history that really stuck with me. He explained why it took nearly 1,900 years for the Church to officially name a patron saint for parish priests. Until then, most of the spiritual heavyweights were thought to be religious—monks, friars, that sort of thing. Bishops typically came from religious orders. Parish priests, the diocesan guys, were often lumped in with the laity when it came to spiritual rank… at least practically speaking. Families had a lot of children and it was pretty common for everyone to have a priest in their family.

But St. John Vianney changed that. His life of heroic virtue and tireless devotion to his little parish made it clear that diocesan priests carried their own spiritual weight. His witness shifted the perception of the priesthood itself.St. John Vianney used to spend up to 18 hours a day in the ...

post photo preview

To Matt and all fellow Australians here, happy feast of St Mary of the Cross, Australia's first (and only!) saint. I know it's not a very exciting image, but it's real and I couldn't find one of her riding a kangaroo.

post photo preview
August 05, 2025

Cody Hayes story below inspired this post.

On Sunday my wife and I baptized my two children, glory to God.

They should have been baptized when they were born, but long story short I had fallen away from Catholicism and spent many years living in sin… three years ago the Holy Spirit opened my eyes and I knew I had to come to God and that I needed to baptize my children as part of what god was asking me to do for my family and household.

It’s been a long journey back, with many trials and graces. I would like to say that I immediately baptized the kids. But in truth it was hard. But my wife and I persevered and a few months ago we decided we would delay no longer. We began meeting with our priest, and when we scheduled the baptism I felt an extraordinary gift of peace.

Well, someone did not want us to go through with it and was throwing a bit of a fit. The week leading up to the baptism was filled with nonsense around the house. There was just a heavy angry air around the house, you could ...

post photo preview
A Practical Method For Spiritual Warfare
 
In this article, I want to suggest a powerful, practical method for spiritual warfare—one that I believe will be a game-changer in your everyday life. We'll explore how consistently announcing what is true and renouncing what is false can become a potent weapon, helping you navigate the unseen battles that often manifest as struggles in our thoughts and emotions.
 
At the Catholic Easter Vigil Mass, there is a significant moment where the congregation renews their Baptismal Promises.

In essence, the priest leads the faithful to announce what is true and to renounce what is false.

For the purposes of this article we’ll begin with the questions that invite annunciations. He asks:

"Do you believe in God, the Father almighty, Creator of heaven and earth?"

"Do you believe in Jesus Christ, his only Son, our Lord, who was born of the Virgin Mary, suffered death and was buried, rose again from the dead and is seated at the right hand of the Father?"

"Do you believe in the Holy Spirit, the holy Catholic Church, the communion of saints, the forgiveness of sins, the resurrection of the body, and life everlasting?"

In responding “I do” to these questions, we are in a very real sense aligning ourselves with reality. While emotions may be present, they don’t need to be. Simply stating our agreement with the way things are is enough.

Prior to the above questions are a series of questions which invite renunciation:

"Do you renounce sin, so as to live in the freedom of the children of God?"

"Do you renounce the lure of evil, so that sin may have no mastery over you?"

"Do you renounce Satan, the author and prince of sin?"

In responding “I do” to these questions, we are renouncing, repudiating, what is false.

To those who may attend Holy Mass once or twice a year they may be surprised to discover just how seriously the Church takes the reality of the Devil and spiritual warfare. But anyone somewhat familiar with the Scriptures and the consistent teaching of the Church would not be. Here I could dump a multitude of Scriptural verses proving my point, but one will suffice. From the first letter of St. Peter:

"Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour. Resist him, firm in your faith, knowing that the same kinds of suffering are being experienced by your brotherhood throughout the world."

And now for the main point of this article: Just as it is beneficial to regularly align ourselves with what is true (say through an act of faith), it is also beneficial to regularly repudiate, and disassociate with, what is false.

And given that our lives are situated squarely within a world at war. A world which “lies in the power of the evil one.” in which demonic forces are seeking to blind us to the things of God (2 Cor. 4:4). This is something we are going to be needing to do in one form or another on a daily basis. Multiple times a day.

Let me offer a personal anecdote that will illustrate this. I was about to interview someone on a topic that I knew would get blowback from the Demonic realm. I was going on a walk praying my rosary before my guest arrived. While I was walking I slowly became aware of a sort of oppressive force. I felt sad and restricted, somehow. Anxious. I’m not sure how long I was feeling that way, but at any rate I didn’t become conscious of it until that moment. I stopped walking and tried to sum up what I was experiencing in a word. It clicked. intimidation. That’s was it. I felt intimidated. And so I said the following prayer:

Only for Supporters
To read the rest of this article and access other paid content, you must be a supporter
Read full Article
post photo preview
Life is very, very simple, actually.

There is a lot going on. We are confused about many things. Embarrassed that we are confused. Pretend not to be. Have a few soundbites we can rely on when the conversation turns to Trump or the state of the Church or what is going on in Israel and Gaza or the AI revolution. We hope they don’t press us because we know enough to answer two or three questions before they will hit bedrock and we will have nothing.

All of this can lead us to believe the lie that life is complicated. And since we cannot figure it out, we should either quit, or numb, or pretend, or run ourselves ragged trying to understand everything we think we should understand.

And yet life is simple. Very, very simple. There is very little to figure out.

Love what is good. Hate what is evil. But how? When I have willingly habituated myself to do the opposite. Pray. Repent. Keep turning away from distractions. Don’t hate yourself for failing. Hope in the good God who is better than you think He is. Who cares for you more than you think He does.

