But to take this as an ontological statement about something's actual importance is incredibly naïve. Just because bigger sometimes seems better, it's absurd to think that there is a significant correlation between size and value. What exactly is it about size that would bestow value anyway? Why would a smaller thing automatically be less important than a bigger thing? While it's true that the immense size of the universe can make us feel insignificant, this is a psychological fact about us, not a scientific fact about the universe. For people who accuse others of simple-mindedness, those who argue that the universe's size demonstrates our unimportance are remarkably simple minded themselves.
C. S. Lewis puts this so much better than I ever could that I'll just refer you to the 7th chapter of Miracles:
There is no doubt that we all feel the incongruity of supposing, say, that the planet Earth might be more important than the Great Nebula in Andromeda. On the other hand, we are all equally certain that only a lunatic would think a man six-feet high necessarily more important than a man five-feet high, or a horse necessarily more important than a man, or a man's legs than his brain. In other words this supposed ratio of size to importance feels plausible only when one of the sizes involved is very great. And that betrays the true basis of this type of thought. When a relation is perceived by Reason, it is perceived to hold good universally. If our Reason told us that size was proportional to importance, the small differences in size would be accompanied by small differences in importance just as surely as great differences in size were accompanied by great differences in importance. Your six-foot man would have to be slightly more valuable than the man of five feet, and your leg slightly more important than your brain -- which everyone knows to be nonsense. The conclusion is inevitable: the importance we attach to great differences of size is an affair not of reason but of emotion -- of that peculiar emotion which superiorities in size begin to produce in us only after a certain point of absolute size has been reached.
We are inveterate poets. When a quantity is very great we cease to regard it as a mere quantity. Our imaginations awake. Instead of mere quantity, we now have a quality -- the Sublime. But for this, the merely arithmetical greatness of the Galaxy would be no more impressive than the figures in an account book. To a mind which did not share our emotions and lacked our imaginative energies, the argument against Christianity from the size of the universe would be simply unintelligible. It is therefore from ourselves that the material universe derives its power to overawe us. Men of sensibility look up on the night sky with awe: brutal and stupid men do not. When the silence of the eternal spaces terrified Pascal, it was Pascal's own greatness that enabled them to do so; to be frightened by the bigness of the nebulæ is, almost literally, to be frightened at our own shadow. For light years and geological periods are mere arithmetic until the shadow of man, the poet, the maker of myths, falls upon them. As a Christian I do not say we are wrong to tremble at that shadow, for I believe it to be the shadow of an image of God. But if the vastness of Nature ever threatens to overcrow our spirits, we must remember that it is only Nature spiritualised by human imagination which does so. This suggests a possible answer to the question raised a few pages ago -- why the size of the universe, known for centuries, should first in modern times become an argument against Christianity. Has it perhaps done so because in modern times the imagination has become more sensitive to bigness? From this point of view the argument from size might almost be regarded as a by-product of the Romantic Movement in poetry. In addition to the absolute increase of imaginative vitality on this topic, there has pretty certainly been a decline on others. Any reader of old poetry can see that brightness appealed to ancient and medieval man more than bigness, and more than it does to us. Medieval thinkers believed that the stars must be somehow superior to the Earth because they looked bright and it did not. Moderns think that the Galaxy ought to be more important than the Earth because it is bigger. Both states of mind can produce good poetry. Both can supply mental pictures which rouse very respectable emotions -- emotions of awe, humility, or exhiliration. But taken as serious philosophical argument both are ridiculous.
It reminds me of Jodie Foster's comment at the end of Contact (I don't know if it's present in the novel by Carl Sagan): if we're the only living creatures in the universe, it seems like an awful waste of space. But as Victor Reppert writes, "It is not as if energy or time [or space] is a scarce resource for God and we have to ask him, if he seems to be ‘wasting’ it, why he isn't putting it to better use. ‘Waste’ is an issue only where there is scarcity."
