Monday, October 31, 2011

Having forced myself to slog through Swinburne, I thought I could give the whole area of arguments for God a rest. Swinburne admits that there are no valid deductive proofs of God's existence, and all his "good inductive arguments" for God seem pretty weak to me. But I keep running across atheists who claim either  that there are reasonable arguments for God, or that the usual arguments for naturalism fail, or both. For instance, here's a curious article in Philo by atheist philosopher Quentin Smith. I like and respect Smith: he has published some very cogent counter-arguments to the arguments of William Lane Craig and other theists. So when he says that naturalists are naturalists for all the wrong reasons, I have an uncomfortable feeling that he's probably right.

Oddly, though, he doesn't (in this article) tell us what the wrong argument for naturalism is, nor what he considers the right argument. This he leaves to "other papers and books."

One book that is often mentioned favorably (by Smith, among others) is Arguing About Gods, by Graham Oppy. According to the Amazon reviews, Oppy - an atheist - concludes that neither side has arguments sufficient to convince the other.

To me, the naturalist arguments seem clearly superior. My questions are, what reasons do theists have to remain theists (it seems to me they don't have any), and why aren't the naturalist arguments strong enough to be convincing (as it seems to me they are)?

I guess I have to do some more reading....

Friday, October 21, 2011

Smart People Who Say Stupid Things (Again)

Thanks to a post at TheSecular Outpost, I came across an article by Robin Collins on fine tuning, that explicitly discusses the procedure of "subtracting out" the knowledge that our universe supports life, which I mentioned in this previous post. It provides another example of how a smart person can say very stupid things when talking outside of their sphere of expertise.

Collins is discussing the fine tuning of the gravitational force relative to the electromagnetic force. Having argued for the life-allowing range of the gravitational constant, G, he goes on to attempt to determine the relevant comparison range of "allowable" values. He argues:
Given that the very idea of a constant of physics only makes sense within a set of laws of nature, and a set
of laws only make sense as instantiated in some universe, it makes no sense to talk about varying a constant
beyond its universe-permitting range. In other words, possible law structures can only exist if there is a
possible universe to instantiate them.

OK, let's suppose that's a reasonable approach. What then is the universe-permitting range of G values? Collins writes:

Although it is unclear exactly what the upper
bound of the "universe-permitting" strength of the gravitational force is, certainly if gravity were, for
example, a factor of 10^100 larger, a viable universe would be impossible: the gravitational attraction that a
single particle exerted on itself would result in a black-hole.
 Um. There's so much wrong in this sentence that it's hard to know where to start.

1) In neither Newton's nor Einstein's theory of gravity do we include the gravitational attraction that a
single particle exerts on itself in the calculation. We find instead the force that all other masses exert on our particle.

2) A single point particle, all by itself, is a black hole regardless of the strength of gravity.

3) A black hole solution is a valid possible universe in General Relativity. A bit later Collins writes:
Does our "black hole
universe" consisting of no-space time qualify [as a permissible universe]?

Sorry, but a black hole is not a solution consisting of "no space-time." It is exactly the opposite: a solution describing the space-time around a mass. And black hole solutions are possible no matter the value of G.

4) Expanding and re-contracting universes are possible regardless of the value of G. The right-hand side of Einstein's GR equations is G times the energy-momentum tensor. Thus, increasing G is the same as increasing the density of energy-momentum in the universe. Standard cosmological models (like the FLRW models) are still valid, no matter how large we make the density. Admittedly, the larger you make the density, the sooner the universe will re-collapse. But that's still a possible universe.

5) Empty universes, where the right-hand side of Einstein's equation is equal to zero, are still possible for any value of G. Collins asks whether empty universes count, but doesn't give any answer. He just ignores the issue. But it's clearly important for his project of determining the range of G that permits universes: if we include empty universes, then all possible values of G result in possible universes.

Collins seems to be a very smart guy, judging by the earlier parts of this paper. Yet he doesn't seem to have bothered to understand the physics he's employing before writing his article. Didn't he bother to check with an actual physicist? Or maybe he did, but got bad advice? (He doesn't acknowledge any assistance in the paper.)

At any rate, it seems it's not just us physicists who assume all other fields are easy.

Wednesday, October 19, 2011

Thursday, October 13, 2011

Fine Tuning Supports Naturalism

Garren's comments on the previous post got me thinking more about fine tuning. There are lots of reasons to dislike fine tuning arguments for God, but it occurred to me that we can turn the fine tuning argument around and show how it actually supports naturalism, not theism. Let me explain.

