Robin Collins on WMAP and Infinite Universe
by BilboRobin Collins, professor of philosophy at Messiah College, who also holds a PhD. in physics, has written much about the fine-tuning argument, as well as other topics pertinent to science, religion, and ID. Recently I emailed him, asking about Bradley Monton's argument that based on the WMAP evidence, we should view the universe as infinite. He has allowed me to reprint his reply:
The WMAP evidence certainly is consistent with an infinite universe, but I would not say it is probably infinite. Two reasons. First, WMAP only shows that is very close to being flat, which still allows for the possibility that it has a small finite curvature, in which case it is finite. Second, a spatially flat universe does not imply an infinite universe.
For a flat universe, there is zero spatial curvature everywhere. The simplest geometrical object to which this corresponds to is a 3-dimensional flat hypersurface that extends to infinity. In this case, the universe is spatially infinite, with a similar mass-energy density to our own everywhere (given the starting assumptions of large-scale homogeneity and isotropy). Not all universes with spatially flat geometries are infinite in extent, however. In fact, there are ten other possibilities in which the hypersurface is locally flat but nonetheless closes back in on itself, thus forming a finite universe, the most familiar is the being the 3-Torus. One way of understanding how a finite universe is compatible with its being locally flat everywhere is to note that spatial curvature is a local notion defined by the intrinsic property of the space at every point. The overall topological structure – which determines whether the universe is finite or infinite – is a global notion that is constrained though usually not completely determined by the local curvature. [Footnote: When embed a two-dimensional closed surface—such as a torus-- in a three dimensional space, it looks curved, leading us to think that if a space is topologically closed, it must be curved. This reasoning is faulty: the embedding space can induce a curvature that is not the same as the intrinsic curvature as it is defined mathematically using the metric. (See Carroll, pp. ____).]
So perhaps we live in an infinite universe, but there are other ways of interpreting the evidence.
March 11th, 2010 at 7:46 am
Interesting discussion at Uncommon descent about Collins and fine tuning.
Comment by zykander — March 11, 2010 @ 7:46 am
March 11th, 2010 at 3:48 pm
I emailed Prof. Collins' response to Prof. Monton, who has allowed me to reprint his response:
Comment by Bilbo — March 11, 2010 @ 3:48 pm
March 11th, 2010 at 6:56 pm
Bilbo,
Monton did not say anything new and in fact responded to only one of Collins's points.
The latest WMAP measurements are consistent with the Universe being flat, but they are also consistent with the Universe having a slight curvature. Go here for a brief overview: Is the Universe Infinite? So the Universe still may have a positive curvature, have the topology a sphere and be finite.
As to the other point, a flat finite space, Monton's argument is that such topologies are "unnatural." Well, that's not a scientific argument, it's an aesthetic one.
Comment by olegt — March 11, 2010 @ 6:56 pm
March 11th, 2010 at 7:11 pm
Hi Oleg (and is it "Olegt" or Oleg?),
To be fair to Monton, he said he didn't think they were "physically realistic." And why am I defending the atheist while you are defending the Christian? Have I jumped to a parallel universe? How much is 2 + 2 here?
Comment by Bilbo — March 11, 2010 @ 7:11 pm
March 11th, 2010 at 8:13 pm
zykander,
I didnt read the comments, but the post is dead wrong. Barry Arrington writes:
There is all manner of problems with that statement. There is no way to say, a priori, what the probability of the constants might be, and whether it is large or small. The title of the post has to do with petard hoisting—and IDers, time and time again, hoist themselves royally by hitching themselves to the indemonstrable low probability argument.
The fine tuning argument, made correctly, is this: life is sensitive to the values of the constants.
It says nothing about probabilities—of which nothing can be said.
Let me repeat: the power of the fine-tuning argument has nothing to do with low probabilities.
In fact (I know, I have said this a million times), the IDers get it bass-ackwards.
Suppose we accept that life is sensitive to the values of the constants. (That is still the going-in position—in spite of Stenger claiming otherwise—all he did was some toy calculations, the old blowhard—you will note the deafening silence from physicists of all stripes, nobody except Stenger (and his non-scientific followers) claims that Stenger solved the fine-tuning problem). But even if you believe Stenger, for the sake of argument let's accept the fine-tuning premise that life is sensitive to the constants.
Consider then two "probability" scenarios:
1) There is no explanation for the constants, they are a low probability random draw
2) There is a theory, as yet undiscovered, that predicts the constants—so in fact they are high (unit) probability
The first scenario favors, at least superficially, the multiverse—because that in fact is exactly what it predicts.
The second possibility—the unit probability—is the one the IDers should champion because *IF* life is sensitive to the values of the constants AND the constants are high (unit) probability, you are then in the situation where habitability of the universe is built right into the fabric of spacetime. You’ll never get any closer to scientific support for design—not with all the vaporware specified-complexity calculations you can imagine.
But still the IDers pursue the low probability case—exactly the opposite of where they should be looking.
My guess is the same probably applies to biology too, that the inevitability of life (high probability) is a stronger case for design than the low probability, but there I am less certain. For the cosmological case I am sure—but the IDers have some bizarre hang-up with the meaningless, nonsensical, ad hoc so-called "universal probability bound" that causes them to be blind to the fact that they are looking at the wrong side of the probability range.
Comment by David Heddle — March 11, 2010 @ 8:13 pm
March 11th, 2010 at 8:48 pm
Hi David,
Interesting points you bring up on fine-tuning arguments, but I would prefer if we discuss them in another thread. I'll start working on it, and try to have it up by tomorrow.
Meanwhile, do you have an opinion on the WMAP data?
Comment by Bilbo — March 11, 2010 @ 8:48 pm
March 11th, 2010 at 8:55 pm
Bilbo,
I agree with Collins. (and I'd also say the WMAP data is one of the great scientific accomplishments of the last 25 years.)
Feel free to delete my fine-tuning comment.
Comment by David Heddle — March 11, 2010 @ 8:55 pm
March 11th, 2010 at 9:07 pm
Good heavens, no! With your permission, I'll probably just title the thread, "What the trouble-maker Heddle has to say about fine-tuning," then quote you completely, and then throw you to the sharks.
Comment by Bilbo — March 11, 2010 @ 9:07 pm
March 11th, 2010 at 10:12 pm
Bilbo,
Free free to use the comment however you like.
Comment by David Heddle — March 11, 2010 @ 10:12 pm
March 22nd, 2010 at 10:23 am
[...] an excellent example of the natural theology's resilience in David Heddle's take on the fine-tuning argument. Suppose physicists find some over-arching law that explains our the universe is so perfectly [...]
Pingback by The End of Intelligent Design Is Not Here - Thinking Christian — March 22, 2010 @ 10:23 am