The Problem of Evil

The Problem of Evil is not a single problem, but rather a family of arguments for the non-existence of God. In its least ambitious form, the argument cites the evil and suffering we find in the world as compelling evidence that the world is not under the control of an omnipotent Deity, while allowing that the evidence is not decisive. In its most ambitious form, it presents the fact of evil as conclusive proof that God does not exist. Here I present a version of this ambitious argument. I leave it up to you to construct and assess some more moderate version of the case.

Some preliminary definitions



The argument operates with the traditional philosophical conception of God, according to which God is supposed to be an omnipotent, omniscient and omnibenevolent being; and before we begin, we need to say a word about omnipotence.

The claim that God is omnipotent can be understood in three ways. Our casual formulation has been to say that an omnipotent God is a god who can do absolutely anything. We might take this literally:

(A) God's omnipotence consists in the power to bring about absolutely any state of affairs.

On this view, not only is it in God's power to create the physical universe ex nihilo; it is in God's power to bring it about that 2+2=5, or that some triangles have four sides, or that a single thing is simultaneously red and and colorless through and through.

Alternatively, we might take the claim as follows:

(B) God's omnipotence consists in the power to bring about absolutely any logically possible state of affairs.

On this view, it is in God's power to create unicorns and centaurs, along with horses and goats, since there is no contradiction or incoherence in the supposition that these things exist. But it need not be in his power to bring it about that 2+2=5 or that something is both red and colorless through and through.

Finally (and least plausibly) we might take the claim as a claim about physical possibility:

(C) God's omnipotence consists in the power to bring about any physically possible state of affairs, i.e., any state of affairs that is consistent with the laws of nature.

On this view, God could easily have brought it about that the solar system contains an extra planet, since (so far as we know) this would involve no violation of any natural law. But it would not be in his power to cause the sun to earth to reverse direction in its orbit around the sun, since that would involve a violation of the basic laws of motion.

For our purposes, either (A) or (B) would do as an interpretation of the doctrine of divine omniscience. (B) is more orthodox, I believe, and I will proceed with this interpretation in mind. The important point is to appreciate the difference between logical possibility and physical possibility or compatibility with the laws of nature.


The argument as it is traditionally presented operates with a notion of "evil" that may strike some of you as obscure or misguided. For our purposes, however, it will suffice to consider only a very narrow class of evils.

When I speak of an "evil" I shall mean a state of affairs that involves the suffering of an innocent human being. I am not at this point asserting that there are any innocent human beings, or that there is such a thing as human suffering. Nor am I asserting that the suffering of animals and trees (not mention the suffering of guilty human beings) is not morally relevant. I am simply offering a stipulative definition of a somewhat technical term. It is not unrelated to our ordinary understanding of the word; but it is more precise, and we shall see that precision is important in this area.


We distinguish between two kinds of evil: By a natural evil I mean a state of affairs involving the suffering of an innocent human being that is not the direct consequence of any human action. A human evil, by contrast, is an episode of suffering caused by human activity. Intuitively, the human evils are the evils we inflict upon one another; the natural evils are the evils we suffer at the hands of nature, independently of our own collective agency. The problem of evil as it is standardly presented concerns both sorts of evil. But the strongest version of the argument focuses on natural evil alone; and that is the version we shall discuss.


Let us say that an evil is necessary if it is a logically necessary condition for the realization of some great and important good. I cannot give a convincing example here, but I can give you a sense of what I have in mind by considering some imperfect approximations to the idea. When a doctor gives you a shot in order to vaccinate you against a disease, the momentary pain you suffer is an evil in our technical sense of the term (assuming you are innocent, of course). But it is clearly justified by the future good it makes possible. Given our technological limitations, the pain is in a sense a necessary evil: it is a bit of suffering without which a greater good -- namely freedom from disease -- would not be possible. Now the pain of vaccination is not a necessary evil in any absolute sense. A painful shot may be the only way for us to prevent the disease at this point in our history: but it is certainly logically possible that there should be a painless "magic bullet" that confers complete immunity at no cost whatsoever. So the painful shot would not be an example of an absolutely necessary evil. On the other hand, if it could be shown that some great good could not possibly be achieved without some human suffering, then we should say that such suffering is to that extent necessary. Much more could be said by way of explanation here. But I hope the notion will be clear enough for our purposes in what follows.


