Tuesday, February 1, 2011

Sceptical non-theism

Sceptical theists respond to the problem of evil by, very roughly, telling us that we can't say what kinds of worlds God is more likely to create. This is a very rough formulation, and perhaps not entirely fair, but I think it is defensible. After all, if we have no reason to think that the values we know are representative of the larger realm of value, then we are unable to say what kinds of worlds a being whose actions are entirely guided by correct value considerations is likely to create.

I defined sceptical theism in such a way that it does not entail theism. Thus, an atheist could be a sceptical theist, and in fact it's fair to say that Anthony Flew, before he became a theist and while he was pressing the claim that the God hypothesis has no empirical consequences, was committed to something like sceptical theism.

It seems likely—though this can be questioned—that the conjunction of theism with sceptical theism commits one to wide-spread scepticism. If we don't know what sorts of worlds God is more likely to create, and we think this world is one that God created, we really shouldn't trust induction, etc. This is good reason for theists not to opt for sceptical theism.

But there is another position to be considered: sceptical non-theism. Sceptical non-theism tells us that we can't say what kinds of worlds are more likely to exist if God doesn't exist.

Just as sceptical theism does not imply theism, so too sceptical non-theism does not imply non-theism. If one is both a non-theist and a sceptical non-theist, then one is pushed towards more general scepticism. But if one is a theist and a sceptical non-theist, then one can resist scepticism, it seems. So sceptical non-theism doesn't carry the danger to the theist that sceptical theism does. Moreover, sceptical non-theism answers the problem of evil just as well as sceptical theism does. The theist who is a sceptical non-theist can say: "Granted, it sure looks like these horrendous evils are very unlikely given theism. I grant you that! But I have no reason to think that they are any more likely given non-theism. And in order for these evils to be an argument against theism, they would have to be more likely given non-theism."

Furthermore, sceptical non-theism is at least as well motivated as sceptical theism. Consider the fact that non-theism is a disjunction of a large number of very different views, including: polytheism, kakotheism, pantheism and naturalism (I am tempted to include "open theism" here, too). Naturalism in turn is a disjunction of a large number of very different views, since any logically coherent all-encompassing physical theory gives rise to a version of naturalism. On any one of the disjuncts, it's hard to figure out what sort of world would likely exist. And it's hard to figure out which disjunct is more likely than which. Hence, figuring out what world would be more likely to exist if non-theism held seems to be an insuperable task. This remains true even if we replace "non-theism" with "naturalism".

I do not endorse sceptical non-theism. But I do endorse the thesis that it is a better move for theists than sceptical theism.


enigMan said...

Fifth para, last sentence, last word of first half should be 'theism', no? (Also, I wonder why you're tempted to count open theism as a non-theism, or was that a joke?)

enigMan said...

Also, I don't see how sceptical non-theism is as good a reply to the problem of evil. The problem of evil is that evil seems to be unlikely given theism. It's no reply to say that it's not obviously likely given non-theism. To go such a route you would have to say why it seems to be unlikely given non-theism.

Alexander R Pruss said...

I fixed the typo, thanks.

As to the response to the problem of evil, that E is very unlikely on a hypothesis H is not by itself evidence against H. For instance, let n be the exact number of protons I have in my body. This is some integer with a large number of digits. Let E be the event of my having exactly that many protons in my body.

Then, P(E|quantum mechanics) is extremely small. But that is not evidence against quantum mechanics. Why? Because P(E|not quantum mechanics) is also extremely small.

In standard Bayesian settings, for E to be evidence against H, we must have good reason to think that P(E|~H) is larger than P(E|H). So if P(E|non-theism) is completely unknown, then it is completely unknown whether P(E|non-theism)>P(E|theism).

Alexander R Pruss said...

Here's another way to put this. The correct way to measure the amount of evidence that E gives to a hypothesis H is P(E|H)/P(E|~H). (This is controversial, but see my post on the measure of confirmation for an argument.) The sceptical theist says this ratio is unknown because the numerator is unknown. I am proposing (not simpliciter, but as an alternative to sceptical theism) that it is better to say that it is unknown because its denominator is unknown.

enigMan said...

I see, thanks.

Anonymous said...

Is this the argument: granted the probability of evil on theism is low, but the probability of evil on any sort of non-theism is inscrutable, so evil is not a good argument against theism? If so, shouldn't we be agnostics, at least on the basis of this argument alone? We should say, "I don't claim to know that there is no such being as God, but I know this much: evil counts against God, so we should at least be agnostics. I think many people DO think like that.

The arg. from evil is said to be an undercutting defeater for theism. It allegedly leaves us with agnosticism. Skeptical theism (which I think should be called "humble theism," unless that is too self-congratulatory) is an undercutting defeater for the arg. from evil. It says we have not been moved to agnosticism. But I don't see how saying that the probability of evil on non-theism is inscrutable could be an undercutting defeater for the arg. from evil.

