Wednesday, May 29, 2013

A deontic-ontological argument

  1. There ought to be a perfect being.
  2. What ought to be is possible. (Ought implies can.)
  3. If a perfect being is possible, there is a perfect being. (By S5 and as a perfect being is necessarily existent and essentially perfect.)
  4. So, there is a perfect being.

10 comments:

Kenny said...

Does the impersonal ought really imply can? The principle 'if S ought to A, then S can A' is very different from the principle, 'if it ought to be the case that p, then it can be the case that p.'

By the way, you may have seen that Klaas Kraay recently got a Templeton grant to figure out whether there really ought to be a perfect being! http://www.ryerson.ca/~kraay/theism.html

Heath White said...

What Kenny said.

Alexander R Pruss said...

My own worry is about whether there is any non-agential ought.

Brian Cutter said...

A similar argument, which avoids worries about whether there is a non-agential "ought" (and maybe sort-of avoids worries about whether the non-agential "ought," if such there be, implies "can"):

1. It would be better if there were a perfect being than if there weren't a perfect being.
2. For any p, if (it would be better if p than it would be if not-p), then Possibly(p).
3. Therefore, there is a perfect being (again, given S5 and the assumption that a perfect being would exist necessarily and be essentially perfect).

(1) looks very plausible, so I think the key premise is (2). I can't think of any obvious counterexamples to it at the moment, but I wouldn't be surprised if there are some.

David Balcarras said...

This is essentially Carl Kordig's argument from his "A Deontic Argument for God's Existence".

Here's a problem, for both the original argument and Cutter's:

(P1) It would be worse if there were not a perfect being than if there weren't a perfect being.
(P2) For any P, if (it would be worse if P than it would be if not-P), then possibly P.
(P3) Thus, there is no perfect being. (S5, necessary existence of perfect being)

If the world would be worse off without God, then, if ought (ought not) implies can (can not), God doesn't exist.

Crude said...

I have a question of my own about this.

Let's say the B-theory of time is true. (I'm on shaky ground here, but I think I understand the fundamentals.) Is it possible that this argument can success, but for the perfect being to only exist in some place that isn't the present?

Alexander R Pruss said...

A perfect being is not limited in its existence. In particular, it is not temporally limited.

Alexander R Pruss said...

David:

I don't see much reason to accept the principle that if p makes things worse, then p is possible. Contradictions being true makes things worse, arguably, but it's not possible.

Ex Nihilo said...
This comment has been removed by the author.
analyticphilosopher said...

The second premise of Brian's argument is

2. For any p, if(it would be better if p than it would be if ~p) then possibly p.

What about this apparent counterexample:

It would be better if it is true that I never sin in the actual world than it would be if it is false that I never sin in the actual world.

But if (2) is true then it is possible that it is true that I never sin in the actual world. Given that I do sin in the actual world, it is clearly impossible that it be true that I never sin in the actual world. So (2) must be false.