Sunday, May 6, 2018

Natural Selection as the Hand of God

God is the Perfect Creator, that is, Infinite Selectivity.

Boethius thought about it this way:

"If something is to be found imperfect in its kind, there must necessarily be something of that same kind which is perfect. For without a standard of perfection we cannot judge anything to be imperfect. Nature did not have its origins in the defective and incomplete but in the integral and absolute; it fell from such beginnings to its present meanness and weakness." (Consolation of Philosophy, Book III, Prose X)

But is it true that there must be a perfect example of everything? For instance, is there really a perfect table out there somewhere? It doesn't seem that there could be. By what actual process could you arrange a collection of atoms into perfect flatness, sturdiness, and beauty? There will always be some flaw, it would seem. So how can Boethius say that a perfect table MUST exist out there?

We can conceive a perfect table, even if we can't make it. So, at the very least, it must be admitted that the concept of a perfect table exists.

And this is, of course, all that Boethius, who was a Platonist, meant. In fact, this is precisely his point. All table makers are imperfect, so it necessarily follows that all tables are imperfect.

"For all perfect things have been shown to come before less perfect ones. And so, if we are to avoid progression ad infinitum, we must agree that the most high God is full of the highest and most perfect good."

A perfect carpenter could, if desired, make a less than perfect table. But for a very poor carpenter to make a perfect table would be extremely unlikely. If it happened that a novice carpenter made a table perfectly flat, smooth down to the molecular level, you would call it astronomically lucky. 

But what about the human organism? The intricacy of the human body is so great, that it is next to impossible for it to be built by any set of unguided chance events working on what started as chaotic dirt, water, and air.

Genesis 2:7: "And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul."

According to Genesis, dirt came first. A world "without form" (1:2), and then light and darkness (1:3-4), and then dry land (1:9), and then photosynthetic organisms (1:11), and then God made "the waters bring forth abundantly the moving creature" (1:20), and then he made humans (1:26).

Genesis also says that plants were created before the sun, but I don't see how this is possible except in a metaphorical sense, i.e., that the sun is something more excellent in quality to ancient eyes than the grass. Creation proceeded from the simpler to the more complex, and humans were the final step in this process. It is amazing that a document that was written by pure inspiration thousands of years before we had realized what fossils were could have been so accurate. There must be something deeply true in this account, that has formed of the foundations of the most fruitful religions for so many centuries.

***

The world is billions of years old. This can be seen by looking at geological processes. Dust is deposited no faster than by meters over the course of centuries. When you look at the layers of rock in the cliff faces of the Rocky Mountains, you see thousands of meters of layered deposits that have been compressed over time into rock. This takes at least hundreds of thousands of years. By looking at layers around the world and tabulating their results, and cross-referencing with what they've found by measuring the radioactive decay of uranium to lead and potassium to argon in certain rocks, they've determined that the earth is probably around 4.5 billion years old.

As a physics undergraduate at Caltech I measured the speed of light. What I got was pretty close to the official number, which is about 30,000 kilometers a second. In one year light can travel almost a trillion kilometers. So we call this distance a light year. But there are galaxies in the night sky that are millions of light years away. That means that the universe must have been around for at least millions of years.

Whales have tiny hip bones. They serve no purpose whatsoever. Humans have tiny tail bones, which don't do much either. Some snakes have vestigial leg bones.

Interestingly, cows and horses have very similar diets but very different ways of digesting their food. Cows and other ruminants have four stomachs. Horses, however, have an enlarged appendix used to ferment the plant matter they eat, as do gorillas. We humans do some fermentation, but it all happens in our intestine. Our appendix doesn't do enough that we can't live without it. Gall bladders in humans also often cause trouble, and once removed the body doesn't seem to miss them much.

The oldest fossils are the smallest and simplest. Land animal fossils don't appear until less than 440 million years ago. Dinosaur fossils start out small and get bigger towards more recent layers. You see the same pattern with mammals, which didn't start getting bigger until the dinosaurs disappeared.

Over the eons life has diversified and grown in complexity. It has had several setbacks, major extinction events, including some that drove over 90% of multicellular organisms extinct. But following these events, you see new flurries of creation and somehow diversity quickly bounces back to even higher levels than before. Why it has kept doing this is a great mystery. I would guess that those species-lineages that are most creative have survived to become gradually more creative and better at bouncing back. Obviously those lineages that are fragile to cataclysm will have dwindled in the face of their flourishing competitors. And here we see natural selection at work. You have a diverse variety of species and only the most fecund survive.

Natural selection is unavoidable. Those that reproduce fastest, that survive most surely, will predominate in numbers. Those that dwindle will eventually disappear.

Mutation, too, that mother of diversity, is also unavoidable. When DNA is copied, there are sometimes errors. It is because of mutation that every human being on this planet has a unique set of DNA.

