A New Defense of the Problem of Evil

by Hanno

There are two issues in the problem of evil. First, why does evil exist? Second, why does God not do anything about evil? I have no answer to the first, but I can answer the second in a way I am sure has never been used. A solution lies in David Lewis's conception of possible worlds (all of the ersatz versions of Lewis's views will not work, offering perhaps another reason for some to accept Lewis' views.)

Lewis holds that claims like "There are apples," "There are numbers," "There are ways the world might have been," all make existential claims: these things exist. He calls the ways the world might have been "possible worlds" and asserts that they exist exactly like this one. These are not collections of propositions, or ideas in the mind of God, etc., etc.. Each possible world is a universe unto itself, some with people much like you and I, some without. Whenever there is a true sentence like "There might have been no people", it is true because there is a universe (space-time continuum) like this one at which there are no people (it does get more technical, see Lewis Counterfactuals and On the Plurality of Possible Worlds). So, too, for any true claim about what might have been.

Now the idea behind wondering why God does not do anything about evil or suffering is plain enough. If He is all good, he has a moral obligation to end evil and suffering. If he is all powerful, He has the power to end all evil and suffering, and if he is omniscient, he will know how to end all suffering and evil. If he did intervene, he would make this world a better place, reduce suffering and evil.

If Lewis is right, this world is one among an infinite number of worlds. Let us call some evil E, and our world e. The sentence "God could end E" is true at e. That means at some other world, p, God does end E. But here is the deal: for the totality of evil and suffering across possible worlds, there is no change at all. And if he acts here, but might not have, then there is someplace else where he does not act, and hence the evil we avoid here exists on another possible world. Whether God acts or does not act, the total amout of evil and suffering remains the same. Hence, it is not wrong for God to prevent E.

Now if there is no possible world in which E does not exist, then it is impossible for there not to be E. We cannot hold God responsible for not doing the impossible.

Given that He makes a world, if he only makes one, then everything at that possible world is necessary. It is the only possible world. It is then impossible for God to have done otherwise, too. God could not have made another possible world, because the existence of possible worlds is what makes anything possible.

The world exists. It contains evil. Possibilities exist. They can be more or less evil. But it is impossible for the totality of evil to be greater than or less than it is, across possible worlds.

And don't come back with "But that is unbelievable." We are already assuming God's existence. Is that so much easier to believe than Lewis' possible worlds?

Possible Worlds III - Actualism

by Hanno

Lewis held that possible worlds exist exactly like this one. His view entails that there are uncountably many things that exist in "uncountable infinities of donkeys, protons and puddles, of planets very like earth... small wonder if you are reluctant to believe it." Actualist possible worlds tries to use the power of modal logic using actual objects to ground talk of possible worlds. Actualists reject Lewis's view precisely because it is unbelievable.

There are at least three versions of actualist possible worlds semantics. According to Stalnaker, possible worlds are uninstantiated properties. Like the property of being a unicorn, the property exists even if there are no examples of unicorns. In logic-speak, an instance of the property is its instantiation. So uninstantiated properties are properties that nothing has. But for many philosophers, like Plato, the property can exist even if there is no instance.

Alvin Plantinga holds that possible worlds are complete states of affairs. These exist as abstract entities and have properties. The state of affairs "Quine's being a philosopher" has the property of obtaining, while the state of affairs "Quine's being a politician" has the property of not obtaining. Some states of affairs have the property of being possible, and others do not (though Plantinga does not state whether he thinks the imposible states of affairs non-the-less exist). Plantinga has a technical way of defining complete, but basically, for any state of affairs S, a complete state of affairs either includes either S or not S.

According to Robert Adams, possible worlds are not states of affairs, nor abstract objects, but complete, consistent sets of propositions. Propositions are actual intensional abstract entities, and these propositions have the property of being either true or false. A proposition like "Aristotle is tall" contains both the individual Aristotle and the property of being tall. Consistency in complete sets of propositions is inherently modal: It is consistent if it is possible to be true together.

Other philosophers will use a logical notion of consistency, ie, it is consistent iff there is a model which satisfies the set of sentences which mean the propositions. In such a case, anything that is logically consistent is possible, and vise versa. Adams was trying to avoid that conclusion. But the more empiricist philosophers (Hume, Quine, Carnap, early Wittgenstein) all accept that kind of view.

Finally, there are the fictionalists: possible worlds are fictional entities. Just as there are truths about Superman, fiction can ground truth. Just as the fiction of the ideal gas law gives us important truths, so fictional truths can be important. Talk of possibility is grounded on these kinds of important fictions. David Armstrong (not the one at McNeese) holds this kind of view, and cites Wittgenstein as his inspiration.

So possible worlds are: complete consistent states of affairs, complete consistent propositions, complete consistent sets of sentences or made up entities, each version grounding the truth of our modal claims and justifying modal logic.

Possible Worlds II

We were talking about possible worlds being relative to other possible worlds, not relevant, and this is a technical term.

First, for most philosophers, all possible worlds are relative to all possible worlds. This has a consequence that it is governed by a formal logical system called S-5. If not all worlds are possible to all possible worlds, then weaker systems of logic govern our inferences. This is precisely what Kripke showed in his published work in the 1950's, when he was 18(!).

It follows in S-5 that anything which is possibly necessary is actually necessary. this has been used to prove God's existence in a version of the Ontological argument. God, if he exists, has the property of being a necessary being. It is possible that there is a God. Therefore, it is possible that a necessary being exists. By S-5, God is actually necessary, and and since anything which is necessary is true, God exists in this world, too.

Other philosophers deny that all possible worlds are possible relative to all possible worlds. Aristotle might not have existed. So there is a world at which there is no Aristotle. At that world, is it possible that Aristotle's son existed? What does it mean to say that some non-existent thing might have existed? In response to these kinds of questions, they deny the universal connection between possible worlds. Worlds in which Aristotle exists are not possible from worlds in which Aristotle does not exist, though the reverse does not hold. If that is right, the logic of modality is not S-5, but something weaker (S-4, for those who are counting) and it no longer follows that just because something is possible that it is necessarily possible, nor does it follow that something that is possibly necessary is actually necessary.

I am looking at my car. It is possible for it to start. But is it necessarily possible for it to start? On one way of looking at things, no, because it is possible for the engine block to be totally ruined. Spelling that out in possible worlds means some possible worlds are not possible from all possible worlds. It is possible that Aristotle exists. But is it necessarily possible? What if human beings never develop? What if the world blew up before humans ever appear on the world stage? Then there would still be a possible world in which Aristotle exists ("Aristotle might have existed" is true), but that world would not be relatively possible from worlds where the world blows up before humans arrive on the scene. Hence we can say Aristotle could not exist if the world blew up before humans arrive on the scene, even though he might exist in other circumstances.

Hope that helps.

I was going to post more on the metaphysics of modality, but ce side tracked me. Blame him. Will try to do that Monday.