Is there a Universe?
Seems obvious enough. We’re in it; it must exist. Yet there there are several ways of doubting that there is a universe.
One is the Gnostic path which says we cannot be sure of anything. The philosopher, (the Gnostic philosopher) wonders whether he just dreams he is seeing a butterfly; then he goes on to wonder whether the butterfly is actually dreaming him! It is not possible to deal with this. If you can’t just say, “Yes, there is a butterfly,” then we’re done. Come back when you get over it.
Come back, that is, when you decide that since you will certainly conduct your life and your butterfly net and your conversation with your curious child in a manner that assumes there is a butterfly, you may as well forego schizophrenia and its philosophic shadow, solipsism, and be realistic. Gratefully take as a given the reality of those things which are clearly unified in consciousness until you have a specific reason to doubt a specific perception.
It is one?
Is it unified?
The second way of doubting that there is a universe is to doubt that the universe is truly one, to doubt that it is a unified whole. Sometimes this doubt comes in the form of saying that the universe is one of several universes; sometimes it comes in the disguise of saying that the universe is infinite.
As for being one of several universes, the answer is fairly simple:
- If there are many universes, either they interact, or they do not.
- If they interact, they are really only one universe, possibly spread out in a lumpy way, but still they are one.
- If they don’t interact, there is no scientific way to know of one from within the other. We cannot weigh, count, or otherwise measure things that do not interact with the matter of our own universe.
Of course something can exist even if we don’t know about it. But from the perspective of the natural sciences – those fields of knowledge characterized by measure – we cannot know about them and there is nothing scientific to say. Scientists are always pontificating about other universes, and as human beings, such opinions are certainly their prerogative: but what they have to say is not scientific. It’s philosophy; or it’s math; or it’s some combination of imagination, philosophy, and math. It’s not science, and if scientists want to do it, they ought to clarify that they are just chattering outside their field of expertise.
An Infinite Universe?
But the infinite universe is not so obviously wrong. Indeed, for at least the middle third of the 20th century, the prevailing cosmology – the prevailing opinion about the universe – was that it was infinite. The Steady State theory of the universe was that hydrogen atoms were constantly being created in the empty spaces of the universe, that enough of them would produce suns and galaxies, and that the galaxies were prevented from becoming too dense by their spontaneous movement away from each other.
To finish off this fairy tale, it was thought (if you can call it a thought) that as the galaxies retreated from each other faster and faster, the most distant would eventually reach the speed of light in their recession, and would then effectively cease to be part of the universe we live in. For when their light could not reach us, neither would their gravity, and they would thereby cease to be part of the universe – for us. Oddly, however, they would be part of the universe of other things closer to the edge of our universe. This contradictory state of affairs does not appear to have had a rigorous philosophical examination, and it was the prevailing cosmology for a long time, at least until 1965.
I am not sure where it began. Certainly the idea of an infinite universe was floated from time to time, at least as far back as late 15th century Giordano Bruno. It may not go back much farther since it was thought, certainly until some time after Copernicus, that the “world” – the earth with its moon, its sun, and five wandering planets — was fairly contained within the circle of the fixed stars. That was the single universe.
But why is it contradictory for parts of “my” universe to be parts of other universes that are not “mine?”
Think of it this way:
Suppose that my universe is very small, consisting of me, my little planet that I live on, and two neighboring asteroids that circle round me according to the laws of gravity.
Now suppose that there exists some other planet, which is close enough so that my asteroids are part of its universe when they are on one side of me, and not part of it when they are on the other side.
Do you see the problem? Sometimes my asteroids will be pulled away from me, maybe even captured, and thus their gravitational response to me will be stronger or weaker depending on how close they are to this other planet. So you see that this other planet becomes an important part of how my world works. Surely then, it is part of my universe.
In. Or out. An infinite universe tries to have it both ways.
Material things are Countable
There is an even simpler point about the difficulty with an infinite universe. Simpler to make, but perhaps harder to grasp. It is this: material objects can be counted. That is one of the properties of material existence. If there are a lot of things, it might take a long time to count them, but you could plop numbers on them out of the sky, as it were, and after the numbers landed, you could pick the largest and say that the number of material objects was no greater than this number.
But you couldn’t plop the numbers onto an infinite set of stars; there would always be more, immense realms more, of unnumbered stars. Such a state of affairs is opposed to material existence. An infinite spiritual universe is possible. An infinite imaginary universe is imaginable. An infinite material universe is not possible. Getting confused about the difference between what is possible and what is merely imaginable is a philosophical mistake.
A common one, but quit it. That’s the best plan.
Read Full Post »