Dr. Retard

Hold on, if that's true, then all non-self-contradictory things are logically possible. In which case, we can get out all the familiar parodies. The "necessary big pile of feces" is then logically possible, and so necessary, and so actual.

Thomas Metcalf

Originally posted by mattbballman :

Please point me to where you have demonstrated that conclusion. I've provided a very clear counterexample: consider the non-contingent being that fails to exist in one possible world. This being is impossible, but it is not self-contradictory. So not only will you have to support your above claim, but you'll also have to find a reason to reject my counterexample.

Further, as Dr. Retard has pointed out, your statement entails that all non-self-contradictory things are not logically impossible. So the door's open for a host of parodies. The non-contingent machine that turns the sky green for one daylight hour every day is not self-contradictory and not contingent, so it must be necessary. I must not have been watching while the sky turned green yesterday.

mattbballman

tom,

(i) Your thesis is not convincing in light of those so-called examples you gave about a logically impossible item (a green sky) which turn out to be factually impossible things instead. You haven't commented on these further but have imagined them away. The only tactic you can take here, other than finding just such a counterexample, is to define "logically impossible" as something other than the traditional view.

(ii) If a necessarily existing machine that turns the sky green for one hour each day exists then it necessarily turns the sky green one hour each day. The sky does not turn green one hour each day. Therefore, a necessarily existing machine does not exist. This is not a conceptual problem (like a logically impossible entity) but a factual one since the sky in fact does not turn green one hour each day. However, stripped of references to the actual world (a broadly logically possible world), such a machine is conceivable. But the facts of the actual world insure that the machine is non-existent (and, thus, not non-contingent).

matt

Thomas Metcalf

mattbballman ,

Consider the following thesis, which you seem to be propounding:

(CCT) Complete Coincidence Thesis: All logically impossible things are self-contradictory and all self-contradictory things are logically impossible.

And let M be the necessarily existing machine that turns the sky green for one hour every day. I don't think CCT is supportable, but moreover, I think it is obviously false. Consider the following argument:

1. If (CCT) is true, then if M is logically impossible, then M is self-contradictory. (Analytic truth.)
2. M is not self-contradictory.
3. M is logically impossible.
4. Therefore, it is not the case that if M is logically impossible, then M is self-contradictory. (Theorem of logic.)
5. Therefore, (CCT) is false. (Modus tollens.)

Do you deny 2, or do you deny 3, or do you deny both 2 and 3? If you deny 2, you must show that something within the definition of M contradicts something else within the definition of M. I don't think you can do that. So you'd have to deny 3, but the denial of 3 entails that the sky turns green for one hour every day. So I don't think you can deny 3 either.

K

mattbballman:

You have just demonstrated that mere logical non-contradiction is insufficient to to meet the "possible" requirment of the ontological argument. You have agreed that there exists a description of a logically non-contradicting entity that is still impossible in the real world.

mattbballman

metcaf,

Actually, this first premise should read If (CCT) is true, then M is logically impossible iff M is self-contradictory. Otherwise one could simply deny statement 3 and the falsity of CCT (statement 5) would not follow. A biconditional secures the dilemma of 2 and 3.]

The problem remains to be an equivocation with "logical impossibility." In the first premise one means by logical impossibility that which is epistemically/conceptually/broadly impossible. In the third premise one means by logical impossibility that which is metaphysically/factually/narrowly impossible. So I have recommended that you specify "logical impossibility" apart from "factual impossibility" so as to avoid such equivocation. But in so doing, one must abandon your specific objection to McHugh. Believe me, it is more healthy to concentrate on this issue of reification which is the typical response to the ontological argument. If you continue to take the 5-step assumption above, your criticism will be dead on arrival everytime!

matt

Thomas Metcalf

Originally posted by mattbballman :

2 and 3 by a theorem of logic entail the denial of the consequent of the broadest conditional in 1. And the denial of that consequent entails the denial of its antecedent. So I don't see what the problem is. To deny 3 does indeed fail to deliver the denial of 5, but that doesn't matter for the argument. There's nothing wrong with the form of the argument.

Here's a schematized version:

1. P --> (R --> S)
2. -S
3. R
4. -(R --> S)
5. -P

It's obviously valid if I phrase it that way. You're asking for:
1''. P --> (R <--> S)

The argument works that way too, but 1'' is unnecessary when 1 will do, especially because 1 follows from 1''.

Huh? I've only meant alethic logical possibility whenever I've said "logically possible." And I've only meant the possible-worlds analysis. To prove it, I'll replace all logical possibility talk with possible-worlds talk and the argument will remain sound:

(CCT') Modified Complete Coincidence Thesis: All things that exist in no possible worlds are self-contradictory and all self-contradictory things exist in no possible worlds.

1'. If (CCT') is true, then if M exists in no possible worlds, then M is self-contradictory. (Analytic truth.)
2. M is not self-contradictory.
3'. M exists in no possible worlds.
4'. Therefore, it is not the case that if M exists in no possible worlds, then M is self-contradictory. (Theorem of logic.)
5'. Therefore, (CCT') is false. (Modus tollens.)

Now tell me whether you deny 2 or 3'.

mattbballman

tom,

My point is that you don't understand possible worlds semantics. When one speaks of logical possibility, she could mean one of the two ways I noted. Possible worlds semantics can typically be referred as actualizability which is not clearly defined unfortunately. For example,

(i) The Prime Minister is a prime number

is not broadly logically impossible, but neither is it true in any possible world. Instead, it is metaphysically/narrowly logically impossible. What you have to do is specify one and when you do, then your goal is defeated because your argument depends on linking these two versions of logical impossibility. The fact is, per this analogy, statement 1' above is wrong. But if you say that "If (CCT) is true, then if M is broadly logically impossible, then M is self-contradictory" then this will make the argument now invalid because a new term is introduced that the other premises do not handle. In short, you are trying to pull the wool over the eyes of your opponents. And here's an example of how you're doing it:

A. Joe is someone who quit smoking.
B. Nobody likes a quitter.
C. Therefore, nobody likes Joe.

The only way this argument will be successful, as unsavory as the conclusion might be, depends on a univocal meaning for "quit." One can insist that there is a univocal meaning for "quit" but the premises betray that notion. Similarly, your reconstruction that uses "possible worlds" is no more univocal. Is it actualizability, broad logical possibility, or narrow logical possibility?


matt

Thomas Metcalf

mattbballman :

I still don't think you're getting anywhere, even if we further specify what we're talking about.

(CCT-N): Iff something is narrowly logically impossible, then it is self-contradictory.

1. If (CCT-N) is true, then if M is narrowly logically impossible, then M is self-contradictory.
2. M is not self-contradictory.
3. M is narrowly logically impossible.

... and so on. Something can be narrowly logically impossible and not be self-contradictory. That's the way it works with God. He's not self-contradictory, but he still doesn't exist in any possible world, because he doesn't exist in every possible world.

McHugh cannot rule out narrow logical impossibility, even if he can rule out broad logical impossibility. And he must rule out narrow logical impossibility, as I see it, to conclude that God exists in the actual world.

Golgo_13

How many times do I have to reiterate that supernatural deities cannot be argued into existence.