Imputed Sin: Why Thomas Aquinas’s Angels Matter
I’ve spoken on this topic many times before, and those who know me have heard me reference it often. It was even the subject of one of my major papers back in seminary. Recently, as I was reading Aquinas, this old discussion came back to mind. So I thought I’d revisit it here and polish up my thoughts a bit.
The Problem
Many people today, especially in our postmodern world, struggle with the concept of imputed sin. This includes some from the Eastern Orthodox tradition, who often find the idea of being held accountable for Adam’s sin deeply unsettling. Before we dive in, let’s clarify the three types of sin theologians talk about: personal sin, inherited sin, and imputed sin.
1. Personal sin is our own wrongdoing. You can’t really argue with this, can you? If so, we need to talk.
“If we say we have no sin, we deceive ourselves, and the truth is not in us…” (1 John 1:8–10)
2. Inherited sin is the condition we’re born into—a kind of spiritual inheritance from Adam. It is the “sin virus,” and we all have it. So far so good? It’s why you feel driven to sin just like you’re driven to things that aren’t good for you.
“Can the Ethiopian change his skin or the leopard his spots? Then also you can do good who are accustomed to do evil.” (Jeremiah 13:23, ESV)
3. Imputed sin is the judicial reckoning of Adam’s sin to all humanity. This is the divine gavel being struck the moment you were conceived. Picture all the leaders of Krypton at the beginning of Superman (1978 version). “Guilty” is what is said about you concerning Adam’s sin. If you die without intervention, you have no hope of ever being with God. It is the condemnation of the entire human race, in and with Adam.
“Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned.” (Romans 5:12)
We can grasp personal sin easily enough. Inherited sin, though still hated by some, is often understood as a kind of spiritual “virus” passed down from Adam. But imputed sin? Really? This is the one many reject outright as unfair. “Why,” they ask, “am I held guilty for the sin of another?”
Paul addresses this directly:
“Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men.” (Romans 5:18)
Aquinas and Angels
Here we are! Let me introduce you to my friend, Thomas Aquinas. We call him the “Dumb Ox.” (Though, don’t say that to his face… He doesn’t like it.) While being saddled with that name in his version of grade school by the other students, he turned out to be one of the 13th century’s greatest thinkers. What am I saying? He’s one of the greatest thinkers of all time (though, don’t tell Martin Luther that—he didn’t think much of Aquinas’s love for Aristotle).
Specifically, we’re going to look at Aquinas’s view of angels. Aquinas taught that each angel is its own species. Unlike humans, angels don’t share a common nature. Each angel stands alone, morally and ontologically. This means angels cannot be redeemed in the same way humans can. For Christ to redeem angels, He would have to become each individual angel—which is metaphysically impossible.
“If, therefore, the angels be not composed of matter and form… it follows that it is impossible for two angels to be of one species.” (Summa Theologica, I, Q. 50, Art. 4)
The Implications for Humanity
What does this mean for us? It highlights the importance of our shared human nature. We are one species. Because humanity is united in Adam, Adam’s sin can be imputed to all of us. This shared nature, which makes imputed sin possible, is also what allows Christ’s righteousness to be imputed to us. The same principle that some reject as unfair is the very principle that makes universal redemption possible.
The Crucial Turn
Here’s the crucial turn: If God had decided not to connect us in this way—if He had said, “I’ll let each human stand alone like an angel”—then while we might avoid imputed sin, we would also lose the possibility of imputed righteousness. Christ’s redemptive act relies on this shared human nature. Without it, salvation would be purely individualistic, and the universal scope of redemption would be lost.
The Graciousness of Imputed Sin
Now here’s the twist: the imputation of Adam’s sin might be one of the most gracious acts in God’s redemptive plan. Why? Because it sets the stage for the imputation of Christ’s righteousness. The very mechanism that allows sin to be imputed to us also allows righteousness to be imputed to us. Without the first, the second wouldn’t be possible.
We know from Hebrews 2:16:
“For surely it is not angels that he helps, but he helps the offspring of Abraham.”
This tells us there is no savior for angels. If each angel is its own species, as Aquinas suggests, then God could not redeem them collectively; they would lack a representative. Christ would have to become each individual angel to redeem them—and He didn’t.
Conclusion
But He did become one of us. And that’s the difference.
One thing we do know is that He could redeem us because we are connected to that which fell in the garden. The evil that Satan intended became the foundation for God’s redemptive plan. Through Adam, sin entered the world, but through Christ, redemption and righteousness are made available to all.
We don’t know everything about angels. But we do know this: there is a Savior for us, and not for them. And that’s not a mark of injustice—it’s the mark of breathtaking grace.
