📜 Module 10 — The Problem of Evil | Thomas Aquinas Course
Updated: 17 hours ago
Free Course by Everything IFS Academy | Philosophers Series
Help us reach the people who may need this most by sharing this free course with friends, family, colleagues, online communities, social media or on your own website.
🎧 Audio - listen on the go (coming soon)
📜 Module 10 — The Problem of Evil
In a hospital corridor outside the room of a child who is dying of something no one did anything to deserve, the oldest argument against God assembles itself almost on its own. It can be put in a single breath. A real God would possess unlimited power to stop this and perfect goodness to want to, yet it happens anyway. So something has to give: either divine power is limited, His goodness is flawed, or no one is there at all. For a great many people this is not an abstract puzzle but the exact place their faith went to die, and any thinker who takes God seriously has to walk straight into it rather than around it.
Thomas Aquinas does, and his opening move is one of the strangest in the long history of the question. Before he says a single word about why God might permit suffering, he makes a claim about what evil even is, and the claim is that evil, strictly speaking, is not a thing at all. At first it sounds like an evasion, a way of talking around the agony rather than facing it. It turns out to be the foundation of his entire answer. Whether or not it finally satisfies, it is worth understanding from the inside.
A word before walking in. This module is where philosophy stands closest to real grief, and if that ground is fresh in your own life, go gently: take it in pieces, or set it aside for another season. The note at the bottom of every lesson is meant with particular seriousness here.
The Challenge at Full Strength
The argument deserves to be stated at its full force before any reply, which is exactly how Aquinas himself treats it. The traditional account holds three attributes of God at once: omnipotence (unlimited power), omniscience (complete knowledge), and omnibenevolence (perfect goodness). Put those together and a problem follows almost mechanically. A wholly loving being wants to stop suffering wherever possible. Combined with limitless might, no harm would lie beyond its reach, and total awareness means none of it could go unnoticed. So if such a God were real, there should be no evil in the world. Yet suffering saturates it, and not only the moral wickedness people choose; disease and disaster fall constantly on innocents who did nothing to invite them. The conclusion presses hard: God lacks either the strength to stop it or the desire to, or else is not there.
You have likely seen this argument in its most famous costume, the tidy trilemma that circulates online over the name of Epicurus: is God willing to prevent evil but not able, then he is impotent; able but not willing, then malevolent; both able and willing, whence then is evil? Here the story-testing habit you built early in this course earns its keep again, because the attribution wobbles badly under the first question. The lines survive in nothing the philosopher or his school wrote. They reach us through a hostile source, the Christian writer Lactantius, who put the words in his mouth roughly six centuries after his death in order to refute him. The crisp modern wording was later made famous by David Hume quoting "Epicurus's old questions" fifteen centuries later still. Scholars doubt Epicurus framed the reasoning at all, and some trace it to other Greek hands entirely. None of that weakens the case one ounce, since logic never depended on a label. This is simply one more famous quotation wearing a name it never earned, and you now catch these on sight.
However labeled, this is among the oldest and most formidable challenges in all of philosophy, and age has not blunted its edge. Notably, Aquinas does not hide from it. In the great article of the Summa where he asks whether God exists, the very first objection he raises against his own conclusion is this one, stated plainly and without softening, true to the method that required him to give the strongest opposing case the floor before replying. In his view it was the hardest thing anyone could say against belief in God, and his reply begins with what evil is.
Evil as Privation of Good
Aquinas's foundational claim is that evil has no existence of its own; rather than a substance or a positive force operating in its own right, it is a privation, meaning the absence or lack of a good that ought to be present. That last clause is doing careful work, because privation differs from mere absence. A rock is not evil for being unable to see, since sight was never part of what a rock is. Blindness in a creature built for vision, however, is a genuine evil, because something belonging to that creature has gone missing. The measure, in other words, is always what a thing's own nature calls for.
Underneath this sits a piece of his metaphysics, taught in its own lesson elsewhere in this course: everything that exists is good precisely insofar as it has being, a doctrine the tradition calls the convertibility of being and goodness. From that it follows that God, as Creator, brings only goods into existence and never makes evil, because evil is not an item available to be produced. It enters the world instead as a falling-short, a defect or corruption in something that is itself good. Once noticed, the pattern shows up everywhere. Blindness is no dark substance lodged behind the eyes but simply sight gone missing. Darkness amounts to light withheld, and cold does not pour into a room so much as warmth drains out of it. A wound means the body has lost its proper wholeness; rust eats away at sound metal, and a lie robs honest speech of the truth it ought to carry. In every case the evil is parasitic, able to survive only by feeding on something good. Strip that goodness away entirely, and what remains would not be pure evil but simply nothing at all.
