Alvin Plantinga's free will defense

Alvin Plantinga in 2004

Alvin Plantinga's version of the free will defense is an attempt to refute the logical problem of evil: the argument that the existence of an omnipotent, omniscient, omnibenevolent God in an evil world is a logical contradiction.

The core of the argument is the definition of "omnipotence". Plantinga argues that God, in spite of being omnipotent, has some limitations on his power.

Plantinga's argument is that "It is possible that God, even being omnipotent, could not create a world with free creatures who never choose evil. Furthermore, it is possible that God, even being omnibenevolent, would desire to create a world, which contains evil if moral goodness requires free moral creatures." While Plantinga's free will defense has received fairly widespread acceptance among theologians, many still contend that it fails to adequately resolve the problem of evil, or that it only addresses moral evil, not natural evil, or that it requires an incompatibilist libertarian view of free will in order to be effective.

Logical problem of evil

Main article: Problem of evil

The logical problem of evil emerges from four core propositions:

1. An all-powerful (omnipotent) God could prevent evil from existing in the world.
2. An all-knowing (omniscient) God would know that there was evil in the world.
3. An all-good (omnibenevolent) God would wish to prevent evil from existing in the world.
4. There is evil in the world.

As J. L. Mackie has highlighted, there would appear to be a contradiction between these propositions such that they cannot all be true. Given that the fourth proposition would appear to be undeniable, it can be inferred from the above that one of the other three must be false, and thus there cannot be an all-good, all-knowing and all-powerful God. To put it another way, if God does exist, He must be either "impotent, ignorant or wicked".

The problem, and various solutions to it, have been debated by philosophers since at least the time of Epicurus in the fourth century BC. One of the most historically significant replies to the problem is the free will theodicy of Augustine of Hippo, which has been extensively criticized.

Plantinga's argument

As opposed to a theodicy (a justification for God's actions), Plantinga puts forth a defense, offering a new proposition that is intended to demonstrate that it is logically possible for an omnibenevolent, omnipotent and omniscient God to create a world that contains moral evil. Significantly, Plantinga does not need to assert that his new proposition is true, merely that it is logically valid. In this way Plantinga's approach differs from that of a traditional theodicy, which would strive to show not just that the new propositions are sound, but that they are also either true, prima facie plausible, or that there are good grounds for making them. Thus the burden of proof on Plantinga is lessened, and yet his approach may still serve as a defense against the claim by Mackie that the simultaneous existence of evil and an omnipotent and omnibenevolent God is "positively irrational".

As Plantinga summarised his defense:

A world containing creatures who are significantly free (and freely perform more good than evil actions) is more valuable, all else being equal, than a world containing no free creatures at all. Now God can create free creatures, but He can't cause or determine them to do only what is right. For if He does so, then they aren't significantly free after all; they do not do what is right freely. To create creatures capable of moral good, therefore, He must create creatures capable of moral evil; and He can't give these creatures the freedom to perform evil and at the same time prevent them from doing so. As it turned out, sadly enough, some of the free creatures God created went wrong in the exercise of their freedom; this is the source of moral evil. The fact that free creatures sometimes go wrong, however, counts neither against God's omnipotence nor against His goodness; for He could have forestalled the occurrence of moral evil only by removing the possibility of moral good.

Plantinga's argument is that even though God is omnipotent, it is possible that it was not in his power to create a world containing moral good but no moral evil; therefore, there is no logical inconsistency involved when God, although wholly good, creates a world of free creatures who chose to do evil. The argument relies on the following propositions:

1. There are possible worlds that even an omnipotent being can not actualize.
2. A world with morally free creatures producing only moral good is such a world.

Plantinga refers to the first statement as "Leibniz's lapse" as the opposite was assumed by Leibniz. The second proposition is more contentious. Plantinga rejects the compatibilist notion of freedom whereby God could directly cause agents to only do good without sacrificing their freedom. Although it would contradict a creature's freedom if God were to cause, or in Plantinga's terms strongly actualize, a world where creatures only do good, an omniscient God would still know the circumstances under which creatures would go wrong. Thus, God could avoid creating such circumstances, thereby weakly actualizing a world with only moral good. Plantinga's crucial argument is that this possibility may not be available to God because all possible morally free creatures suffer from "transworld depravity".

Transworld depravity

Plantinga's idea of weakly actualizing a world can be viewed as having God actualizing a subset of the world, letting the free choices of creatures complete the world. Therefore, it is certainly possible that a person completes the world by only making morally good choices; that is, there exist possible worlds where a person freely chooses to do no moral evil. However, it may be the case that for each such world, there is some morally significant choice that this person would do differently if these circumstances were to occur in the actual world. In other words, each such possible world contains a world segment, meaning everything about that world up to the point where the person must make that critical choice, such that if that segment was part of the actual world, the person would instead go wrong in completing that world. Formally, transworld depravity is defined as follows:

A person P suffers from transworld depravity if and only if the following holds: for every world W such that P is significantly free in W and P does only what is right in W, there is an action A and a maximal world segment S´ such that

1. S´ includes A 's being morally significant for P
2. S´ includes P 's being free with respect to A
3. S´ is included in W and includes neither P 's performing A nor P 's refraining from performing A
4. If S´ were actual, P would go wrong with respect to A.

