20 Humean Arguments

Another problem arises when we question whether the omni-properties are consistent or coherent with one another. One could claim that any of the traits mentioned above is internally consistent and non-paradoxical, but that the set of traits attributed to God generates contradictions and cannot therefore be possessed by a single entity. Consider the following premise:

Omniscience interferes with free will.

If we take omniscience to include infallible knowledge of every future event, then God knows with absolute certainty that they will do x at a given time t.⁵ If this is true, then it looks as though omniscience interferes with free will. But if omniscience interferes with free will, then it looks as though omniscience also interferes with omnipotence. If God cannot be mistaken about how they will act at t, then God is incapable of doing anything other than x. Thus, we arrive at:

If God lacks free will, then God lacks omnipotence.

And omniscience may also conflict with omnibenevolence. The freedom to do otherwise is often thought of as a precondition for morally good action (I am not performing a praiseworthy action if a mind control device forces me to rescue a drowning child). Yet if God infallibly knows how they will act and thus cannot act otherwise, then one could plausibly argue that there seems to be a similar lack of moral freedom with respect to their actions. So it appears as though omnibenevolence is inconsistent with omniscience, and we can add the following premise to the argument:

3. If God lacks free will, then God lacks omnibenevolence.

If these premises are all true, omniscience interferes with free will, and as a result it interferes with both omnipotence and omnibenevolence. The argument would thus reach the following conclusion:

4. If God is omniscient, God cannot be omnipotent (2) or omnibenevolent (3).

And notice that one could present a different argument that begins with either omnibenevolence or omnipotence, and goes on to claim that either of these properties is inconsistent with the others. Consider:

• 1*. Omnibenevolence seems to interfere with free will
• 2. If God lacks free will, then God lacks omnipotence.

If omnibenevolence amounts to moral perfection, then we can infer that God necessarily does what is morally best in any given scenario. But this is just to say that God cannot do anything that is morally suboptimal. God cannot, therefore, be omnipotent if we take omnipotence to mean an ability to perform morally imperfect actions.

So it appears as though all of the omni-properties can be brought into prima facie conflict (that is, into conflict at first glance) with any of the others. If any of these inconsistencies hold water, then once again, the omniGod cannot exist, because in order to exist, they must possess a set of traits that are logically inconsistent with one another.

Problems of Evil

The omni-properties may be inconsistent not only with each other, but with observable or indispensable facts about the world. In this subsection we shall look at the apparent inconsistency between the omni-properties and the existence of evil. Take the following example:

Suppose in some distant forest lightning strikes a dead tree, resulting in a forest fire. In the fire a fawn is trapped, horribly burned, and lies in terrible agony for several days before death relieves its suffering. (Rowe 1979, 337)

For many philosophers, and many reflective non-philosophers, it is difficult to reconcile the existence of such evils in the world with belief in an omniGod. How could an almighty creator, who brims with loving-kindness, allow any evil to exist in the world, let alone evils of the scale and severity we see in the world today? This apparent tension between the existence of evil and the existence of the omniGod has birthed a number of arguments from evil, designed to show that belief in God is at best unreasonable and at worst outright irrational. Here, we shall focus on moral evils, evils for which some agent is morally responsible or blameworthy. As we shall see at the end of this section, other evils must also be dealt with.

Of those arguments, J. L. Mackie’s argument from evil has been by far the most influential. Mackie argued that belief in the omniGod is irrational because evil could not coexist with a God who possesses two of the omni-properties above. On Mackie’s view, the inconsistency emerges once we begin to flesh out each of omnipotence and omnibenevolence:

1. If God is omnipotent, there are “no limits to what [they] can do” (Mackie 1955, 201).
2. If God is omnibenevolent, they are “opposed to evil, in such a way that [they] always eliminate[ ] evil as far as [they] can” (Mackie 1955, 201).

Together, premises (1) and (2) suggest that if the omniGod existed, evil would not.⁶ The omniGod of Abrahamic theology is perfectly able and entirely willing to eliminate all of the world’s troubles. But it is quite clear, Mackie insists, that evil does exist. The upshot of Mackie’s argument, then, is that if evil exists (and it certainly seems to) then God is either not omnipotent or not perfectly good. In other words, the omniGod does not exist. David Hume articulates this position more forcefully in an oft-quoted passage from his Dialogues Concerning Natural Religion (Hume 1948): “is [God] willing to prevent evil, but not able? Then he is impotent. Is he able, but not willing? Then he is malevolent. Is he both able and willing? Whence then is evil?”⁷

One of the most renowned responses to such problems of evil, defended by philosophers like Plantinga (1974), is known as the free will defence. The free will defence begins with an intuitively plausible premise: free will is very valuable and ought to be preserved. More specifically, the free will defence begins by noting the import of libertarian free will, a capacity to choose your own actions without being caused to act by anything external (e.g. a mind control device or being held at gunpoint). A person exercises libertarian free will whenever their actions are not brought about by outside interference. But this sort of free will therefore requires God’s non-interference. God cannot force us to act in certain ways without thereby sacrificing libertarian free will. So they cannot coerce us into morally upstanding actions without eliminating something of great value. The crux of the free will defence is thus a dilemma. God must choose either to allow us our libertarian free will and in doing so run the risk that we will sometimes act reprehensibly, or to intercede in human life, preventing us from causing evil, but at the cost of our libertarian free will.⁸ Despite possessing the omni-properties, God is faced with forced choices in much the same way we are, and it is better (or more modestly, it could be better for all we know) that God leaves our free will intact.

Many theists find this response satisfying, and it is certainly an elegant solution. But it is a solution which resolves only part of the problem. The free will defence makes sense of evils like murder and theft, which are freely chosen. But some evils seem to have nothing to do with free will at all. More specifically, some philosophers have argued that the free will defence cannot explain natural evils, evils for which no agent is morally responsible or blameworthy—like volcanic eruptions, forest fires, and tsunamis. How, after all, can Rowe’s example above be explained by reference to free will? There is no discernible libertarian free will on which to lay blame there, since such evils are caused by natural processes. So we might think that the free will defence yields only a partial solution to the problem of evil, and that there are other cases of evil which require other solutions.

Chapter Notes

5. Note that this problem does not necessarily threaten classical theists, since on their view God is timeless.

6. Many philosophers go on to add a third premise, taking it to be a hidden or necessary premise in Mackie’s argument:

3. If God is omniscient, he knows about all of the world’s evils and how to eradicate them;

This makes the conclusion a trilemma instead of a dilemma, but the conclusion remains the same – the omniGod still does not exist.

7. Classical theists like Aquinas do acknowledge the challenge evil poses, but the argument plays out rather differently if God is immutable and impassible.

8. The argument thus assumes that God could not have created a world in which people both possess libertarian free will and never bring about evil—a questionable assumption, to be sure, but one we shall not challenge here.