Our version of the argument proceeds as follows:

(1) If God exists, God is a perfectly benevolent omnipotent being. (By definition)

(2) A perfectly benevolent being would prevent any unnecessary natural evil if he could. (Premise)

(3) An omnipotent being could prevent all unnecessary natural evil. (Premise)

(4) Therefore, if there were a God, there would be no unnecessary natural evil. (From 1, 2, and 3)

(5) But there is unnecessary natural evil. (Premise derived from experience)

(6) Therefore, there is no God. (From 4 and 5)

The argument is valid. The only real question is whether we have reason to accept the premises.

The first premise is a simple consequence of the definition of "God" that we have agreed to accept; so there is no room to quibble at this step.

Premise (3) seems rather hard to deny. Omnipotence is (at least) the power to bring about anything that is logically possible. But it's hard to think of a case of unnecessary human suffering the prevention of which would imply a contradiction or some other sort of logical impossibility. The paradigm cases will be episodes of human suffering in the wake of floods, earthquakes, plagues and other natural disasters. And it would seem to be a straightforward consequence of our understanding of divine omnipotence that an omnipotent deity could easily prevent this sort of suffering if he chose to do so.

This leaves the theist with two plausible lines of response: He can deny premise (2) and maintain that divine benevolence is compatible with the existence of unnecessary natural evil, or he can deny the existence of such evil altogether. Let's consider these options in reverse order:

The Case for Premise 5

The claim that there exists unnecessary natural evil is really four claims in one:

It is perverse to deny (5.1). It has sometimes been maintained (e.g., by Mary Baker Eddy) that bodily pain is entirely unreal because the body itself is an illusion. Now there are interesting philosophical questions about whether there could be an illusion of pain. (If my arm has been amputated, I main have the illusory sense that I have a pain in my arm; but the illusion is a mistake about the location of my pain. The pain itself is perfectly real.) But even if we grant that there is nothing self-contradictory in the suggestion that some apparent pains is illusory, still it seems absurd to assert this. Unless someone can give us a reason to take the suggestion seriously, I think we can dismiss this response to the Problem of Evil out of hand.

(5.2) is in my view equally hard to deny. Recall that some of the victims of suffering are very small children -- children much too young to have done anything wrong, and hence much too young to have earned any punishment. It is sometimes said that the doctrine of original sin, according to which every human being inherits the moral taint that Adam and Eve incurred by their willful disobedience in Eden, implies that even the smallest children are morally guilty of a serious crime. But I confess that I don't understand how this could be. The suggestion that I might be morally responsible for someone else's transgression simply because he is my father seems to me no more intelligible than the suggestion that I might be morally responsible for the transgressions of someone who happens to look like me or to share my name. If someone were concerned to develop this response without simply appealing to the tradition and authority of the Church, that might be a very interesting project.

(5.3) It is impossible to deny that a great deal of human suffering cannot be traced directly to the voluntary actions of other human beings. It is just barely possible that what we regard as natural evil is really the direct result of free actions of invisible malign spirits or demons. Someone who is willing to believe this can consistently deny the existence of natural evil in our technical sense. Apart from this, I don't see how (5.3) can be rejected.

(5.4) Most responses to the problem evil regard 5.4. as most vulnerable premise. To take this route is to take on the project of showing that each episode of natural evil is strictly necessary for the realization of some very great good -- a good that could not possibly have been realized by any less painful means. This is obviously a very ambitious project: it will not do to show that much or even most of the observed natural evil can be "explained away" in his fashion. The argument only requires a single instance of unnecessary natural evil for its cogency.

