Friday, October 15, 2010

Towards a necessary being

Start with these premises:

  1. It is a contingent fact that there are contingent beings.
  2. No one can believe that there is nothing.
  3. Necessarily, if p, then it is possible that someone believes that p.
It follows from (2) and (3) that:
  1. It is not possible that there is nothing.
For if it were possible that there is nothing, then at some world there would be nothing, and it would follow by (3) and S4 that it is possible that someone believes that there is nothing, contrary to (2). But (4) is equivalent to:
  1. Necessarily, there is something.
But by (1), there is a possible world with no contingent beings. Since (5) assures us that there is something at that world, it must be something necessary. Hence:
  1. Possibly, there is a necessary being.
And by S5:
  1. There is a necessary being.

We can do one better. Replace (2) with:

  1. No one can believe there are no thinkers.
It follows from (3) and (8) that:
  1. It is not possible that there are no thinkers.
By (1) it is possible that there are no contingent beings. Therefore:
  1. Possibly, there is a necessary being who is a thinker.
And by S5:
  1. There is a necessary being who in at least some worlds is a thinker.

That said, I don't know if (2) and (8) are true.

13 comments:

Derrick said...

I think that most who want to deny that there is a necessary being would attack (1). Why shouldn't we think that it's a necessary de dicto that something exists while there's nothing that necessarily exists?

Alexander R Pruss said...

The view that there necessarily is something contingent has the following consequence: necessarily, if there were no non-unicorns, there would be a unicorn. If one is attracted to recombination as a guide to possibility, this is implausible.

Mike A Robinson said...

Leibnez asserted: “Therefore, God alone (or the Necessary Being) has this prerogative that if he be possible he must necessarily exist, and as nothing is able to prevent the possibility of that which involves no bounds, no negation, and consequently no contradiction, this alone is sufficient to establish a priori his existence.”
How does his a priori assertion relate to the a posteriori portion of your argument?

And does the assertion of “no one” (a universal claim) made by you in premise 2 confute your argument since you lack universal knowledge?

awatkins69 said...

I think this argument is sound. What do you think about the gap problem here?

Steve Finnell said...

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Doug Benscoter said...

I'm curious about a similar argument which, albeit does not establish the existence of a logically necessary being, argues at the very least that a temporally necessary being exists. I add asterisks to each premise in order to distinguish the argument from Dr. Pruss':

1*. Every existing being is either temporally contingent or temporally necessary. (Definition)

2*. Necessarily, something has always existed. (Premise)

3*. Possibly, there was a past time in which nothing temporally contingent existed. (Premise)

4*. Therefore, a temporally necessary being exists. (Conclusion)

Validity:

Assume (5*): a temporally necessary being does not exist. (5*) and (2*) imply (6*): necessarily, something temporally contingent has always existed. (6*) contradicts (3*). Therefore, (5*) is false.

The argument just seems too easy, but maybe I shouldn't think of ease of argument as a problem. Am I making a mistake somewhere?

Alexander R Pruss said...

Doug:

This is kind of like the third way.

For the argument to work, the "Possibly" in premise 3 has to be a temporal possibly, which I assume means: "At some time or other". But why think that at some time or other nothing existed? Maybe time itself had a beginning, and with its beginning there was the beginning of all beings in time.

Doug Benscoter said...

I think that's true. I suppose one could think of the temporally necessary being existing in a kind of undifferentiated time "before" anything temporally contingent was brought about. I'm not sure if that answers your question, though.

Kief said...

What justification do we have for premise 3?

awatkins69 said...

Also, as you said, 2 seems questionable. Null-world, yes?

Alexander R Pruss said...

Kief:

Maybe some idea that propositions are believables?

My own reason for believing 2 depends on the conclusion of the argument. :-)

awatkins69:

It would be kind of weird to believe that nothing exists--not even oneself.

David said...

Suppose that p is "It's not possible that anyone has a belief." Then if p, it's not possible that anyone believes p. This appears to be a counter instance to premise (3).

Alexander R Pruss said...

The antecedent is false, so the conditional is true. :-)