Friday, April 14, 2006

PZ on Barrow

Now I didn't set out to write consecutive posts about PZ Myers, but here it is. It's true that his blog provides ample fodder, but as of late I've been ignoring it. Nevertheless here I go again…

I present for your consideration the Pharyngula post entitled Bilthering spititualists in which Professor Myers ridicules renowned physicist John Barrow, winner of the Templeton Prize, given for work in that most obvious of cross-disciplinary areas: science and religion. Myers begins with this recent and well-publicized exchange between Barrow and Myers's idol, Richard Dawkins:
When Selfish Gene author Richard Dawkins challenged physicist John Barrow on his formulation of the constants of nature at last summer's Templeton-Cambridge Journalism Fellowship lectures, Barrow laughed and said, "You have a problem with these ideas, Richard, because you're not really a scientist. You're a biologist."
I'm not going to say much about this because I wasn't there. But here is what I guess: It was a joke! One of those quips commonly offered in a seminar or colloquium. Was Dawkins upset, or did he chuckle? I don't know, but dollars to doughnuts it's the latter, otherwise there would have been widespread reporting of Dawkins's heated response. It would appear that Myers has adopted Dawkins's ethics, but not his sense of humor. After all, you might recall that Myers went into paroxysms of indignation over what cartoonist Scott Adams (of Dilbert fame) wrote about ID on his personal blog (See here for a reminder).

Myers claims that Barrow's shtick is the dreaded fine-tuning argument. He then dismisses Barrow's fine-tuning (anthropic principle) assertions with a refutation from novelist Douglas Adams:
…imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!'
(Myers goes ballistic over cartoonist Scott Adams's personal views, and then uses proofs from comic novelist Douglas Adams…there is something beautiful about the symmetry.)

Barrow, according to Myers, is little more than a glorified numerologist.

Let us follow PZ into never-never land and regard the scientific merit of Douglas Adams's retort. We note that it does not apply to the fine-tuning arguments of the universe, because those go well beyond stating that conditions are right for one type of life. Anthropic arguments and fine-tuing deal with the possibility for any life at all, of any type. We are not talking about the "minor" miracle that our planet supports large surface reservoirs of liquid water, but rather the insanely unexpected circumstance that there are any galaxies, stars, and elements heavier than Helium. You might be able to make a reasonable attempt to apply Douglas Adams's comment to arguments about the mediocrity of earth, or to human life, but definitely not to the universe as a whole.

That sets the stage for comments from the Myers faithful. Let's take a peek.

Also taking Barrow's comment about biologists oh-so-seriously, a Paul W comments:
Physics is unique among the sciences in that it studies the absolutely simplest, dumbest, most numerous and redundant things that exist. That is why it is "successful" in showing that things conform to very simple equations, to within many digits of precision---if they don't, you don't call it physics.

The defining characteristic of physics is that if you can't describe it that way, it isn't physics---it's chemistry, or meteorology, or geology, or or biology or something.

If it isn't incredibly simple, its not physics.
No other science can take this approach; only physics can. It's staked out the high ground. Or the low ground, with the lowest-hanging fruit.
And later he concludes:
When Darwin was in college, his friends advised him to give up on biology, which would never be much more than the "stamp collecting" of curiosities, without the kind of satisfying "deep" theory you get in physics. Physics was where the action was, they said.

But Darwin proved them wrong, and gave the best example of a scientific theory ever. Better than Newton's, even, because he wasn't gerrymandering away the incredible complexity of the natural world and focusing on the easiest problems. *(Deeper, too.)
Not only did Paul W take Barrow’s comments about biology at face value, which is silly enough, he responded with a variant of "my dad can beat up your dad."

Commenter JBL then makes the classic blunder:
We are fine-tuned to the universe, not the other way around. It's true that human life couldn't exist if the universe were built differently, but that is not at all the same as saying that life and conciousness couldn't exist at all. If protons and electrons all held together differently, everything would (of necessity) look so vastly different we probably can't imagine it. But that doesn't mean that the creation of concious life under such circumstances would be impossible -- merely that life which looks like us would be.
No JBL, that is wrong. Were it not for the fine tuning, the universe could easily have been only diffuse Hydrogen and Helium gas. As it stands, most of the universe does look like what it all could have been, and we see no signs of life in the near-vacuum of intergalactic space.