What are your duties? Do them with joy and attention. Don’t hate yourself when you fail at this. Pray. Repent. Have a sense of humor about your littleness. You are incredibly loved after all, remember?

Turn away from what is useless and petty and vulgar and think about what is excellent.

Say “Your will be done” 100 times a day, especially when things are bad or seem meaningless. Your headache. Your bad night sleep. The house you can’t seem to get around to tidying.

Be patient and gentle with stupid people who can’t seem to make themselves love or want to love what is good, yourself first and foremost.

Jesus, help me want to want to love you. Help me want to want to hate anything opposed to you or your kingdom.

Seek first the kingdom of God and his righteousness, and all these things will be added to you.
Read full Article
post photo preview
Is Knowledge Possible (No ... And Yes)

I want to begin by admitting that I’m an amateur when it comes to epistemology. I do have a master’s degree in philosophy, but epistemology wasn’t my area of focus. Some of you reading this will know more about the subject than I do. And to be honest, I’m a little nervous about the comments. There’s a good chance that if you engage with what I’m about to say in any real depth, I won’t understand you and it will be my fault that I don’t.

Okay, with that admission out of the way…

 

We've long assumed that knowledge requires three criteria: (1) belief, (2) truth, and (3) justification. In other words, to know something is to believe it, for it to be true, and to have good reason for believing it. That’s the classical definition: justified true belief (JTB).

And just real quick, if you’re wondering why knowledge can’t be defined by just the first two criteria, it’s because believing something that happens to be true is more like getting lucky than knowledge. Imagine I say it’s raining in Adelaide, but I have no reason for thinking so. I didn’t check my weather app or ask anyone who lives there. If it turns out that it is raining, I was right, but only by chance. That’s not knowledge. To genuinely know something, you need more than belief and truth, you need a reason for thinking it’s true. You need justification.

Okay …

Along Comes Gettier

Now, for a long time, this three-part definition held up well. But then, in 1963, Edmund Gettier came along and broke everything in three pages. You can read that paper here.

Gettier presented scenarios where someone has a belief that is both true and justified, yet we still hesitate to call it knowledge. Why? Because the belief turns out to be true by accident.

One of the most well-known examples (though not from Gettier himself but often used to illustrate his point) is the case of the stopped clock. A man glances at a clock that has stopped working, sees that it says 2:00, and forms the belief that it is 2:00. And it just so happens to be 2:00. His belief is true. He used a normally reliable method, checking the time on a clock. And yet, the method failed. The belief was correct purely by coincidence.

Can We Save “Knowledge”

Now, some have tried to save the classical definition by saying, “Well, that wasn’t really justified. The clock was broken, so the belief was faulty from the start.” But that kind of move just shifts the problem. If we start redefining justification every time we hit a weird case, we risk making it so strict that it no longer resembles what anyone would call a “justified belief.”

Others, like Alvin Goldman, proposed ditching the concept of justification entirely. Maybe knowledge isn’t about having reasons, but about using processes that generally lead to truth. This is called reliabilism: if your belief comes from a trustworthy process (like vision, memory, or scientific inference) it counts as knowledge.

But again, the clock case poses a problem. Even if the process is usually reliable, it clearly failed here. So are we back to calling this knowledge, even though it was true by luck?

Still others have suggested that knowledge is less about having the right reasons or processes, and more about the person doing the knowing. This is what’s known as virtue epistemology: the idea that knowledge is a kind of intellectual success rooted in intellectual virtue: careful thinking, honesty, openness to evidence. On this view, knowing isn’t about checking boxes; it’s about doing something well. Like an archer hitting the bullseyes, not by accident, but through skill.

That’s compelling. But even here, questions linger. How do we measure intellectual virtue? And isn’t it still possible to do everything right and end up wrong—or to be wrong for the right reasons and still, somehow, stumble into truth?

An (Initially) Unsettling Realization

Which brings me to a more unsettling thought.

If a belief like “it’s 2:00” can be true, feel justified, come from a reliable process, and still be the product of a broken clock—what else might we be getting wrong without realizing it? Maybe the deeper problem is that we can always be deceived. Even our best faculties (sight, memory, reason etc.) can betray us. And if that’s the case, maybe knowledge (at least in the strong, philosophical sense) is impossible. Or if not impossible, impossible to know if and when you have it.

David Hume once said, “A wise man proportions his belief to the evidence.” That strikes me as a sane and honest approach. The question isn’t whether I can be absolutely certain about what I believe, but whether I have good reasons for believing it—and whether I’m open to changing my mind if those reasons fall apart.

Some might find it unsettling—even scandalous—that we can’t achieve a God’s-eye view of the world. But honestly, what’s strange isn’t that we can’t see things with perfect clarity. It’s that we ever thought we should.

Maybe that’s why I find myself leaning toward fallibilism—the view that we can still know things, even while admitting we might be wrong. That kind of knowledge isn’t rigid or absolute, but humble and revisable. And that, to me, feels much closer to the way real life works.

So no, I’m not sure we need to cling too tightly to the word knowledge, at least not in the abstract, capital-K sense. What matters more is the posture we take toward the truth. That we pursue it carefully, honestly, and with a readiness to revise our beliefs when the evidence calls for it.

At least, that’s what I think I know.

 
Read full Article
See More
Available on mobile and TV devices
google store google store app store app store
google store google store app tv store app tv store amazon store amazon store roku store roku store
Powered by Locals