Tuesday, September 8, 2009

The ontological argument and the semantic paradoxes

I've been feeling that there is some kind of an analogy between Anselm's version of the Ontological Argument (OA) and semantic paradoxes like the Liar or Curry's. Here is one analogy. I've argued in an earlier post that when the consequent in material-conditional Curry sentences is true, the Curry sentence is true, and when the consequent is false, the Curry sentence is nonsense. (The Curry sentence with consequent p is: "If this sentence is true, then p." There is a cool argument from the meaningfulness of the sentence to p.) If this is right, then we have a valid way of arguing from meaning to truth: We have sentences that are true if and only if they are meaningful (for when the consequent is true, the whole sentence is true). Now, I've always thought that Anselm's argument went through as soon as it were granted that one had a concept of that than which nothing greater can be conceived. However, as St. Anselm himself notes but does not make enough of, to have a concept is more than just have a sequence of words in one's head. Thus, it may well be that we have the sequence of words without them expressing a concept.

Just as the Curry sentence is true iff it expresses a proposition, so too the Anselmian predicate has a satisfier (i.e., God) iff it expresses a property. At the same time, this suggests a caution. It would be mistaken to try to figure out by introspection whether a Curry sentence with empirical consequent expresses a proposition, and likewise it may not be appropriate to figure out by introspection whether the Anselmian predicate expresses a property.

3 comments:

Mike Almeida said...

. . .and likewise it may not be appropriate to figure out by introspection whether the Anselmian predicate expresses a property

Not sure what you mean by 'figure by introspection', but traditional Anselmianism holds that, for all essential properties P of God, it is apriori true that God has P (perhaps with some uninteresting exceptions). If for all God properties P, it is apriori God has P, then certainly (no question about it) the conceivability of God entails the possibility (and actuality) of God. The only remaining question concerns whether God is conceivable. And that does seem to involve introspection of some sort.

Alexander R Pruss said...

By "the Anselmian predicate" I meant the predicate "is such that nothing greater than it can be conceived." If this predicate denotes a property, then we can conceive of something that has that property, simply by thinking about that which "is such that nothing greater than it can be conceived."

Mike Almeida said...

If this predicate denotes a property, then we can conceive of something that has that property, simply by thinking about that which "is such that nothing greater than it can be conceived.

No, definitely this is true. The knee-jerk reply that conceivability does not entail possibility is just mistaken in this context. Conceivability does entail possibility for the traditional Anselmian position. And that is more or less what you're saying, I think.
But this cuts the other way, too, and in very interesting ways. All you need is, say, the conceivability of something suffering gratuitously to refute Anselmianism of this sort. It need not be so much as possible, so long as it is conceivable! All you need is conceivability since Anselmianism of this sort rules out such cases apriori. I don't think many Anselmians notice this serious vulnerability in their position.