Monday, March 23, 2009

Size Doesn't Matter (thank God), part 1

Contemporary western culture is dominated by the "conflict thesis", the claim that science and religion are at war, and that religion (or at least Christianity) is losing. The latter claims that human beings are the pinnacle of creation, but science has revealed that we are merely animals evolved from simpler forms of life, which in turn were just the product of matter and energy acting upon each other, all of which occupies an insignificant dot in an insignificant location in an infinite universe. Nietzsche illustrates this perspective well with the parable with which he opens his brilliant essay "On Truth and Lies in a Nonmoral Sense":

Once upon a time, in some out of the way corner of that universe which is dispersed into numberless twinkling solar systems, there was a star upon which clever beasts invented knowing. That was the most arrogant and mendacious minute of "world history," but nevertheless, it was only a minute. After nature had drawn a few breaths, the star cooled and congealed, and the clever beasts had to die.

To think we have any significance or value in light of this is essentially to stick your fingers in your ears, shake your head, and say, "La la la la, I can't hear you!"

One of the elements in this metanarrative is the incomprehensible vastness of the universe, only discovered in the modern scientific era, and the infinitesimal size of the earth in comparison. This renders absurd any suggestion that human beings, occupying only a speck of dust in a cosmic sandstorm, are special, showing (once again) that contemporary science has refuted Christianity. Or so the story goes.

This view is expressed well by Douglas Adams' Total Perspective Vortex and Monty Python's Galaxy Song. I was going to embed the latter, but since there are some, shall we say, improprieties therein, I decided to go with a different song that expresses this sentiment in a more family-friendly fashion.

Unfortunately (at least for some), there are multiple problems with the conflict thesis in general, and with the claim regarding the spatial insignificance of the earth in particular. Regarding the latter, everyone, of course, feels a sense of insignificance when faced with the vastness of the cosmos. This is universal, although some ages and cultures feel it more intensely than others. But before it can made into an argument against Christianity, several further questions must be answered. For example, why would something's value or importance be connected to its size? Does Christianity actually teach that humanity is the most important thing in the universe? If so, does it tie this to a belief that the universe is small and the earth the largest thing in it? Is it really only with modern science that we've discovered the universe's immensity, and thus the disparity between it and ourselves? In the remainder of this post I'll be addressing this last question from the side of science.

-- The impression that the universe dwarfs us is based on a sort of common sense view of measurement. But a couple of years ago James made a very important point about this issue. He compared human beings to the smallest and largest things in the universe; that is, he used the exponential scale which is precisely the standard of measurement which physicists employ. When this is done, it reveals that human beings are actually closer to the larger end of the scale than the smaller end. The smallest is the Planck length at 10-35 meters, and the largest is the universe itself, at about 1025 meters. "So comparing our absolute size to the smallest and biggest possible things in the universe, we are about three fifths of the way up the scale. In other words, we are of medium to large size using the exponential scale, the only scale that makes any sense in physics."

Of course, one could simply reject this standard of measurement as having any relevance to the issue. If one does, however, then one would have to reject the argument under discussion as well: for it depends on the claim that modern science has demonstrated our spatial insignificance. You cannot make this claim while rejecting the very method of measurement actually used by the sciences in question.

-- Another scientific point involves the Anthropic Principle. One of the characteristics I mentioned in this post is that the universe's mass density must be precisely what it is in order for life to be possible anywhere at any time in the universe's history. The mass density is the amount of matter in the universe. The velocity with which the matter and energy created in the Big Bang burst outward was precisely governed by the universe’s mass density, since the more mass there is, the more gravity would slow down the expansion, matter being what gravity acts upon. If the universe's mass density were different by one part in 1060, life could never exist at any place and at any time in the universe's history. In other words, if the universe was just a trillionth of a trillionth of a trillionth of a trillionth of a trillionth smaller or larger than it is -- an amount equal to "about a tenth part of a dime" according to the link above -- the universe’s velocity would either have overpowered gravity, or it would have been overpowered by gravity. The first case would have prevented the matter from being collected into stars and galaxies. The second case would have resulted in the universe collapsing back in on itself. Either way, life would have been impossible anywhere at any time in the universe. So in order for life to be possible on our dust speck of a planet, the universe must be precisely the size that it is.

Of course, some people will insist that this is not enough. Just because every piece of matter had some relevance to the universe's initial expansion, it does not have any connection to our existence now -- and this calls into question any view that sets up the earth and humanity as significant. In other words, unless every rock, planet, star, and galaxy in the universe is always and only there for our benefit, Christianity (somehow) cannot be true.

