Friday, May 28, 2010

Yet another ontological argument

I've never heard the following version of the ontological argument put quite in this way, though there may be things in Anselm and Descartes that suggest it:

  1. (Premise) An impossible being is imperfect.
  2. A perfect being is possible. (By (1))
  3. (Premise) Necessarily, a contingently existing being is imperfect.
  4. A perfect being exists necessarily. (By 2 and 3)
  5. (Premise) What exists necessarily also actually exists.
  6. A perfect being actually exists. (By 4 and 5)
I don't know if (2) validly follows from (1). Or maybe there is a problem with (1), in that we simply cannot attribute about impossibilia?

Why believe (1)? Well, one line of thought is that impossibility is an impotence. Another is that an impossible property entails all properties, and in particular such properties as being imperfect, and no imperfect being is perfect.

6 comments:

Douglas said...

Neat argument.

1 might be ambiguous with respect to negation. 1 might mean the same thing as "It is not the case that: an impossible being is perfect" which appears true because there are no impossible beings. That truth does not entail 2. Or 1 might mean that an impossible being has the property of imperfection, which seems false. There are no impossible beings, so perhaps there are none with properties.

Third, 1 might mean that everything is either possible or imperfect, in which case 1 is true. But then the argument is valid only if 2,3, 4, 5, and 6 mean such things as: everything is imperfect or possible, etc. The conclusion such premises appear to yield (that everything is imperfect or actually exists) is not the conclusion sought.

Perhaps the best way to read "An impossible being" in 1 is as introducing a restricted quantification over impossible beings (so 1 is not a universally quantified conditional or disjunction). I don't like that one bit, and it still yields a conclusion that's perhaps too weak when the other premises are read similarly.

Alexander R Pruss said...

I think the argument needs quantification over thinkables, or something like that. Then, (1) says that none of the impossible thinkables is perfect.

Douglas said...

That's a nice way to read 1. I wonder how one gets back to quantification over objects straight at (6), or whether one needs to.

Alexander R Pruss said...

I think premise 5 makes that move work. Or so this argument says.

larryniven said...

"Third, 1 might mean that everything is either possible or imperfect, in which case 1 is true."

Careful: you and I are imperfect and possible. I assume you didn't mean to say "either," but...

Anyway, Alex, 1 and 2 use "is possible" differently. More on this over on my blog I think tomorrow.

Alexander R Pruss said...

An impossible being is a being that exists at no world, and a possible being is a being that exists at some world. That's what I mean in 1 and 2.