Welcome to the Goldilocks Planet
Why the "Big Universe" Argument Fails
The following is from my upcoming book.
Materialists often argue that the universe is big; therefore, God does not exist. If you looked at that sentence and your first thought was that the conclusion clearly does not follow from the premise, you are right. Whoever said God cannot create a big universe? Moreover, for proponents of the multiverse, this objection is not only logically incoherent but also a contradiction. Multiverse theory predicts that grand universes are typical. So, to assert this objection, a multiverse proponent would have to say that God can’t create a big universe, but the multiverse generator, if it exists, has done it many times, maybe even an infinite number of times. It makes no sense.
In fairness, I take it that the materialists’ “big universe” objection is not a strictly logical one. Instead, it is an argument from incredulity, i.e., claiming that a proposition is false simply because someone has difficulty believing it. For instance, imagine you are transported back to 1803, a century before the Wright brothers’ first powered flight, and you find yourself in an auditorium debating someone about the future of technology. With the advantage of being a time traveler, you assert that one day, metal machines hundreds of feet long will carry dozens of passengers tens of thousands of feet in the air and transport them across oceans. Suppose your debate opponent responds, “You’re crazy. Metal can’t even float; that’s why we build ships out of wood. Now you’re saying that a metal machine will someday fly through the air like a bird. Insane.” Your opponent would be arguing from incredulity. They would, of course, be wrong, but they would nevertheless almost certainly be declared the winner of the debate because no one in the audience would believe you either. I never claimed that arguments from personal incredulity aren’t effective. They certainly are. They just aren’t logical, and they can lead us astray.
Those who assert the big universe argument are relying on a dynamic similar to your debate opponent. The argument goes like this. The ancients had no conception of the scale of the universe and the earth’s place in it. It was easy for them to imagine that the universe is kind of small and that the earth is at the center of it. But Copernicus came along and demolished the idea that the earth is special, and in the 1920s, we discovered that there are millions of other galaxies out there,[i] and that knowledge demolished the cozy little universe idea. The cold hard facts are that earth is an insignificant speck in an insignificant galaxy in a vast universe. There is no reason to believe that a God exits who cares about humans wandering around on that tiny speck.
Carl Sagan presented a classic example of the big universe argument while reflecting on an image of earth taken by Voyager I[ii] from billions of miles away:
Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives…Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.[iii]
Sagan’s argument boils down to the assertion that he cannot imagine why God would care about creatures who live on a tiny speck in a vast universe. But a critical unanswered question is: “Why should the poverty of Carl Sagan’s imagination concerning God’s motivations matter to us?” Nevertheless, like your debate opponent, while Sagan’s argument is not logical, it is undeniably powerful, and many people refuse to believe that God exists because of arguments like it.
There are many problems with the argument, not the least of which is that Sagan is glaringly wrong when he says there is “no hint” that God exists. There are far more than hints that God exists. There is overwhelming evidence that he exists.
Let’s consider the first premise of the big universe argument – the ancients believed we live in a cozy little universe. The problem with the premise is that it is pure bunkum, as anyone with the faintest grasp of the history of cosmology knows. Ptolemy’s Almagest was, by far, the most influential book on cosmology ever written if one measures influence by time. Ptolemy published the Almagest around 150 AD, and his geocentric model remained the standard model of cosmology for nearly 1,400 years until Copernicus De Revolutionibus Orbium Coelestium was first printed in 1543.[iv] That was 482 years ago. Copernicus has over 900 years to go before his span of influence matches Ptolemy’s.
While Ptolemy’s geocentric model was ultimately displaced, that doesn’t mean he was wrong about everything. For example, he knew the Earth is a sphere.[v] Another thing he knew is that the scale of the universe is mind-bogglingly vast. He wrote: “Moreover, the earth has, to the senses, the ratio of a point to the distance of the sphere of the so-called fixed stars.”[vi] Thus, according to Ptolemy, the earth has no “perceptible size in relation to the distance of the heavenly bodies.”[vii]
Ptolemy was not the only ancient who knew the universe is vast. The Psalmist was fully aware of his insignificance in relation to the cosmos. Writing circa 1,000 BC, he said:
When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained;
What is man, that thou art mindful of him? and the son of man, that thou visitest him?
For thou hast made him a little lower than the angels, and hast crowned him with glory and honour.[viii]
It is hard to believe that Sagan was unaware that the ancients knew about the vastness of the universe. After all, in The Demon-Haunted World, he cited Ptolemy’s demonstration that the earth is a sphere,[ix] which occurs only a couple of pages before the text I quoted. C. S. Lewis might have been on to something when he related the following conversation with one of his friends:
Friend: The whole picture of the universe which science has given us makes it such rot to believe that the Power at the back of it all could be interested in us tiny little creatures crawling about on an unimportant planet! It was all so obviously invented by people who believed in a flat earth with the stars only a mile or two away.
Lewis: When did people believe that?
Friend: Why, all those old Christian chaps you’re always telling about did. I mean Boethius and Augustine and Thomas Aquinas and Dante.
Lewis: Sorry, but this is one of the few subjects I do know something about. You see this book, [handing over the Almagest] You know what it is?
Friend: Yes, it’s the standard astronomical handbook used all through the Middle Ages.
Lewis: Well, just read that.
Friend: “The earth, in relation to the distance of the fixed stars, has no appreciable size and must be treated as a mathematical point!” Did they really know that then? But – but none of the histories of science – none of the modern encyclopedias – ever mention the fact.
