The Nature and Origin of the Universe

1. Big Bang

Scientists have amassed a wealth of evidence confirming that the universe we can see began about fourteen billion years ago as an incredibly hot, dense kernel of energy, which inflated under pressure, expanding and cooling to produce the known world. This event is called the Big Bang, from which scientists can explain almost everything that has happened since: how the immutable particles and forces of nature led all by themselves to a vast expanse of billions of complex galaxies and sheets of galaxy clusters stretching farther than the eye can see; how within each galaxy there arose billions of stars, which altogether sport billions of planets; and how, on at least one of those, life could arise by a natural accident, evolving into us. This is the story as scientists have so far been able to suss it. The facts support it fairly widely and well.

The important questions that remain are why this Big Bang happened at all, and why it produced this particular universe, rather than some other. And this is where “God did it” is now often proposed. But it is an awkward fit. What does God need a Big Bang for? That’s a terribly slow, messy, complicated way to create a universe, much less people. Why the long, complex process of condensation from energy to matter to stars to galaxies? Why the vast expanse of the end result? You would think a god would simply create the whole universe at once, or much more quickly at least, and only make it as large as would suit us. There would be no need of long drawn-out processes, nor of other planets or galaxies, much less all the hundreds of subatomic particles we know of.

“God did it” doesn’t predict any of these things, nor does it explain them very well. God has no need of quarks, for example, or neutrinos, or galaxies, or billions of years of slow, mechanical processes. Nor can we make any predictions about any of these things from the “God did it” hypothesis. Can we deduce from “God did it” how many types of quark there are? Or that there should even be quarks? Or how long it would take that god, from the initial moment of creation, to make a human being? Or that there would be such things as galaxies? Or such thongs as neutrinos?

Sure, you might invent a vast and clever array of detailed assumptions about a god or his plans that could predict or explain all this, or you can resort to something vacuous like “God’s ways are a mystery,” but either way you would only be making the god hypothesis less plausible than any naturalist theory that already predicts and explains all these strange things. And there are several theories that do that. Scientists are testing them even as we speak. The god hypothesis, by contrast, makes few if any testable predictions.


2. Multiverse

Chaotic Inflation theory is a reasonable inference from contemporary scientific observations and understanding, and predicts everything we observe. It holds that those properties of the universe that can be different than they are, like the mass of quarks, “froze” into place when the universe cooled, and due to chaotic or quantum indeterminism, different parts of the universe randomly ended up with different features—some with no quarks, some with quarks of a different mass, and so on. Yet the universe inflated so quickly, that once these properties froze in place in each tiny spot, that area grew to a size thousands of times larger than we could ever see. Thus, the universe we observe appears everywhere the same—but if we could see far enough, we would see different parts of the universe with completely different properties. It follows from the same theory that many regions of this multi-faceted universe will collapse and start the whole process over again, causing more multi-faceted universes to emerge from the original one. And so on. There is nothing we know that could stop this process, so it must go on forever—and may already have. So if inflation did occur, and it was chaotic, then nearly every possible universe would exist, including ours.

The above theory is not mere speculation. Every element builds entirely on known science. Inflation itself, chaotic or random behavior at small scales, “freezing” at larger scales, collapsing regions jump-starting inflation again, inflated regions being much larger than any distance we could see, etc. All these things actually follow from known scientific facts and established theories, based on empirical observations. Most scientists are in agreement about this. And that makes for a pretty strong argument, although we have yet to find direct evidence for this kind of mechanism at the origin of our universe, and that is what scientists are now looking for.

More info: https://en.wikipedia.org/wiki/Eternal_inflation

3. The Ultimate Being

In the realm of cosmology, the debate between theism and atheism is really only a quibble over details. Both sides agree there must be some ultimate entity, which is the eternal first cause and ground of all being, the end point of all explanations. They only disagree over what properties this “ultimate being” has. Theists think it has a whole plethora of amazing powers and attributes, including the most complex mind imaginable. But as atheists point out, there is no evidence for any of those tacked-on assumptions. There are only two properties we can be sure the ultimate being has: its nature is to exist, and it had a reasonable chance of producing our universe exactly as we see it. We can’t say anything more than that without sufficient evidence. And there is no actual evidence for any of the traditional divine attributes.