Privation Does Not Mean Illusion
Stop here for the misunderstanding that ruins this doctrine for half the people who meet it. Hearing "evil is an absence," many conclude Aquinas is saying evil is not real, that suffering is somehow imaginary, a trick of perspective that enlightenment dissolves. He is saying nothing of the kind, and the difference is everything. A missing rung in a ladder is an absence, yet it will break your leg. Blindness has no positive existence and still leaves a person unable to see, just as the hole in a boat's hull, precisely a nothing, sends the whole vessel to the bottom. Absences with an ought attached are fully real in their effects, which is why the privation account is no cousin of those systems that call evil an illusion to be seen through. Aquinas's claim concerns strictly what kind of reality evil has: rather than a created something with its own existence, it is a genuine lack, a wound in the fabric of good things. The child in the corridor is truly dying. Nothing in this doctrine whispers otherwise, and any reading of it that starts to sound like denial has left Aquinas behind.
This reframing settles one question cleanly. The charge that God must have authored evil loses its footing, because on this account there was never an evil thing there to author, and the same logic explains why evil always clings to good and never stands alone. What the doctrine has not yet done, as Aquinas well knows, is explain why God permits the privations to happen, nor has it touched in any way the felt weight of suffering. Those are separate matters, and naming what evil is leaves them untouched.
Why God Permits It
The next question is why a good and powerful God allows the privations at all, and Aquinas handles two kinds of evil differently.
Moral Evil. A great deal of evil flows from the free choices of creatures, and here Aquinas points to the value of freedom itself, a line of response modern philosophy calls the free will defense. God made beings genuinely free, and that liberty is a real and great good, yet a will incapable of ever choosing wrongly would not be free at all. On his account God never causes the evil choice; the wrong turn is itself a privation, a failure of the will to hold to what reason and goodness call for. God brings the free creature into existence and then permits the misuse that the gift leaves open. Ruling out moral evil entirely would have meant withholding freedom, and with it everything such liberty allows.
Natural Evil. The suffering that comes from disease, disaster, and the way living things exist at one another's expense is harder, and Aquinas leans on the good of an ordered world of real natures. In a universe where things have authentic characters and act according to them, certain goods come bound up with certain losses. The fire that warms can also burn, just as one creature's survival may demand another's death. God, on this view, wills the good of the whole ordered creation while permitting the particular privations that interacting beings inevitably involve, never desiring evil for its own sake as an end but allowing it as tied to goods that are intended.
Holding both together is a principle Aquinas takes from Augustine, and if you did the reading when this course sent you to the article on God's existence, you have already met it in his own reply to the evil objection: that God, being supremely good, would never permit any evil at all unless he were able and willing to draw some greater benefit even out of it. So on this account God's relation to evil is always permission rather than authorship, with that allowance bent toward a good lying beyond the harm. This whole effort, the attempt to square divine goodness with the reality of evil, has a name, theodicy, and like every attempt of its kind it is offered as a defense rather than a proof.
What the Answer Costs and Keeps
Honesty requires saying plainly what the answer leaves undone. The privation account is an elegant piece of metaphysics, yet it makes no one's suffering hurt one degree less, and it was never built to. A serious objection stands right here. To someone holding a dying child, the sentence "evil is only the privation of a good" can sound cold, abstract, even insulting, like a clever move that defines the agony out of existence instead of facing it. That reaction points at something true rather than being a misunderstanding in need of correction. A reframing of what evil is neither answers the cry of why nor offers any consolation.
The deeper limit is that even if the privation account is granted, the hardest form of the question survives it: why so much of it, why it falls on the innocent, and why these particular horrors, when the good supposedly drawn from them is so often impossible to see. Serious philosophers, along with countless people who have suffered far past the reach of argument, find no theodicy fully satisfying, and the problem of evil remains, by broad agreement, the single strongest case against belief in God. Aquinas's answer does not pretend to close it.
What the answer keeps, for those who find it persuasive, is still real. The charge that God created evil is blocked, since on this account there was nothing there to create, and the strange clinging of evil to good, its inability to stand alone, finally gets an explanation. Meanwhile the coherence of an all-good creator is preserved without softening one fact about what the world actually is. Aquinas himself drew a line worth holding onto. What evil is, and how it can exist alongside God, can be met with reasoning. The lived weight of a particular grief belongs to a different order entirely, and he never offered his philosophy as a cure for that. Within his own framework the final response to suffering was a hope rather than a syllogism: that the good for which God permits evil is real, and will one day be seen for what it was. Whether that hope can bear the weight placed on it is, in the end, the question each person is left holding.