The usual fine tuning argument goes like this: Our universe is governed by natural laws that involve certain numerical parameters - the cosmological constant, the strength of the nuclear force, etc. Some of these parameters must lie in a very narrow range in order for life to exist:

PU = Possible Universes
FTU = Fine-Tuned Universes

So, given a naturalistic hypothesis (N) and general background knowledge (K), the probability of a fine-tuned universe is small:

P(FTU|N&K) = Area(FTU)/Area(PU)  << 1

On the other hand, given the theistic hypothesis (T), we would expect the universe to be suitable for life: P(FTU|T&K) is not small, or at least not as small as P(FTU|N&K).

One of the (many) problems with this argument is that we can't assert that the probability is given by the ratio of the areas without making many additional assumptions: that the values of parameters 1 and 2 are randomly chosen from the space of all parameters, for instance. But that's not the objection I want to pursue. Rather, I want to point out that the probability envisioned in the fine tuning argument is a sort of prior probability that ignores some of our background information: namely, the fact that life actually exists. That is, we have to take (K) to mean "general background knowledge not including the knowledge that life exists."

But we actually do know that life exists (L), and it is perfectly legitimate to include this knowledge along with our other background knowledge. If we add this knowledge back in, then trivially P(FTU|N&K&L) = 1: under the naturalistic hypothesis, the only way that life can exist is for the universe to have parameters that allow the existence of life.

But that is not true if God exists! Indeed, under theism, there is no reason to expect that the universe will be fine-tuned.

Remember that God is, by hypothesis, omnipotent. That means that God could  have caused life to arise by miraculous means, even in a universe that was not fine-tuned. Say, for example, that the universe had a value of the cosmological constant that caused it to expand too fast for galaxies to form. God could have prevented a galaxy-sized region from expanding in order to allow our Milky Way to form. Or God could have inserted a pre-made galaxy. Or he could have inserted an additional force that operated only within our galaxy and that countered the effects of the expansion. Or any number of other possibilities, because God can do anything.

So, under theism, the diagram looks like this:

That is, the probability of a fine-tuned universe under the theistic hypothesis is:

P(FTU|N&K&L) = Area(FTU)/Area(PU)  << 1

Conclusion: given that we know that life exists, the probability of discovering we are living in a universe with parameters fine-tuned for life is much higher under the naturalistic hypothesis than under the theistic hypothesis.

Thursday, October 6, 2011

What Kind of Atheist Are You?

Roman Catholic philosopher Edward Feser asks what attitudes we atheists take toward religion. Usefully, he separates out the theoretical and practical sides of religion.

As far as the theoretical side - that is, the questions of religious beliefs - he sees three types of attitudes the non-religious might take:

1. Religious belief has no serious intellectual content at all.  It is and always has been little more than superstition, the arguments offered in its defense have always been feeble rationalizations, and its claims are easily refuted.

2. Religious belief does have serious intellectual content, has been developed in interesting and sophisticated ways by philosophers and theologians, and was defensible given the scientific and philosophical knowledge available to previous generations.  But advances in science and philosophy have now more or less decisively refuted it.  Though we can respect the intelligence of an Aquinas or a Maimonides, we can no longer take their views seriously as live options.

3. Religious belief is still intellectually defensible today, but not as defensible as atheism.  An intelligent and well-informed person could be persuaded by the arguments presented by the most sophisticated contemporary proponents of a religion, but the arguments of atheists are at the end of the day more plausible.

And as far as religious practice is concerned: rituals, morality, and (I would add) community, he likewise sees three possibilities:

A. Religious practice is mostly or entirely contemptible and something we would all be well rid of.  The ritual side of religion is just crude and pointless superstition.  Religious morality, where it differs from secular morality, is sheer bigotry.  Even where certain moral principles associated with a particular religion have value, their association with the religion is merely an accident of history.  Moreover, such principles tend to be distorted by the religious context.  They certainly do not in any way depend on religion for their justification.

B. Religious practice has a certain admirable gravitas and it is possible that its ritual and moral aspects fulfill a real human need for some people.  We can treat it respectfully, the way an anthropologist might treat the practices of a culture he is studying.  But it does not fulfill any universal human need, and the most intelligent, well educated, and morally sophisticated human beings certainly have no need for it.  

C. Religious practice fulfills a truly universal or nearly universal human need, but unfortunately it has no rational foundation and its metaphysical presuppositions are probably false.  This is a tragedy, for the loss of religious belief will make human life shallower and in other ways leave a gaping void in our lives which cannot plausibly be filled by anything else.  It may even have grave social consequences.  But it is something we must find a way to live with, for atheism is intellectually unavoidable.

