How the Universe Began Without God

I’m blogging my way through Sense and Goodness Without God, Richard Carrier’s handy worldview-in-a-box for atheists. (See the post index for all sections.) Last time, I discussed naturalism as a worldview. Today I discuss what we know about The Nature and Origin of the Universe, based on the results of our best methods for truth-finding.

Why does the universe exist? Where did it come from? Why is it the way it is? These are tough questions, and nobody really knows the answers. Our facts are too few and uncertain. But some inferences are more plausible than others.

Let me say up front this is one of my favorite sections of the book, and I’m not usually excited by cosmology. You really should get the book to read it in its full glory.

God: the failed hypothesis

The “Goddidit” hypothesis is especially weak:

…the theory either contradicts a lot of evidence or, to avoid that, entails a huge complex of ad hoc assumptions to explain those contradictions away. Worse, the idea that there was a god around… when there was no place for it to exist, that something acted when there was no time in which it could act… is pretty much unintelligible. Some theologians thus invent a second layer of uncreated time or space for God to work in, but this is yet another ad hoc assumption for which we have no evidence and that only creates a new problem: what caused that layer of space or time to exist? …observe that the only things we have ever proven to exist are matter, energy, space, and time… Since we can explain everything by appealing to only those things and their properties, then (all else being equal) such an explanation is the most plausible one around – leaving no need… to go beyond them and invent all manner of unproven entities, like gods and spirits and miraculous powers. [Also, the god hypothesis] does not have much explanatory power. It does not follow from “there is a God” [that] “God will create this universe, just as we see it,” since any description of God that people would agree with would sooner entail a quite different universe… Second, this theory does not have much explanatory scope. Almost none of the features of the universe are explained by saying “God did it!”

Furthermore, God is a poor fit for the Big Bang. The “Goddidit” hypothesis would not predict that God should use such a long and violent process to create a messy universe, much less tiny humans in a remote corner of a vast emptiness. Why quarks or neutrinos or black holes? God needs none of these things. The god theory predicts almost nothing that we actually see.

In contrast, there are several naturalist theories that do predict the peculiar and vast universe we live in, and without resorting to all kinds of magical, ad hoc assumptions about timeless, spaceless, all-powerful, uncaused, disembodied superminds.

Let’s examine two of them.

Chaotic Inflation theory

Alan Guth‘s Eternal inflation and its implicaitons (2007) is an up-to-date summary of the evidence for Chaotic Inflation theory, and what we’d expect to discover in this century if it is indeed true.

Unlike the God theory, Chaotic Inflation makes very specific predictions about what we should find if it is true, and indeed we do find many of those things. Namely:

that the universe is unimaginably huge

the Hubble expansion

the precise uniformity of the cosmic background radiation in the observable universe, in all directions

the extraordinary “flatness” of the universe

the absence of massive, negatively-charged particles (grand unified theories predict such particles, but we do not find them, and Chaotic Inflation is the simplest way to diffuse such particles)

there were once several models that fit all the data, but recent discoveries about the angular wavelength of the cosmic background radiation have ruled out several theories, while Chaotic Inflation still stands

that there are quarks and neutrinos with the specific properties we observe

only dimensions and particles exist, which happens to be true

Despite this remarkable and precise coherence with known facts, we are nowhere near sure that Chaotic Inflation theory is correct. But after all this, it is rather laughable to think the God theory has any plausibility. The God theory predicts almost nothing in particular, and certainly nothing so specific and previously unknown as all the above!

So what is Chaotic Inflation theory? It posits that certain properties of the universe froze into place when the early universe cooled. Due to quantum indeterminacy, some parts of the universe picked up different features than others (some with no quarks, some with bigger quarks, some with smaller quarks, etc.). Then, when the universe inflated to trillions of times its original size, each of these little parts became as large as our observable universe today. So, the universe appears incredibly uniform in all directions as far as we can see, but if we could see far enough we would find other parts of the universe that behave very differently.

