Alvin Plantinga's Free Will Defense - Plantinga's Argument

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".