I also don't see why humble theism should lead to widespread skepticism. Seems to me we only need to say that we don't know EVERYTHING (moral value included) but not that we don't know ANYTHING. The "humble response" undercuts the arg. from evil without undercutting the knowledge that we have.

Alexander R Pruss said...

That the probability of E on H is very low is not by itself a reason to be an agnostic about H. For instance, the probability of E on H may be very low, but may be even lower on ~H, and so E might in the end be evidence for H.

So, if I don't know anything about the probability of E on ~H, I don't know if E is evidence for or against H. This means that I should suspend judgment on whether E supports or harms H. It does not mean that I should suspend judgment on H.

Compare this. Let H be evolutionary theory. Let E be the existence of species of 14-legged inverterbrates that are about 50cm in length as adults. I have no idea if in the final analysis E would favor or disfavors H. To know whether it favors or disfavors it, I'd have to be able to estimate P(E|H), which I suppose is fairly low, and P(E|~H), which I have no idea how to estimate (I suppose one of the alternatives to H is that God designs everything directly; but what is the probability that God would make such critters? I have no idea!) I should thus suspend judgment about whether E supports H. But I have no need to suspend judgment on H. The existence of giant isopods does not give me reason to be agnostic about evolutionary theory.

enigMan said...

Thanks again, your explanations are v. nice; but my original worry remains. I think my problem was my use of 'unlikely' in "evil seems to be unlikely given theism" (following your theist's "these horrendous evils are very unlikely given theism"). I see now how sceptical non-theism answers surprisingly well such evidential problems of evil. But perhaps the problem of evil is not really so evidential (whilst also not being merely logical).

The problem seems to be more like something that follows from the question of what Jesus would do if he saw an innocent child dying agonisingly slowly. If he would save the child, then we might wonder how God can be like Jesus and omnipotent (the problem of evil). We can say that we don't know what Jesus would do (although then we may find it hard to be Christians). But to say that we don't know how likely such deaths would be were there no God would seem to miss the point.

Josh said...

If we let ‘H’ be the proposition that a lot of horrendous evil exists, ‘T’ the hypothesis of theism, ‘N’ the hypothesis of naturalism (the view that there are no supernatural agents), and ‘b’ our background knowledge, we may construct an argument from evil against T as follows:

(1) P(N/b) is at least as high as P(T/b)
(2) P(H/N & b) is much higher than P(H/T & b)
(3) Therefore, other evidence held equal, T is probably false.

Your objection seems to be that P(H/N & b) is inscrutable, and so we not in the position to know that premise (2) is true.

Whether this is correct or not, however, seems to depend on what is included in the background knowledge. If the background knowledge includes only tautologies and things known by rational intuition, then perhaps P(H/N & b) is inscrutable. But suppose that we only abstract H from our background knowledge and leave the rest intact insofar as is possible. That may leave enough knowledge of the physical world to enable us to rule out many of the logically coherent physical theories you mentioned. In that case, then, we are conjoining N with a fairly rich understanding of the way the world is. It could then be argued that N conjoined with this rich stock of background knowledge predicts H far better than T predicts H when conjoined with the background knowledge. That kind of argument seems less vulnerable to your concerns.

Alexander R Pruss said...


That's a very promising response. But I worry that there will be objectionable gerrymandering in selecting what one includes in the background. If one includes enough in the background, then the background will predict horrendous evils whether it is conjoined with T or with N. And if one includes very little in the background, then P(H|N&b) will still be beyond our ken.

One problem in the vicinity is maintaining the claim that P(N|b) is close to P(T|b). For instance, we either do or do not include in b the information that there is consciousness. Now, plausibly, P(consciousness|N) is low or inscrutable, while P(consciousness|T)=1 (God is by conscious). Suppose we do include in b the information that there is consciousness. Then P(N|b) will be low or inscrutable. Suppose we don't include in b the information that there are conscious beings. Then, the probability of consciousness on N&b will be low or inscrutable, and hence the probability of H on N will be low or inscrutable, since H seems to entail that there is consciousness. (You can have evils without consciousness, but probably you can't have horrendous evils without consciousness.)

Josh said...

Dr. Pruss,

Thanks for the response.

Suppose we include in b the fact that consciousness exists. Call this fact ‘c.’ You point out that while P(c/T) = 1, P(c/N) is either low or inscrutable. Let us suppose that P(c/N) is low. It follows that P(c/T) is much greater than P(c/N). The fact that c, therefore, is evidence for T over N.

However, c is not the only fact included in b, if we are simply abstracting H from our background knowledge. The following is also a fact:

d: consciousness depends heavily on the brain.

