‘Sizeism’ is a coined term to describe the prejudice which seems in-built in a modern conception of the universe and its nature. As we continue to explore space through increasingly sensitive technologically capable devices, we commonly come across the viewpoint C. S. Lewis describes in his book Miracles about the immensity of the cosmos:
Many people say, 'They could believe in miracles in olden times because they had a false conception of the universe. They thought the Earth was the largest thing in it and Man the most important creature. It therefore seemed reasonable to suppose that the Creator was specially interested in Man and might even interrupt the course of Nature for his benefit. But now that we know the real immensity of the universe—now that we perceive our own planet and even the whole Solar system to be only a speck—it becomes ludicrous to believe in them any longer. We have discovered our insignificance and can no longer suppose that God is so drastically concerned in our petty affairs' (chapter 7, A Chapter of Red Herrings).
However, this view rests upon the myth that the immensity of the universe is a recent discovery. The truth is that Ptolemy, who was alive in the second century AD, taught that in relation to the distance of the fixed stars, the whole Earth must be regarded as a point with no magnitude. Ptolemy’s astronomical system became the basis of that of the Dark and Middle Ages. The modern idea of an ignorant Middle Ages is the falsehood; the spatial insignificance of Earth had been asserted by Christian philosophers, Christian poets, and Christian moralists for one and a half millennia.
Lewis goes on:
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. Many a man, brought up in the glib profession of some shallow form of Christianity, who comes through reading Astronomy to realise for the first time how majestically indifferent most reality is to man, and who perhaps abandons his religion on that account, may at that moment be having his first genuinely religious experience.
From the modern misconception come various other idly held beliefs.
One is that, if the Earth is so small, it must therefore be insignificant and unworthy of the attention of a universal God. This brings in the question of size: something tiny must, goes this argument, be something correspondingly meaningless or unworthy. Lewis addresses the idea that merit has anything to do with the size of things in two ways:
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. And what after all, does the size of a world or a creature tell us about its 'importance' or value?
This second way - the notion that something’s size determines its value - is illuminating because it is easy to illustrate the folly of it:
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.
Examples abound: is an empty room more significant than a child because the room is larger? Is an eye less significant than a football because one is smaller that the other? The supposed logic falls away immediately:
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, then 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 superiority in size begins to produce in us only after a certain point.
The emotional difference is one which has developed over time, as Lewis explains:
This suggests a possible answer to the question ... 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?... 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 that rouse ... emotions of awe, humility, or exhilaration. But taken as serious philosophical argument, both are ridiculous. The atheist's argument from size is, in fact, an instance of just that picture-thinking.... What we fondly call 'primitive' errors do not pass away. They merely change their form.
So in considering Lewis’s view on the nature of the cosmos, as his use of the older view of space and the planets as a poetic tool, one of our customary ways of potentially ridiculing or dismissing the whole thing cannot be admitted: size is an irrelevancy.