We’ve already examined how the belief that there is an infinite array of different ‘universes’ is more plausible than a god, and we’ve seen there is at least as much evidence for that as there is for a god, if not substantially more. For this reason (as well as others), metaphysical naturalists conclude that the “ultimate being” is probably this ensemble of universes. We have no evidence the ultimate being consists of anything more than that, and this being is sufficient to explain everything else we observe, better than any alternative so far.

Such an ensemble of universes is formally called a “multiverse.” That can be misleading, since in neither of the most plausible theories is there really any more than one ‘universe’ per se. In Chaotic Inflation, different ‘universes’ are really just different regions of the same universe, even when in some cases these other regions are hidden within black holes. Nevertheless, it has become the convention to employ “universe” to refer to a single distinct region of what is in turn called the “multiverse.”

The multiverse explains everything that exists, and so even from the start it is just as good as “God did it.” It is even better than that, since the multiverse fits and follows from known scientific facts, and it makes the exact features of this universe highly probable—whereas there is no reason to believe this is the universe a god would probably make, nor is there any evidence that a god actually did any of the making. Of course one could ask why the multiverse exists at all, and why it has the exact properties it does. But something must exist without any explanation at all, so it may as well be the multiverse. For if a god can exist unexplained, with all his convenient attributes, then so can the multiverse. Both solutions leave the same questions unanswered. But we find the god hypothesis leaves far too many more questions unanswered. So we take the multiverse instead, as our ultimate “brute fact.”

In fact, the multiverse is a simpler explanation than god, because it has all those attributes of god sufficient to ground its own being and cause this universe to exist, minus all that stuff about intelligence, knowledge, desires, or omnipotent powers. So it does the same work with less baggage. For example, the multiverse is eternal, in the sense that it exists at every point of time that exists, has existed, or ever will exist. And for that reason it did not come “from” anywhere. There was never a time when it did not exist, so it did not come from “nothing,” because there has never been “nothing.” There has always been “something,” from which every universe is born. And yet, having no knowledge or intentions or supernatural powers, the multiverse is a much simpler entity than a god—requiring fewer unproven assumptions.

It is sometimes said that a multiverse is not at all simple because it proposes a large number of entities to explain only one. But the multiverse is a single entity, not many. The existence of countless ‘universes’ or ‘regions’ within the multiverse is actually entailed by a very small and simple set of assumptions, a far simpler set than that required to make sense of a god. Of course, all of those assumptions are more or less supported by at least some evidence, whereas none of the peculiar assumptions about a god are. But even besides that, once you accept the basic elements of Chaotic Inflation, the existence of countless universes follows necessarily. It does not have to be assumed. So these theories really involve only one or two leaps of speculation, since the rest is grounded in established scientific facts. In contrast, god’s attributes comprise a rather lengthy laundry list of speculations, unsupported by any science. And that is why, as explanations go, a multiverse is simpler than a god.

Therefore, I believe it is most probable that a mindless multiverse exists, has always existed, and exists by nature. I don’t claim this as anything more than a good hypothesis. But I believe it is more probably true than any other explanation so far, because it is the simplest and most plausible answer, explaining the most things by appealing to the fewest unknowns. And it fits. The theory that our universe had a mindless physical cause perfectly predicts the universe we observe: a dispassionate, mechanical, mindless, physical cosmos. It makes complete sense of why we are made of frail matter, why life developed through a long and messy process of evolution, why the universe is so big and old, why we can never find any good evidence of supernatural beings or events, and so on. Since this is a plausible, comprehensible explanation for the universe, until we discover some evidence that challenges it, there is no need to resort to any alternative. And until some facts are discovered that better support some other hypothesis, there is no reason to look for any other.