Thursday, November 16, 2017

Truth-value open theism

Consider the view that there are truth values about future contingents, but (as Swinburne and van Inwagen think) God doesn’t know future contingents. Call this “truth-value open theism”.

  1. Necessarily, a perfectly rational being believes anything there is overwhelming evidence for.

  2. Given truth-value open theism, God has overwhelming but non-necessitating evidence for some future contingent proposition p.

  3. If God has overwhelming but non-necessitating evidence for some contingent proposition p, there is a possible world where God has overwhelming evidence for p and p is false.

  4. So, if truth-value open theism is true, either (a) there is a possible world where God fails to believe something he has overwhelming evidence for or (b) there is a possible world where God believes something false. (2-3)

  5. So, if truth-value open theism is true, either (a) there is a possible world where God fails to be perfectly rational or (b) there is a possible world where God believes something false. (1,4)

  6. It is an imperfection to possibly fail to be perfectly rational.

  7. It is an imperfection to possibly believe something false.

  8. So, if truth-value open theism is true, God has an imperfection. (6-7)

And God has no imperfections.

To argue for (2), just let p be the proposition that somebody will freely do something wrong over the next month. There is incredibly strong inductive evidence for (2).

12 comments:

Walter Van den Acker said...

I guess the open theist would argue that, since it is impossible to know every future contingency, not knowing some future contingency is not an imperfection, in the same way not being able to create a square circle is not an imperfection.

Also, I don't think it is true that necessarily, a perfectly rational being believes anything there is overwhelming evidence for. If there is a possible world in which there is overwhelming evidence for p, yet p is false, then a prefectly rational being knows that there is such a possible world, hence, a perfectly rational being believes there is overwhelming evidence for p, but cannot conclude from this that p is true. All a perfectly rational being can conclude is that p is very likely true but has a small, but non-zero probability of being false.

Jensen Carlyle said...

Couldn't the argument, at least suitable modified, go through without (1). Instead one only need to say that "A perfectly rational being could believe anything there is overwhelming evidence for." Because, doesn't this still show that in some possible world God believes something that is false?

Now, why is it a defect in perfect rationality (and hence not actually perfect rationality) to have a false, but eminently justified belief? Do you think that you and I can hold justified beliefs which turn out to be false without slighting our rationality? Why couldn't God?

But maybe our beliefs are justified relative to only some facts, X, Y and Z but not others which we are not aware of, 1, 2 3 - but God knows all of these. And this turns out to be important. Or maybe I'm using rationality in an equivocal sense from you. I'm not even certain what I mean, something like: 'Ability to reason from known facts to reasonable conclusions' and maybe this equivocation is important to my not understanding this point.

It seems to me that you mean "non-necessitating" evidence as that evidence that doesn't necessitate the proposition in question be true. But if so why does such evidence necessitate that any perfectly rational being with access to it believe the proposition in question?

Alexander R Pruss said...
This comment has been removed by the author.
Alexander R Pruss said...

I don't think you can make the weaker version go through without further changes, because it could be that the perfect being believes the thing in a world where it is in fact true.

I agree that false belief doesn't slight our rationality. But it is still an imperfection, just like having limited power is an imperfection but not an imperfection contrary to rationality.

Walter Van den Acker said...

False belief may be an imperfection, hence believing that p is true while P is false is an imperfection.
But I dont think an open theist will agree that God can have false beliefs. I am not an opne theist, but I think open theists will probably say that God neither believes p is true nor that p is false. Rather God believes that there is a non-zero probability that p is true and there is also a non-zero probability that p is false.

Having limited power is an imperfection but not being able to do something that is logically impossible does not qualify as limited power.

Jensen Carlyle said...

I suppose this not yet formulated altered argument could show that God isn't necessarily perfect, which seems less than ideal for a theist to maintain. Or, Walter or Alex, do you think that there is a reason why God, given his perfect rationality, couldn't hold that for which there isn't certain evidence for? That seems to be what you're hypothetical open theist says, Walter. However, if it's justified to be held, isn't this sufficient for one to hold that belief. It seems to be in our case, so why not to the open theist God?

And yes, I see your point that an imperfection in the form of a false belief needn't slight one's rationality.

Well, now to pick all the pictures with cars or street signs.

Walter Van den Acker said...


Jensen
The reason why god, given His perfect rationality, couldn't hold that for which there isn't certain evidence for is that holding a belief that something is true while it might be false is not rational.

Jensen Carlyle said...

But aren't we still rational to accept that for which their is compelling, if not certain, evidence for something? Is our doing so a defect of our rationality?

I suppose it could be that it isn't for us, but for God it is, given that he, unlike us, has perfect rationality. However, I'm not sure how that would work. Anyone want to help me out? Would you agree with that in the first place, Alex?

Walter Van den Acker said...

Jensen

God knows in this case that ~p is possible, so believing that only p is possible would not be rational for Him.

Alexander R Pruss said...

Walter:

"I think open theists will probably say that God neither believes p is true nor that p is false"

I agree. That is what open theists will say. But they thus violate the very plausible principle that "a perfectly rational being believes anything there is overwhelming evidence for".

Sean Killackey said...

Does believing p imply that ~p is impossible? He's belive that it isn't the case, though, there is a non-zero probability it is the case, and hence it is at least logically possible.

Walter Van den Acker said...

Sean

I think it's important to define "believing". I "believe" that I am not a brain in a vat although there is ,as far as I am aware, no conclusive proof that I am not a brain in a vat.
But in order to say that it is 100 % certain that I am no brain in a vat, I must have such conclusive proof.
So, it would not be irrational to say I believe I am no brain in a vat.
But for an omniscient being, saying that he believes that p will occur amounts to saying that he is certain that p will occur, but in the case it is possible for ~p to occur, the omniscient being would believe a falsehood.

I guess it all comes down to whether knowledge of (every) future contingency is possible. If it's possible, then I agree that a being who doesn't know a future contingency does have an imperfection, and frankly, I don't see any reason why, if there are absolute truth values about future contigencies, an omniscient being would fail to know those contingencies. But I am no expert on open theism, so I am "open" to the possibility that open theists may have good reasons to think so.

This being said, I am not sure what Dr. Pruss means by truth-value open theism.