Anyone who pursues this route will probably pursue a mixture of strategies. On the one hand, she will try to give detailed accounts of the various goods that come from the most visible and salient natural evils we confront. On the other, she will insist that even we cannot give such an account, this is most naturally explained by our own intellectual limitations. The universe is vast and God's plans are inscrutable. It is not surprising that we cannot easily see that good that comes of the evil we confront in every case.

I will not suggest that this line cannot be made convincing. I will simply point out some pitfalls along the way.

It is sometimes said that the existence of evil is necessary so that we may no the contrast between good and evil. But this is unconvincing for the following reasons:

(a) Even if we it is true that we could not have moral concepts if there were no evil in the world, it does not follow that natural evil is required for this purpose. There is surely enough human evil to provide the incipient moralist with examples of badness. So the argument provides no "justification" for the existence of natural evil.

(b) Perhaps more importantly: It seems wrong to say we could not possibly acquire moral concepts unless there were real instances of evil in the world. It may be that most of us do acquire moral concepts by being presented with instances of good and bad action. But it is surely conceivable that we should have acquired these concepts wholly through encounters with vivid moral fictions -- fairy tells in which the bad guys perform evil acts. Indeed it is conceivable that the concepts of good and evil should have been innate. We do not have to learn how to breathe. Distinguishing between right and wrong might have been similarly instinctive or natural. So there is little to be said for the view that real natural evil is a strictly necessary condition for the acquisition of moral concepts.

It is sometimes said that the reality of natural evil is a necessary condition for the exercise of certain virtues, such as courage, compassion, concern for the well being of others, and so on. A world in which we were permanently protected from harm would be a world in which these good things would have no place. So perhaps the evils we experience are a necessary condition for the realization of these great goods.

But this response, like the previous one, ignores the fact that human evil seems fully sufficient for this purpose. If there were no floods or earthquakes, there might still be war and theft, greed and poverty: and these evils provide ample space for the exercise of the cardinal virtues. So it cannot be said that natural evil is strictly necessary for these great goods.

The point of these examples is to show just how hard it is to establish that natural evil is strictly necessary for some purpose. To show this is to show that some good could not possibly have been achieved by any other less awful means. And that is not easy to do, to say the least.



It remains for us to consider the possibility of rejecting premise 2. Is it possible that a perfectly good God would permit unnecessary natural suffering when he could easily prevent it? It would seem not. After all, if you could easily and at no cost to yourself prevent your neighbor from suffering unnecessarily, then a failure to do so would surely be counted a moral defect in you. Moreover this would be so even if you were under no strict obligation to help your neighbor. It is sometimes said that our strict obligations to act can arise only through voluntary agreements or contracts. On this view, the only way I can come to be under an obligation to perform a certain action is by voluntary placing myself under such an obligation, by making a promise, for example. If this is right, then unless I have made a contract with my neighbor to help him out when he's in trouble, I am entirely within my rights to sit by and watch him suffer. Now let us suppose -- against scriptural authority -- that God has made no promises to us of any sort. It would follow, then, on the view we are presently considering, that God has no obligations to us, and hence that his failure to prevent various natural evils is fully within his rights. With this sort of view in mind, an apologist might try to suggest that when we speak of God's goodness, we mean simply his unwillingness to violate an obligation. Clearly, it is compatible with God's goodness understood in this way that God might permit natural evil in any degree.

This response is formally unobjectionable; but it is very hard to take seriously. If we accept the account of obligation that it involves, then it only goes to show that there is much more to goodness than respecting one's obligations. Even if I have no strict obligation to help my neighbor in the absence of an explicit contract, I would have to be a moral monster to let him suffer when I can easily help him out. A God who was unwilling ever to intervene in cases like this would not be a God worth worshiping, since his "goodness" would be too far removed from the goodness we value in ourselves and our fellows.

I can think of no other way to resist premise 2. Again, it would be very interesting if one of you could do better.