But what exactly is being asked here? Given the necessary fine-tuning of the universe's mass density, the matter making up these rocks, planets, stars, and galaxies had to be there. To ask why they're still there is to ask why God didn't destroy them once they served their initial purpose. In other words, it is to expect God to destroy the evidence of what he has done. This is problematic on several levels, not least of which is that if God did do this, the same people who raise this objection would obviously be pointing to the lack of evidence for God. So it seems that no matter what he does -- whether he keeps the matter there as a testimony to his actions or whether he destroys it once it has served this purpose -- they will use it as an argument against his existence. I may come back to this in future installments.

-- Alexandre Koyré argues in From the Closed World to the Infinite Universe that there is an element to modern cosmology that is lacking in its ancient and medieval counterparts. Regardless of how big they thought the universe to be, they clearly believed it to be finite. But modern science has, according to Koyré, demonstrated that the universe is infinite. The reason this is significant is because moving from one finite size to another is not the same as moving from a finite size to an infinite one. Regardless of how large the ancients and medievals conceived the universe to be, there is a difference in kind involved here, and this is the significant aspect of modern cosmology that refutes the ancient and medieval cosmology. "Let us not forget, moreover, that, by comparison with the infinite, the world of Copernicus is by no means greater than that of mediaeval astronomy; they are both as nothing, because inter finitum et infinitum non est proportio. We do not approach the infinite universe by increasing the dimension of our world. We may make it as large as we want: that does not bring us any nearer to it."

I will not contest here Koyré's claim that an infinite universe is a different type of thing than a finite one, and as such, would represent a complete change of our view of the cosmos as well as ourselves. On this score, C. S. Lewis agrees: in The Discarded Image (a text to which I'll be returning) he argues that there is a radical difference between believing in a distant horizon and believing in no horizon at all.

Hence to look out on the night sky with modern eyes is like looking out over a sea that fades away into mist, or looking about one in a trackless forest -- trees forever and no horizon. To look up at the towering medieval universe is much more like looking at a great building. The 'space' of modern astronomy may arouse terror, or bewilderment or vague reverie; the spheres of the old present us with an object in which the mind can rest, overwhelming in its greatness but satisfying in its harmony. That is the sense in which our universe is romantic, and theirs was classical.

This explains why all sense of the pathless, the baffling, and the utterly alien -- all agoraphobia -- is so markedly absent from medieval poetry when it leads us, as so often, into the sky. Dante, whose theme might have been expected to invite it, never strikes that note. The meanest modern writer of science-fiction can, in that department, do more for you than he. Pascal's terror at le silence éternel de ces espaces infinis never entered his mind. He is like a man being conducted through an immense cathedral, not like one lost in a shoreless sea.

Perhaps, then, one could argue that since an infinite universe presents us with an object in which the mind cannot rest, this sense of "agoraphobia" that it produces entails a greater sense of insignificance than any finite universe could convey; and hence a greater assault on humanity's dignity. However, Lewis argues to the contrary: an infinite universe would have no absolute standard of measurement, only relative standards. But a finite universe would have both absolute and relative standards of measurement.

The really important difference is that the medieval universe, while unimaginably large, was also unambiguously finite. And one unexpected result of this is to make the smallness of Earth more vividly felt. In our [infinite] universe she is small, no doubt; but so are the galaxies, so is everything -- and so what? But in theirs there was an absolute standard of comparison. ... The word 'small' as applied to Earth thus takes on a far more absolute significance.

Koyré argues that modern science requires a complete overhaul of our view of the cosmos and our place in it because we have discovered that the universe is infinite. The irony is that, even before Koyré wrote this, Einstein's relativity equations and Edwin Hubble's observations of the expansion of the universe indicated something different. Today Big Bang cosmology has established that the universe is spatially and temporally finite. It began to exist a particular time ago, and has a finite size. In this sense at least, the ancient/medieval cosmology has been exonerated. Whether Lewis is right to describe it as "unimaginably large" will be the subject of the next installment.

Update (11 Aug): (see also part 2 and part 3)

(cross-posted at Quodlibeta)


jacob longshore said...

You could add that Frederick Turner makes an interesting point: Earth may not be the biggest planet and all, but more happens here than anyplace we know (from The Culture of Hope, page somethin'-or-other). Or is something of this already in part 2?

Leonhard said...

Just a minor quibble, two years too late but still Big Bang cosmology does not show that the universe is spatially finite. The jury will probably be permanently out on that one. Short story: The best measurements of the cosmic background radiation shows us that spacetime is flat on the largest scales. If spacetime is finite (closed) then it must be so large that from our vantage point it appears flat even though it has a positive curvature.

That doesn't change that our universe must from a state of (near) infinite density and temperature some finite amount of time in the past.

Jim S. said...

I've never heard that. Interesting.