The latest (July 2011) Faith and Philosophy contains an excellent article by Jeff Speaks on some difficulties related to establishing the consistency of certain claims (he uses as examples the existence of human freedom and the existence of evil) with the existence of an Anselmian God. The basic idea is this: since an Anselmian God is, by definition, a necessary being, establishing the possibility of an Anselmian God is tantamount to establishing the necessary, and therefore actual, existence of an Anselmian God. But these compatibility arguments typically, in one way or another, assume the possibility, and so the actuality, of an Anselmian God. If we were allowed to assume this premise, our task would be extremely easy! We could argue as follows:
In his paper, Speaks argues that Warfield's argument for the compatibility of necessary omniscience with human freedom and Plantinga's free will defense are both a lot like this. That is, they both assume that, possibly, an Anselmian God exists. But if that assumption is admissible, then we could just use this simpler argument. But obviously we can't use this simpler argument, so the premise must be inadmissible. (This isn't exactly the way Speaks puts his points together; it's my interpretation of what his arguments actually show.)
Speaks states the "principal conclusion" of his paper as follows:
any argument for the compatibility of two propositions must also be an argument for the possibility of each of those propositions. Hence it is impossible to argue for the compatibility of two propositions, one of which is necessary if possible, without arguing for the truth of that proposition. (p. 291)
In this post, I'm going to push back. Specifically, I believe that the standard (Lewis-Stalnaker) semantics for subjunctive conditionals is flawed in its treatment of impossible antecedents, and that once we recognize this flaw for what it is, we can save these compatibility arguments (though, for reasons which will emerge, it might be better to call the modified arguments 'might' arguments, or some such). I should note that my suggestion is in some ways similar to a suggestion Speaks makes at the end of his paper, namely, that if we had a notion of some sort of asymmetric 'dependence' relation which could obtain between necessary truths, we might show that God's existence and human freedom are, in this sense, independent. But my solution will require only subjunctive conditionals, and not these additional dependence relations.
I'm going to use Plantinga's Free Will Defense as my example since it's more familiar to me, and probably to most readers, than Warfield's argument. I'll use the following symbols:
|□→||The 'would' subjunctive, as in 'If I were to flip this coin, it would land either heads or tails.'|
|◊→||The 'might' subjunctive, as in 'If I were to flip this coin, it might land heads.'|
|G||The proposition that necessarily, an omnipotent, omniscient, and morally perfect being exists.|
|E||The proposition that evil exists|
|TWD||The proposition that every creaturely essence suffers trans-world depravity (if you don't know what that means, you should read Plantinga's The Nature of Necessity, but I think you'll be able to understand most of what I say without it).|
Now, we can think of the argument from evil as going like this:
(FWD) G ◊→ E
Now, slightly modifying Plantinga, we can run the argument as follows
This implication of the standard semantics is, I submit, incorrect. I think the following conditional is true:
If some humans were able to draw round squares, I might be able to draw round squares.
If mereological universalism were true, then my body might be part of an object which also had an alien space ship as a part.
(cross-posted at The Prosblogion)Posted by Kenny at November 19, 2011 12:51 PM
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