Cosmological natural selection theory

Another theory that fits all the available evidence – this time with one ad hoc assumption (which is still thousands fewer than the number of ad hoc assumptions required for the God theory to explain all the peculiarities of our universe) – is cosmological natural selection theory (hereafter, “Smolin Selection”).

Lee Smolin, who came up with this theory, recently wrote The status of cosmological natural selection (2006), a nice update on the theory’s status. Like Chaotic Inflation, Smolin Selection makes very specific predictions about what we should find if it is true, and indeed we do find many of those things. For example, Smolin Selection explains why:

when we smash big atoms into each other, the resulting mess of tiny particles appears in exactly the same ratio as what apparently came out of the Big Bang

our universe is fine-tuned for stars that produce carbon chemistry

the Fermi constant is in the narrow range required for supernovas to work

there is a specific limit to the mass of neutron stars

inflation must be single field, single parameter inflation

there was very little early star formation

there are quarks and neutrinos with the specific properties we observe

the universe is so suitable for black holes

All these very specific predictions follow from the mathematics of Smolin Selection, and so far they are all true. One again, the God theory looks vague, childish, ad hoc, and without any predictive scope and power compared to a genuine scientific theory like this!

So what is Smolin Selection? It all started with the observation that…

…the Big Bang looks just like a black hole. When we crash big atoms into each other in particle accelerators, they break into a whole crazy mess of particles, and it turns out that the ratio among those different particles, every time we do this, is exactly the same ratio of particles that apparently came out of the Big Bang. So the Big Bang looks exactly like what happens when you squeeze a big atom enough until it explodes… Yet this happens all the time in our universe, for that’s exactly what black holes are… Our universe is chock full of these things. There are trillions and trillions of them. Now, that’s pretty odd. It is almost as if the very purpose of the universe was to create black holes… Simply look at the facts: first, there are a lot more black holes than life-bearing planets… second, a lot more material in this universe is devoted to creating black holes than to creating life… third, this universe is almost entirely a vacuum… yet black holes thrive in a vacuum, while life is killed by it; fourth, even in this very rare, habitable pond called earth, life has a really difficult time surviving… fact number five: space is chock full of [deadly] radiation and debris, which happens to be food for black holes, but death for us; and sixth, life can be wiped out easily, and has a very hard time even getting started, yet black holes are inevitable products of the universe, and then it is almost impossible to get rid of them… Clearly, we are not made for this universe. But black holes are right at home. “God did it” does not explain this. It doesn’t even make sense of it… The bottom line? Most of this universe – by far – serves the function of producing and sustaining countless numbers of black holes.

So basically, Smolin thought: if the Big Bang looks exactly like a big mass crushed to an extreme point, and a black hole is a big mass crushed to an extreme point, then maybe inside every black hole a new Big Bang explodes into another dimension, outside our universe.

Like Chaotic Inflation, this fits with everything we know in physics. It requires only one ad hoc assumption: a new physical law requiring that when a new Big Bang explodes into a new dimension, some of the properties of the new universe will be different due to quantum indeterminacy, but some others will be “remembered” from the earlier universe that birthed it.

This is an ad hoc feature. But it has two pieces of evidence in support of it: it predicts exactly what we observe (a universe tailor-made for black holes), and does so by appealing to the only natural process that we know for a fact can produce such complexity – evolution by natural selection. For Smolin’s one single assumption produces all three ingredients: reproduction – as every universe producing black holes spawns new universes… mutation – as each universe is randomly just a little different than the next; and selection – as only those universes that are rich producers of black holes will multiply.

Summary

These are just two theories that explain the specific features of our universe with amazing accuracy, explanatory scope, and explanatory power, with either one or zero ad hoc assumptions. Contrast this with the God theory, which has no predictive accuracy, explanatory scope, or explanatory power, and dozens or hundreds of ad hoc assumptions outside known physics, and you’ll see why the God theory is such a poor explanation for our observable universe. (Also see Theism and Explanation.)

Next up, I’ll discuss section III.3.4 The Multiverse as Ultimate Being.