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Our future, our universe, and other weighty topics


Sunday, November 15, 2015

What Neil deGrasse Tyson Doesn't Want You to Know About the Cosmos

In order to understand the sophistry of Neil deGrasse Tyson's recent comments on the universe, we must look at the fascinating issue of cosmic fine-tuning. Let's start at the beginning of time. Astronomers say that the universe suddenly began in the unexplained event known as the Big Bang, in which the universe suddenly began to expand from an infinitely dense point. Decades ago, cosmologists figured out that the initial expansion rate of the universe must have been fine-tuned to at least fifty decimal places, with what is known as the critical density exactly matching the actual density to fifty decimal places. You can do a Google search for “flatness problem” to find many sources stating this. There's a theory (or a family of theories) called the cosmic inflation theory designed to explain away this astonishing correspondence. But that theory requires a great deal of fine-tuning itself, in many places (as discussed here). So it's not clear that you end up with less fine-tuning if you believe in such a theory. Regardless if whether such a cosmic inflation theory is true, we can say that the universe's beginning was astonishingly fine-tuned, and that an incredibly tiny change in the Big Bang would have meant that we would not have ended up with a life-compatible universe such as we live in. (Universes that expand too fast don't form galaxies, and universes that expand too slow have their matter all collapse into black holes, or one big black hole.)

So the Big Bang was very fine-tuned, but we also find abundant and very precise fine-tuning in the fundamental constants of the universe. A dramatic example (another case of two numbers coincidentally matching to many decimal places) is found in the charges of the proton and the electron. Each proton has a mass 1836 times greater than each electron, and so you might think that each proton has an electric charge much greater than each electron. But no, we couldn't exist if that were the case. Instead each proton has a charge exactly the same as each electron, the only difference being that the sign of the electron charge is negative. The exact equality of the proton charge and the electron charge has been measured to 18 decimal places. We know that planets like the earth would not even hold together if the electron charge and the proton charge differed by even 1 part in 1,000,000,000,000,000,000,000,000,000 (as discussed by a scientist quoted here).

There are still many other cases of fine-tuning in the universe's fundamental constants. One is the astonishing case of the cosmological constant or vacuum energy density, where we see that nature seems to have miraculously balanced the books to 60 decimal places. This is again something on which our existence depends, because if things were not so precisely balanced, ordinary space would have more mass-energy than steel, as discussed here. There are also reasons why we would not be here if the gravitational constant were a little bit different, or the strong nuclear force were a little different, or the fine structure constant were a little different.

The following visual illustrates how right things have to be in order for creatures such as us to exist. Imagine someone pulling the lever on this slot machine. In order for you to get the jackpot (the appearance of life), you have to get a coincidental match on each of the rows. The chance of this happening is almost infinitely small. (This post discusses the particular items in this visual, and why each is extremely unlikely to be coincidentally compatible with life.)

cosmic fine tuning

The “lucky numbers” are only half the story, for in order to have life the universe also needs lucky laws, such as strange quantum mechanical laws assuring that electrons don't fall into the atomic nucleus, lucky laws of electromagnetism that assure that chemistry can take place, lucky laws of nuclear physics assuring that an atomic nucleus can hold together, other lucky laws of particle physics restricting the number of types of stable particles to only a handful, and a lucky Pauli exclusion principle allowing for solid matter.

So the evidence for cosmic fine-tuning is immense. This evidence has been widely discussed by scientists over the past few decades, often in discussions that used the word “anthropic.” So when Neil deGrasse Tyson was asked about this question, we expected to hear from him some substantive comments. Instead we got the following reasoning:

I look out to the universe and yes, it is filled with mysteries, but it's also filled with all manner of things that would just as soon have you dead. Like asteroid strikes, and hurricanes, and tornadoes, and tsunamis, and volcanoes, and disease, and pestilence. There are things that exist in the natural world that do not have your health or longevity as a priority. And so I cannot look at the universe and say that yes, there's a God, and this God cares about my life -- at all. The evidence does not support this.