Feser plausibly sees P.Z. Myers and Jerry Coyne as A1 type atheists. But, he says, to hold this position, one must
...think it plausible that the greatest minds of entire civilizations -- Augustine, Aquinas, Maimonides, Avicenna, Averroes, Lao Tzu, Confucius, Mencius, Buddha, Adi Shankara, Ramanuja, et al. -- had for millennia been defending theoretical and practical positions that were not merely mistaken but were in fact nothing more than sheer bigotry and superstition...

 On the theoretical side, I would put myself solidly in category 2. I can't imagine how intelligent, educated people today still cling to religion. Actually, I can imagine it, because I used to be one of them. But I find it hard to believe that after looking at all the arguments and evaluating them honestly, someone would conclude that, yes, an invisible person in the sky is more plausible than not.

On the practical question, I place myself somewhere between B and C. I think religion does address fundamental human needs, but I think it does it very imperfectly, and I don't see why we need to introduce supernatural entities to address those needs. (Some of the "greatest minds" Feser mentions didn't see a need for supernatural entities, either: Lao Tze and Buddha, for instance.)

Also, I don't think it's a tragedy that religion is false - I think we can get along fine without it. Maybe even better - but we will have to work on replacing religious institutions with non-religious institutions that address those same needs. We don't have those structures yet.

(Cross posted on Think Atheist.) 

Sunday, October 2, 2011

Should Atheists Read Aquinas?

Reading some of the altercations between Jerry Coyne and Edward Feser has got me wondering: when do we need to delve deeply into the other side's arguments, and when is it OK (if ever) to give a simple answer and move on? Life is short, and I don't want to spend the rest of it reading a bunch of clap-trap just in order to debunk it. On the other hand, as True Skeptics™ we want a rational basis for what we believe - we don't want to dismiss some idea just because it interferes with our preconceived worldview. So we feel a certain obligation to look into the other side's arguments in detail. And if we fail to do our due diligence, people like Feser and William Lane Craig end up running circles around us

So, here are some guidelines to help decide when enough is enough.

Know your audience; know your argument. It is, it seems to me, perfectly legitimate to address simple arguments for God with simple answers. Most believers don't believe because of some philosophically sophisticated argument of Aquinas or Craig. Rather, they are thinking something like, "Everything had to come from something." To this, it is enough to reply, "No, it didn't," or "Saying it came from God just pushes the problem back one step."

So it seems fine to write books or blogs that address the popular arguments for God while leaving out the philosophically sophisticated ones. If people like Feser complain about this, one need only point out that there are philosophically sophisticated answers already out there for those sophisticated arguments, and anyone who cares to do so can read up on them.

On the other hand, if you are addressing a particular argument for God, you had better understand the different versions of that argument, and the responses to them, and the responses to the responses, or you will end up with the taste of shoe leather in your mouth. It makes no sense to invent your own version of the Cosmological Argument and then proceed to knock that down - that's a classic straw man fallacy.

Triangulate. If prominent experts on the other side have abandoned a particular line of argument, it seems legitimate to ignore that line. If someone tries to argue that humans and dinosaurs lived at the same time because of the Paluxy footprints, I only need to point out that not even the Institute for Creation Research defends the Paluxy claim any more. Similarly, given the fact that theistic philosophers like Richard Swinburne and Alvin Plantinga have agreed that there are no valid deductive proofs of God's existence, I don't feel the need to pursue those any more. If Feser thinks he has rehabilitated Aquinas's cosmological proof and that all atheists need to read his book to find out how, well, fine: when he has convinced his fellow theists that he's done so, then I might look into it. Until then, I'm not going to waste my time.

Remember that the courtiers are sometimes right. PZ Myers has identified the "Courtier's Reply." In brief, the term refers to those who respond to the cry "The Emperor has no clothes!" with learned sneers, "He has apparently not read the detailed discourses of Count Roderigo of Seville on the exquisite and exotic leathers of the Emperor's boots..." and so forth.

But here's the thing: the courtiers are sometimes right. There are many highly educated and highly intelligent believers, and they have thought long and hard about their positions, and can defend them ably. When you run up against one of these, you should either shut your mouth or do the hard work of learning the real issues and responding to them. Giving a simplistic answer to a complex question is worse than giving none at all (see Know your audience above).

Atheists should respect the intelligence of their opponents. We think we have the better arguments. If we do, we should welcome the engagement with the best and the brightest among the theists.