Less formally: Consider all possible (not actual) worlds in which you always choose the right. In all those, there will be a subpart of the world that says you were free to choose a certain right or wrong action, but does not say whether you chose it. If that subpart were actual (in the real world), then you'd chose the wrong.

Plantinga says that "What is important about the idea of transworld depravity is that if a person suffers from it, then it wasn't within God's power to actualize any world in which that person is significantly free but does no wrong—that is, a world in which he produces moral good but no moral evil" and that it is logically possible that every person suffers from transworld depravity.

Reception

According to Chad Meister, professor of philosophy at Bethel College, most philosophers accept Plantinga's free will defense and thus see the logical problem of evil as having been sufficiently rebutted. Robert Adams says that "it is fair to say that Plantinga has solved this problem. That is, he has argued convincingly for the consistency of God and evil." William Alston has said that "Plantinga [...] has established the possibility that God could not actualize a world containing free creatures that always do the right thing." William L. Rowe has written "granted incompatibilism, there is a fairly compelling argument for the view that the existence of evil is logically consistent with the existence of the theistic God", referring to Plantinga's argument.

In Arguing about Gods, Graham Oppy offers a dissent, acknowledging that "[m]any philosophers seem to suppose that [Plantinga's free will defense] utterly demolishes the kinds of 'logical' arguments from evil developed by Mackie" but continuing "I am not sure this is a correct assessment of the current state of play". Concurring with Oppy, A.M. Weisberger writes “contrary to popular theistic opinion, the logical form of the argument is still alive and beating.” Among contemporary philosophers, most discussion on the problem of evil presently revolves around the evidential problem of evil, namely that the existence of God is unlikely, rather than illogical.

Criticisms

Derk Pereboom while acknowledging that "many of those involved in this debate agree that Plantinga has provided a successful response to the abstract logical problem of evil", delineates a number objections, including the following:

• Michael Tooley insists that the more pressing problem is the logical compatibility of the existence of God with the actual evils in the world, a problem referred to as "the logical problem of horrendous evil" by Marilyn McCord Adams.
• David Lewis argues that even if each person would go wrong for some world segments, it would be possible for God to cause the person to do the right thing in just these cases, preserving selectively some significant moral freedom.

Incompatibilist view of free will

A simplified taxonomy of the main positions on the nature of free will.

Critics of Plantinga's argument, such as philosophers J. L. Mackie and Antony Flew, have responded that it presupposes a libertarian, incompatibilist view of free will (free will and determinism are metaphysically incompatible), while their view is a compatibilist view of free will (free will and determinism, whether physical or divine, are metaphysically compatible). The view of compatibilists such as Mackie and Flew is that God could have created a world containing moral good but no moral evil. In such a world people could have chosen to only perform good deeds, even though all their choices were predestined. Plantinga dismisses compatibilism, according to which a person is free if, and only if she could have done otherwise if she wanted to do otherwise by saying that it is "altogether paradoxical". He thinks that "this objection... seems utterly implausible. One might as well claim that being in jail doesn't really limit one's freedom on the grounds that if one were not in jail, he'd be free to come and go as he pleased". Regarding Flew's criticism Plantinga concludes that "his objection is in an important sense merely verbal and thus altogether fails to damage the free will defense."

The problem of natural evil

Another issue with Plantinga's defense is that it does not address the problem of natural evil, since natural evil is not brought about by the free choices of creatures. Plantinga's reply is a suggestion that it is at least logically possible that perhaps free, nonhuman persons are responsible for natural evils (e.g. rebellious spirits or fallen angels). This suggestion assigns the responsibility for natural evils to other moral actors.

"Omnipotent God" of Alvin Plantinga has limited power

A recent objection to the defense is due to Geirsson and Losonsky, who question the interpretation of the fourth assertion in the definition of transworld depravity ("If S´ were actual, P would go wrong with respect to A"). This is a contingent fact: it is true in the actual world, but false in the world W. So one may ask if this contingent fact was up to God or not. If it was caused to be true by God, one may wonder why God actualized a world in which this person is transworld depraved when God could have actualized a world where this person, at least with respect to this action, would not suffer from such conditional depravity. If on the other hand, the fact is not up to God, we must accept that an omnipotent God has no power over contingent facts about the world; after all, there do exist possible worlds where the conditional statement in question is not true. Geirsson and Losonsky note that Mackie's reasons for rejecting Plantinga's defense were quite similar:

But how could there be logically contingent states of affairs, prior to the creation and existence of any created beings with free will, which an omnipotent God would have to accept and put up with? This suggestion is simply incoherent.

Despite these objections, many philosophers consider Plantinga's defense, with its implicit libertarianism, to be a strong reply to the logical problem of evil. However, other philosophers argue that Plantinga's defense is unsuccessful.

External links

• Raymond D. Bradley. The Free Will Defense Refuted and God's Existence Disproved, 2007
• Justin Ykema. A critique of the free will defense, 2013