Lewis: Exactly. I’ll leave you to think out the reason. It almost looks as if someone was anxious to hush it up, doesn’t it? I wonder why.
Lewis: At any rate, we can now state the problem accurately. People usually think the problem is how to reconcile what we now know about the size of the universe with our traditional ideas of religion. That turns out not to be the problem at all. The real problem is this. The enormous size of the universe and the insignificance of the earth were known for centuries, and no one ever dreamed that they had any bearing on the religious question. Then, less than a hundred years ago, they are suddenly trotted out as an argument against Christianity. And the people who trot them out carefully hush up the fact that they were known long ago. Don’t you think that all you atheists are strangely unsuspicious people?[x]
The first premise of the “big universe” argument cannot hold up under scrutiny. What about the second premise, the idea that Copernicus demonstrated that the earth is not the center of the universe (sometimes called the “Copernican principle” or the “mediocrity principle”)? It turns out that this idea has not held up well either.
First, the ancients did not think of the earth as occupying an honored place at the “center” of the universe. Rather, it is more accurate to say that the earth’s “sublunar” position is the nasty bottom of the universe.[xi] More importantly, in their groundbreaking book, The Privileged Planet, Guillermo Gonzalez and Jay Richards convincingly demonstrate the earth is special after all. Gonzalez and Richards discuss all of the parameters that must be simultaneously balanced for a planet to exist that supports life that is capable of observing the universe. The parameters for such a planet include:[xii]
· It orbits an early G dwarf star that is at least a few billion years old
· It orbits a star in the in the galactic habitable zone
· It orbits a star near the corotation circle and with a low eccentricity galactic orbit
· It orbits a star outside spiral arms
· It orbits a star with at least one terrestrial planet in the circumstellar habitable zone
· It is one of the terrestrial planets in the circumstellar habitable zone
· It orbits a star with no more than a few giant planets comparable in mass to Jupiter in large, circular orbits
· It has a low eccentricity orbit and is outside the region where giant planets would destabilize its orbit
· It is near enough to the inner edge of the circumstellar habitable zone to allow high oxygen and low carbon dioxide concentrations in atmosphere
· It is in the right mass range
· It has a proper concentration of sulfur in its core
· It has a large moon and the right planetary rotation period to avoid chaotic variations in its obliquity
· It has the right amount of water in crust
· It has steady plate tectonic cycling
· It is a planet where life appeared
· It had a critically low number of large impacts
· It was exposed to a critically low number of transient radiation events
· It is a planet where complex life appeared
· It is a planet where technological life appeared
· It is a planet where technological civilization has not destroyed itself
Gonzales and Richards assign a (almost certainly too high) chance of ten percent for each of the factors. Multiplying the combined probability of only the first 13 factors by the number of stars in the Milky Way, Gonzales and Richards calculate that the total expected number of habitable planets in the Milky Way is 0.01. In other words, it turns out that it is highly unlikely that even one planet in the Milky Way is habitable, much less hosts a technological civilization that can observe the universe. The Earth beat the odds and is a privileged planet after all, and that giant crashing noise you hear is the second premise of the “big universe” premise falling down like the first.
What about the possibility of other life forms in the universe? Even if the probability of life is much lower than we thought, what if it is discovered? C. S. Lewis also contemplated this issue. This is is his response:
Christianity says what God has done for Man; it doesn’t say (because it doesn’t know) what He has or has not done in other parts of the universe. [You] might recall the parable of the one lost sheep. If Earth has been specially sought by God (which we don’t know) that may not imply that it is the most important thing in the universe, but only that it has strayed. Finally, challenge the whole tendency to identify size and importance. Is an elephant more important than a man, or a man’s leg than his brain?[xiii]
Lewis’s final point is particularly significant. An implicit assumption of the “big universe” argument is that in a vast universe, the physical insignificance of Earth implies its metaphysical insignificance as well. But why should that be? Size and importance have no logical connection.[xiv] A diamond is many times smaller than a ten-ton boulder, yet it is also many times more valuable. It seems to me that until materialists can demonstrate (rather than merely assert) that the size of the earth is necessarily linked to its value to God, they should be more modest in making their claims.
[i] It is easy to lose sight of the fact that Edwin Hubble proved the existence of galaxies other than the Milky Way only a little over 100 years ago in 1923.
[ii] The pale blue dot image is reproduced at Gonzalez and Richards, The Privileged Planet, 238.
[iii] Sagan, Pale Blue Dot, 12-13.
[iv] For the sake of simplicity, I assume that Copernicus immediately displaced Ptolemy. That is not the case.
[v] Ptolemy, Almagest, Book I, Chapter 4 (page 40 of text of translation).
[vi] Ptolemy, Almagest, Book I, Chapter 6 (page 43 of text of translation).
[vii] Ibid.
[viii] Psalm 8:3-5.
[ix] Sagan, The Demon-Haunted World, 305.
[x] Lewis, “Religion and Science,” in God in the Dock, 74-75.
[xi] Gonzalez and Richards, The Privileged Planet, 226. The immutable celestial regions beyond the orbit of the moon were considered far superior to the sublunar region. Id.
[xii] These bullets are drawn from Appendix A to The Privileged Planet.
[xiii] Lewis, “Christian Apologetics,” in God in the Dock, 100.
[xiv] Guillermo Gonzalez, “Do We Live on a Privileged Planet?” in Dembski, Luskin, and Holden, ed., The Comprehensive Guide to Science and Faith, 239.