We know the following is the case:

P(c & d/N) = P(c/N) x P(d/N & c)

P(c & d/T) = P(c/T) x P(d/T & c)

Now I grant that P(c/T) is much higher than P(c/N). However, it could be argued that P(d/N & c) is much higher than P(d/T & c). Suppose that argument were a good argument. Then it would seem that P(c & d/N) is roughly equal to P(c & d/T), despite the fact that T predicts c better than N does.

Attending to facts other than c that are included in our background knowledge may show that P(N/b) really is at least as high as P(T/b). This may be the case even if T predicts c a lot better than N does. So I don’t think it can be shown that it is false that P(N/b) is at least as high as P(T/b) simply by pointing out that T predicts c better than N does. Isn’t it the case that one must consider all the facts included in the background knowledge? But perhaps I’ve misconstrued your response.

Alexander R Pruss said...

By the "brain", I assume you mean "a physical part"? After all, the probability that brains--a specific kind of organ in earthly chordates--would exist given naturalism is probably inscrutable.

Is it likely on naturalism that consciousness would depend on a physical part? I don't know. It depends what exactly naturalism says. Maybe it is logically possible to have things that are natural--for instance, that obey natural laws--but completely non-physical. I suppose, though, one can define naturalism in such a way that it entails physicalism, and then naturalism does entail that if there is consciousness, the consciousness depends on a physical part.

I suppose now we have to compare the probability that there is consciousness and it depends on a physical part given naturalism with the probability that there is consciousness and it depends on a physical part given theism. That's going to be tough.

Alexander R Pruss said...

If we start including in b the fact that consciousness depends on a body part, and a lot of stuff about laws of nature, then now the existence of horrendous evils is apt to become likely given theism.

Josh said...

I also worry that the background knowledge may pose problems for arguments from evil. As you indicate, if we include a lot in the background knowledge, then suffering will not be terribly surprising given T and the background knowledge. If we don’t include a lot in the background knowledge, then it’s not clear that we can assign a value or a range to P(H/N & b). Either way, it seems that the argument won’t work.

This is a bit of a tangent, but I wonder if your remarks pose a problem for design arguments. Suppose that we find an arrangement of stars which spell the message “God exists and loves you all.” Call the fact that our universe contains such a message ‘S.’ We could argue as follows:

(1) P(T/b) is at least as high as P(N/b).
(2) P(S/T & b) is much greater than P(S/N & b)
(3) So, other evidence held equal, N is probably false.

Suppose we employ a skeptical non-theism strategy. The naturalist might argue that P(S/N & b) is inscrutable on the grounds that, for all we know, there are an infinity of universes that vary randomly with respect to physical laws. Given bare naturalism, one just is not in the position to argue that it is unlikely that there would be an infinity of such universes. But if there are, then S is not strong evidence against N.

I wonder if skeptical non-theism can undermine the argument from evil only by also undermining design arguments as well.

Alexander R Pruss said...

"I wonder if skeptical non-theism can undermine the argument from evil only by also undermining design arguments as well."

Yes. That's why I don't endorse skeptical non-theism. I only endorse the claim that it's better than skeptical theism. Skeptical theism not only undermines design arguments, but when conjoined with theism runs a serious danger of undermining a lot of ordinary knowledge. Skeptical non-theism undermines design arguments, but I think its nasty skeptical implications end there.

Crude said...


Re: Skeptical non-theism undermining design arguments, you say...

Yes. That's why I don't endorse skeptical non-theism. I only endorse the claim that it's better than skeptical theism.

There's something I wonder about this.

At least for some design arguments, don't they gain their force by what known, existing intelligent agents are capable of? In other words, it's demonstrable that human beings are capable of creating X, X appears in nature, ergo we should infer* design.

Now, the naturalist may respond "But maybe X could have been created by an unguided, purposeless 'force' too with no intelligence behind it!" But it seems to me the combination of skeptical non-theism and.. I guess it would be called a mix of a priori and a posteriori data would result in a broad theism being ahead of non-theism.

One way to put it would be this: We have undeniable knowledge that at least one intelligent agent exists. We also have undeniable knowledge of what these intelligent agents are capable of in practice and in principle. In both practice and principle an intelligent agent can be explanatory for all features of our known universe. An IA being explanatory for all features of our known universe would be some form of theism. We have no undeniable knowledge of the existence of purely "naturalistic" forces, operations, or results (meaning, f, o, or r that take place utterly without an IA being behind them in any way). Therefore on skeptical non-theism, some form of theism is preferred.

Sorry if that's sloppy. Amateur here.

(*Note: I'm not talking here about Intelligent Design strictly, since I think ID is defined by some conclusions and assumptions unrelated to this topic.)