A similar objection that I mentioned in part 1 needs further comment. I pointed out that the universe's mass density -- the amount of matter in the universe -- must be extremely fine-tuned. Otherwise, the universe's expansion would have precluded the possibility of life existing anywhere at any time in the universe's history. In other words, the universe must be the particular size it is in order for us to exist. However, one could point out that while this matter may have been necessary at the universe's inception, it seems gratuitous for it to still be here. To insist that this vast universe is all there for our sake seems absurd. Every piece of matter may have had some relevance to the universe's initial expansion billions of years ago, but there is no obvious connection between distant pieces of matter and the human race's present existence. There are plenty of galaxies billions of light years away, which have plenty of planets orbiting plenty of suns. What does a particular rock on one of these planets have to do with life on earth now? The absence of such a connection makes humanity appear irrelevant to the universe.
Ignoring my previous response, this objection assumes that life or the human race is the only possible reason why the Judeo-Christian God would have created the universe. But just because all this matter has no relevance to humanity's existence today, it does not mean that God does not delight in it for some other reason, and so sustains it in existence. Again, this point is made best by C. S. Lewis:
There is no question of religious people fancying that all exists for man and scientific people discovering that it does not. Whether the ultimate and inexplicable being -- that which simply is -- turns out to be God or "the whole show," of course it does not exist for us. On either view we are faced with something which existed before the human race appeared and will exist after the Earth has become uninhabitable; which is utterly independent of us though we are totally dependent on it; and which, through vast ranges of its being, has no relevance to our own hopes and fears. For no man was, I suppose, ever so mad as to think that man, or all creation, filled the Divine Mind; if we are a small thing to space and time, space and time are a much smaller thing to God. It is a profound mistake to imagine that Christianity ever intended to dissipate the bewilderment and even the terror, the sense of our own nothingness, which come upon us when we think about the nature of things. It comes to intensify them. Without such sensations there is no religion.
A final point: in order to assert that the premoderns thought that the earth's size somehow rendered its inhabitants significant, it would require us to believe (at least) that they thought the earth and its inhabitants significant. In order for the statement, "they believed X because of Y" to be true, it has to be true that "they believed X." The argument that they thought the earth's size bequeathed significance on humanity can't even get off the ground unless they thought humanity had significance.
But this is not the case. We've already mentioned one criterion: brightness. The earth was thought to be less important and valuable than the celestial objects because they were bright while the earth was not. Another criterion that's often misunderstood is the earth's location at the center of the universe. This is usually twisted to imply that the center was the place of prestige, but the exact opposite is the case. They thought Earth was located at the bottom of the universe, which, in their view, was the least prestigious place therein. And the further down you went, the worse it was; this is why hell was thought to be at the center of the earth, and Satan at the center of hell. Arthur Lovejoy, in The Great Chain of Being, wrote that the medieval model is better described as "diabolocentric" than "geocentric." See the essays by Dennis Danielson on this.
However, one might object that Christianity conceives human beings as being so significant that God chose to be incarnated as one to die on their behalf. But this misunderstands exactly what the Christian claim is.
Christianity does not involve the belief that all things were made for man. It does involve the belief that God loves man and for his sake became man and died. I have not yet succeeded in seeing how what we know (and have known since the days of Ptolemy) about the size of the universe affects the credibility of this doctrine one way or the other. ... If it is maintained that anything so small as the Earth must, in any event, be too unimportant to merit the love of the Creator, we reply that no Christian ever supposed we did merit it. Christ did not die for men because they were intrinsically worth dying for, but because He is intrinsically love, and therefore loves infinitely.
In other words, whatever significance or value human beings have is derivative. The moral law tells us that people do have an inherent value; the reason murder is wrong, for example, is because each individual is of infinite worth. But the reason each individual is of infinite worth is because he/she is created in God's image. And the reason God loves us is not because we are lovely or lovable, but because he is loving; indeed, the claim is that God is love itself.
(see also part 1 and part 2)
(cross-posted at Quodlibeta)