Where there is mutation and selection, it is unavoidable that adaptation happens. And it is conceivable that species can change radically, especially over very long periods of time.

There are many problems with the notion that the universe is only a few thousand years old. Starlight from stars more than 6000 light years away (which is most of the stars in the sky) would have been created in transit to the earth, which would be absurd. Even St. Augustine argued that the account in Genesis must be mostly metaphorical. Why shouldn't we allow that each "day" of creation could have been millions of years, especially as the sun itself wasn't created until the fourth "day"?

But if only the more perfect can create the less perfect, why does Genesis say that God started by creating the simple and ended with the complex? This would seem to be backwards, if creation is supposed to progress from more perfection to less. You might think he started with the angels, and then angels created mankind, and mankind then created the apes and animals, and so on.

Another thing Genesis says is that God created Man in His own image. If this is true, then our carpenter analogy may be of some help.

When God created Man, he started with dust. When a carpenter makes a table, he starts with wood. A carpenter does not start by making a more perfect table and then letting it create the less perfect table. Rather, he starts by shaping each part of the table, and then putting them together. Similarly, God started with all the pieces of human life: light and darkness, the sky, water, land, plants, animals.

And how does the carpenter shape each part? He starts with a formless piece of wood ("the earth was without form") and then shapes it, making it smoother and more perfect as he progresses. Similarly, God's process of creation starts with random mutations and shapeless diversity and chisels it down by natural selection to something more perfect.


***

Could it be that matter is all there is? And if this is true, how could God have a hand in creating animal and plant species? If natural selection and mutation suffice to create all life, however complex, then wasn't it blind processes, not God, that gave rise to humanity?

Here is an interesting puzzle. What about the ancient doctrine that the more perfect must create the less perfect? If this is true, then how could we have been created by some blind process of natural selection and mutation?

As I contemplate this, I can't help but feel that natural selection is a kind of game. You have winners and losers, you have cooperation and deals and strategy as intricate as you want, and you have very strict rules. In fact it's all in the strictness of the rules. Without powerful and consistent natural selection, mutation would just lead from more perfection to less, and this is what actually happens in nature when a species is extremely successful. It's happening today with humans, as the selective forces on our DNA weakens and our bodies descend over the generations to less perfection, as does our culture. It is when the game is hardest, as in dark or primitive ages, that evolution toward perfection starts again. (This is a very Chestertonian picture I have in my head, by the way, if you've read Everlasting Man; it is also a very Taoist picture, I think.)

But it also seems to me that the world constitutes a very special sort of game. In college I made friends with a professor who liked to play around with self-replicating computer programs--"artificial life" as it's known. The challenge is not to get these programs to replicate. The code for that is very easy. The challenge isn't even to get them to mutate. Nor is it hard to make them prone to natural selection. In fact, if you don't put much thought into the rules of the game, the code that replicates fastest, and that therefore wins by natural selection, tends to be the shortest and simplest code. It runs through its own instructions as fast as possible to get to the good stuff, self-replication. You end up with very stupid programs, if you don't actually force them to do anything interesting. If you let them they will quickly become viruses, making use of each other's code to pay less CPU time and use up less disk space. (I believe it was in the program called "Tierra" that they first really studied this behavior.)

Finally, my professor said look, give these programs something interesting to do. Make them earn their replication privileges. So he started giving them logical problems. He changed the rules of the game so that if they could calculate these logical operators (he chose IF, NOT, AND, OR, NAND, XOR, etc.) they would get big rewards. Also, he started rewarding them just for being longer programs. And all of a sudden the programs started evolving toward greater length and sophistication.

Evolutionary algorithms are used in a lot of applications, and more today than ever. But the blind processes of mutation and natural selection are not, in themselves, sufficient for interesting complexity. It takes a heck of lot of design to create the right games for evolving useful algorithms.

The world we live in, the world whose game it is we humans were selected to play, is a very special sort of game. This game that evolution has been playing, the rules of this game, cause the patterns in our DNA and our culture. A game without rules creates nothing. Depending on the rules, you might create something simple or complex, stupid or interesting, beautiful or ugly. Not all games are interesting. Not all games are worth playing. In fact, if you've ever trying to design a game, you will learn how very hard it is to come up with rules that produce anything fun at all.

It is in the rules of the game itself, I believe, that you will find the greater perfection that created us. This seems very clear to me, but it is difficult to explain.

Some of the rules of our world are inexorable and eternal, and have been here since the beginning, and will always be here. The laws of physics. Conservation of energy. The rules of chemistry. But also the Golden Rule. Divine Perfection. Human imperfection.

Other rules of our game are indeed changeable. The laws of a nation. Conservation of money. The rules of economics. But also the winds of fashion. The rules of a specific ecosystem. The degree of perfection of an organism.

At the very least you must grant that the world we humans live in is extremely exceptional, perhaps even infinitely selective. And it is Infinite Selectivity that is the Perfect Creator, that is God.

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