This reasoning can be summarized like this: there exist various forms of death, so there does not exist a God who is interested in you living. This is, of course, a very bad argument. The evidence that we have is entirely consistent with the idea that there exists some higher power who wants beings such as you to exist (and who set up the universe so that you and similar beings would exist), but who does not want you to live forever in a physical existence on this planet (something which would cause various problems such as extreme overpopulation and cultural stagnation). The existence of various forms of death do nothing to argue against such a possibility. Since such a possibility is strongly suggested by abundant evidence of astonishingly precise fine-tuning in the universe, it would seem to be very well supported by evidence. The claim “the evidence does not support this” is very misleading in this case. To the contrary, there is a great mountain of evidence that Tyson has done nothing to explain away.

At the core of Tyson's statement is a most absurd non-sequitur.

There are things that exist in the natural world that do not have your health or longevity as a priority. And so I cannot look at the universe and say that yes, there's a God, and this God cares about my life -- at all.

So from the fact that there are things in the natural world that “do not have your health or longevity as a priority” we can conclude there is no God? Asteroids don't care about us, so there is no God? That's a ridiculous argument.

Tyson's argument is similar to arguments like this, and every bit as fallacious:

Somebody died in the house, therefore nobody built the house.
The house was hit by an earthquake, therefore nobody built the house.

Another related comment was this one by Tyson.

I think of, like, the human body, and I look at what’s going on between our legs. There’s like a sewage system and entertainment complex intermingling. No engineer of any intelligence would have designed it that way.

I cite this merely as an example of how absurd Tyson gets when he starts reasoning about theological topics. There is no sound basis for complaining about the design of the human penis on the basis Tyson has given, and I know of no male other than Tyson who has ever complained about the same organ being used for sex and urination. It is generally regarded as being a sign of good design when a designer gives a single object two capabilities – for example, no one complains that hammers are poorly designed because they can both hammer nails and remove nails. We also do know of intelligent designers who combine a waste disposal system and an entertainment complex. That is done by every architect who designs a movie theater, and includes bathrooms in the design. 

Having assumed the job of educating the public about the universe, Tyson should be educating the public about one of the top developments of cosmology during the past 30 years, the fact that scientists have found countless ways in which our universe is astonishing fine-tuned. But when Tyson had 13 hours of television time in his series Cosmos, he found time to discuss all kinds of unimportant digressions, but apparently neglected to even discuss the evidence that our universe is exquisitely well-calibrated for life. (I am judging from this lengthy summary, which makes no mention of such a topic.) Tyson is also director of the Hayden Planetarium, but nowhere in its vast exhibit spaces is the visitor informed about this very important conclusion of modern cosmology.

It would seem that Tyson doesn't want you to know about all the ways in which our universe is fine-tuned for life (in repeated defiance of enormous odds), because that might mess up Tyson's gloomy type of talk that emphasizes a universe “filled with all manner of things that would just as soon have you dead,a thesis we might describe as “the universe is trying to kill you.” Neil apparently doesn't want you to think about how perfectly balanced the electrical charges in your atoms are (in a coincidence we would expect to find in less than 1 in 1,000,000,000,000,000,000 random universes, the coincidence of the proton charge exactly matching the electron charge to eighteen decimal places, despite the proton mass being 1836 times greater than the electron mass). Neil would probably be much happier if you fret about some asteroid that has maybe 1 chance in a million of killing you. I may note that it doesn't make sense to cite asteroids as evidence that the universe is stacked against us. A future generation of asteroid-mining humans (with the power to deflect asteroids) may regard asteroids as one of the greatest blessings of the solar system.

Postscript:  See here for a recent post on the Scientific American web site that discusses aspects of cosmic fine-tuning.  Some of the points made are below.

The constants of nature—such as c, the speed of light, and G, which denotes the force of gravity—seem to be fine-tuned for our existence. Just a slight variation in one of these values would render galaxies, stars, planets, life and even complex atoms like those that comprise your pumpkin pie impossible...Scientists also observe a fine-tuning within the physical laws themselves—the rules, such as the laws of gravity and thermodynamics, that regulate the cosmos.