The Missing-Good Move
Now for something unexpected: the privation doctrine, whatever you conclude about the theodicy, contains one of the most practical thinking tools in this whole course. If everything bad is a missing good, then any "this is awful" can be interrogated into a specification, which is something you can actually work with. Vague badness paralyzes; a named absence points somewhere. Here is the move, in five steps.
Catch the reaction. Something is bad, wrong, awful, off. Instead of circling in the badness, stop and ask the privation question: which good, one that ought to be present here, is missing? The aim is to locate an absence rather than list everything you hate about the situation.
Name it precisely, and apply the ought-test from this lesson as you do. A rock is not deprived of sight, so a lack only counts as a privation when the good belonged there to begin with. Which good does this situation, by its nature, owe and fail to deliver? Push past the first vague answer to the exact one. "My job is terrible" is weather. "Recognition for finished work is absent, and so is a schedule I can plan a life around" is a map. When Connie finally ran this on a year of Sunday dread, those were her two absences, and she was startled to find the whole misery was, on inspection, exactly a pair of holes.
Sort each named absence by who or what could restore it: you, someone else if asked, time alone, or nothing at all. This one step is where the move pays. Connie's schedule problem landed in the ask-someone column, which converted a year of dread into one Tuesday conversation. Her recognition issue resisted easy placement, and even that was a gain, because a clarified decision beats a fog.
Act or accept accordingly. A restorable absence becomes a concrete task, while an unrestorable one turns into a clearly named loss, and losses with names, unlike vague miseries, can actually be grieved and carried. The move never promises the good back; what it guarantees is that you will know what you are dealing with.
Note what the bad is riding on. Privation is parasitic, so every wrong marks a good still standing under it: rust means there is metal, betrayal implies a bond worth betraying, and disappointment reveals something that was rightly hoped for. This is not a gratitude exercise. It is structural seeing, and it changes how a harm appears without denying one ounce of its badness.
Philosopher's Practice: The Privation Ledger
Three parts, sized honestly, with one of them entirely at your discretion.
#1. Run the move small. Open a notebook page titled "The Privation Ledger" and, over the coming week, take three ordinary irritations (the commute, a recurring argument, whatever always grates) and run the Missing-Good Move on each in writing: how the bad feels, which good is precisely missing, where it sorts, and the resulting line, whether task or acknowledged loss. Watch what the naming does. Most people find at least one longstanding complaint dissolve into a fifteen-minute action it had been hiding, and another reveal itself as a loss they had never actually named, which is its own strange relief.
#2. Go deeper only if you choose. The move works on real losses too, and some students take it there: naming, with full precision, the good that a genuine grief is the absence of. Many find the naming honors what was lost, steadies them, and turns a shapeless ache into something that can be carried deliberately. But this step is offered, never assigned. If the ground is raw, leave this part unwritten, or bring it to a person rather than a page. A philosophy course is a place to think about suffering; it is not the place to be alone with it, and the resources in the footer below are there for exactly that line.
#3. Write the Corridor Page. Finish with your judgment on the whole module, in two short columns and a sentence. Costs: what, in your own words, the privation answer and the theodicy fail to reach. Keeps: what they genuinely secure, again in your own phrasing. Then the verdict line: for me, standing in that corridor, the answer holds, falls short, or holds in part, because. Beneath it, in the habit that is now simply how you think, add the strongest case you can make for the side you did not take. Date the page and know that whichever verdict you wrote, you stand in serious company, believers and unbelievers both, and that writing an honest conclusion on the hardest question in philosophy is not a small thing to have done this week.
Disclaimer: Everything IFS Academy is an independent educational platform and is not affiliated with, endorsed by, or connected to the IFS Institute. While we strive for accuracy, errors can occur, and users are encouraged to cross-reference critical information. These courses present the ideas of historical philosophers for educational and self-reflection purposes only. They describe what these thinkers taught and argued and do not constitute an endorsement of any philosophical position, nor do they constitute religious instruction or professional advice of any kind. They do not constitute therapy, mental health treatment, clinical training, or crisis support, and they should not be used as a substitute for professional mental health care.
Crisis Support:🚨 If you are experiencing a mental health crisis, feel unsafe, feel at risk of harming yourself or someone else, or feel too overwhelmed to safely use self-directed practices, please pause this material and reach out for immediate support. Contact a licensed mental health professional, call or text 988 in the U.S. or Canada, or use your local emergency or crisis resources.
Comments