Someone named "poke" provided another inevitable and incorrect argument:
The constants of nature aren't "fine tuned" they're unexplained. This is just the usual "God of the gaps" argument.
Poke's premise that the constants are unexplained is correct. His conclusion, which I'm inferring, that if they were to be explained it would end the fine-tuning ID talking point, could not be more wrong.

Let us, for a moment, contrast cosmological ID to Susskind's String Landscape, which purports to explain the illusion of ID.

Susskind agrees that our constants are fine-tuned, in fact he provides some of the most persuasive presentations of fine-tuning. He says, however, that it is an illusion. There are 10500 universes, so we got the lucky draw. Notice the real implication: there is no possibility of explaining the constants in Susskind's theory—they are what they are.

Cosmological ID is compatible with "they are what they are" but does not demand it. Susskind's view implies that physics is hideous and anyone searching for an explanation for the constants is on a fool's errand—their research time would be better spent investigating cold fusion.

ID, while not requiring it, would be strengthened by the elegance of a fundamental theory explaining the constants—after all elegance is what we expect from God. We would then say: "God picked the theory" rather than the less pleasing "God picked the constants."

Poke's mistake is a common one, but the bottom line is that fine-tuning doesn't rest on the ignorance of the origin of the constants, it rests on the sensitivity of the universe to their values. It is not God of the gaps, but God of the details.

PaulC wrote:
I mean, fine tuning is a joke, right, everyone understands that the fine tuning "argument" is even sillier than "God planted the dinosaur bones" don't they?
Everybody except, it would seem, the large number of famous physicists, many of whom are atheists or agnostics (Krauss, Weinberg, Susskind, Hawkins,…), who are trying to explain it. To them, fine-tuning is not silly. To them it is a fascinating problem.

Torbjörn Larsson wrote, in what was probably the most cogent comment:
Finetuning means that parameters of a model must be adjusted precisely in order to agree with observations. It can often be explained by physical theories - inflation, endless inflation and supersymmetry for example.

The anthropic principle is ambigious.

There is the observational bias one - often people uses the fact that we exist here to make faulty hypotheses about the universe.
There is the tautological one - theories and parameter values must be consistent with our existence. That has somtimes been used to figure out parameter values, but they have later been replaced by calculations from theory.

String theory is currently a lot of mathematics and some theoretical physics. It has not been directly tested against experiments but makes contact with physics through its theoretical physics elements. This makes it more than prototheory IMO, contrary to what some says above it's a theory in its own right.

For example, in an endless inflation cosmology the landscape will be populated and the parameter values that maximise universe production in the endless inflation multiverse will be most common. This combined with the weak anthropic principle explains much and is compatible with the current value of the cosmological constant. If it's true it's the most parsimonious explanation in a sense, so we may not need to look further.
What fine-tuning parameters are explained by the theories he listed? Inflationary theories predict a flat universe, but they do not predict the value of the cosmological constant, nor do they say anything about the sensitivity of the universe to the values of the constants.

He also states that the anthropic principle sometimes predicts a parameter (true) that is later replaced by theory (false, as far as I know.) Weinberg predicted the value of the cosmological constant from an anthropic argument—but nobody has provided a theoretical basis for the value, and according to Susskind nobody ever will.

He also argues that string theory, even though it predicts nothing and has passed no test, gets a get-out-of-jail-free card. Although as unfalsifiable as ID it still gets to be called science because, well, it smells like science.

His comment about cosmic evolution, and "If it's true it's the most parsimonious explanation in a sense, so we may not need to look further." omits the detail that the theory is untestable.

No more PZ posts. Unless he writes something really unscientific and outrageous.

So I guess you better stay tuned.

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