Saturday, April 18, 2009

Randomness, Chance, and Two Darwins

We have the usual missionary cult groups in rural Mendocino County, California, near Point Arena: Mormons, Seventh Day Adventists, and Jehovah's Witnesses. In general they seem to be pretty nice people. I don't mind them visiting their neighbors. They'll talk if you want to talk, and go away politely if you don't want to talk. It is interesting to see their opening talk lines.

A few month's ago Paul (not his real name), an earnest young man (younger than me, anyway, no big feat these days) from one of these groups, asked me, "You don't believe all of this is due to chance, do you?" His sweeping arms indicated my bishop pines, eucalyptus, the people present, the sky and the universe.

"Yes, I do," I said. That threw him. He acted as if they forgot to put that in the recruitment play book. We talked a bit more, and they left (they always seem to come in pairs, which is good, because you can offer them a beer and they'll say No).

Yesterday I read about the difference between the randomness of classical physics and the randomness of quantum physics in Inward Bound by Abraham Pais. It reminded me of how much trouble I have had accepting the nature of reality at the quantum level, of how most people are even more confused by randomness than I am, and the conversation with the earnest Christian.

I knew Paul was referring to the Theory of Evolution by Natural Selection. No, for things to be as snafu as they are in this world, you need a Central Planning Intelligence, a sort of cosmic CIA, God's designer intervention team.

Because even trained scientists have difficulty with issues of causation and randomness, you can bet (or lay odds) that religious recruiters are going to use people's confusion to lay out their own highly improbably, but very simple, causal story: God created things (and he speaks directly to the leaders of my religion, the only true religion).

Natural liberation involves understanding nature's randomness and causality. That means understanding their respective roles in the world. You need to remind yourself some times that words like chance, randomness, planning, and causality are used by humans to lump together a wide variety of natural phenomena.

It is said that some Roman soldiers worshipped Chance (Fortuna) as a god. Plato, on the other hand, did not like randomness, and preferred unseen causes to explain the otherwise inexplicable world. There are also the related ancient ideas of Fate and Free Will. Some people don't like causality because it seems to take away free will, but most people accept some causality in the "outside" world while reserving free will for people's decision making process.

A lot of this is illuminated by understanding the difference between the randomness of genetics and evolution, the randomness of classical physics, and the randomness of quantum physics.

Classical physical randomness is the best starting point. Think about dice or better still, a card game. The cards in poker are supposed to be dealt randomly, and for practical purposes we don't think about that when playing poker unless we think the dealer is cheating. But we know that each physical card maintains its physical identity from hand to hand; shuffling cards is a causal process that gives the card order a sort of practical randomness.

The classical physics problem that is solved with this sort of randomness is calculating the energy, specific heat or temperature of some matter. It is easiest with certain "ideal" gasses (ideal because the theory works out!). In classical physics everything is causal. The gas molecules all have locations, masses, and velocities. They bounce off each other in a causal manner similar to colliding marbles. But there are two many of them to use ordinary calculus to keep track of, much less calculate the temperature. By treating the molecules as having random velocities and directions, scientists could group them. The properties of the groups, fit into the right equations, give good answers. Even then this is complicated enough that scientists (notably Ludwig Boltzmann) did not get this essentially right until the late 1800's.

The point to be noticed is that in classical physics, there is no inherent randomness in matter or energy. Randomness is at the macro level, or the level of human perception. It arises out of microscopic events that are too difficult for us to keep track of. When we roll dice, they obey all of Newton's laws of physics, we just can't keep track. Nature, presumably, does keep track.

Charles Darwin's Theory of Natural Selection is covered under this classical randomness theory. Darwin did not know about chromosomes or DNA. We now know that the DNA of two parents is randomly mixed and selected for each child. This is an example of classical physical randomness: causal laws are at work on the cell level, but we can't follow them, we can only see the results. Survival until reproduction of the next generation involves both events that we classify as causal (quicker, and so escaped a predator) and random (standing in wrong place, wiped out by a flood).

I knew I was technically wrong to say, to Paul that I believe "all this" was a result of chance. There is chance involved, but evolution is really best described as causal. Its randomness is classical, a matter of humans using statistics to describe complex large scale events that are causal at a microscopic letter.

A second scientist Darwin (or fourth, if you want to include Erasmus Darwin and George Howard Darwin), Charles Galton Darwin, a grandson of Charles, was one of the many scientists who contributed to the creation of quantum physics. Coincidence, or caused by his high level of intelligence, education, and a family tradition of breaking new ground?

In quantum physics, very early on, it appeared there were truly random processes in nature. Radioactivity was the first example. Atoms of radioactive elements appear to decay randomly. So of course all the bright guys of the era set out to show that there were underlying causes for the decays. That would have set their classical physics world to right. But they could not find any underlying, classical mechanism for the randomness. In the 1920's some younger physicists started accepting this quantum randomness as just inherent in the universe. Today there is still no causal theory that explains quantum randomness. It is an simply a human observation about nature at the quantum level.

The philosophic and religious interpretations of this facet of natural reality tend to simply be used to reinforce prior prejudices. Some say quantum randomness proves there is free will. Some say it means there must be a multiverse. Many project the randomness into scales well beyond quantum physics. In fact, randomness averages out very quickly, even quantum randomness. Put a few atoms together in a molecule, and quantum randomness tones way down. By the time you have anything worth worrying about, say a few hundred molecules of gold in a lump, quantum randomness has no effect on causality. Classical physics works better.

Scientists and technicians have produce clever ways to bring quantum randomness into the world of objects that humans can see, but this is an engineering trick. Electronics parts may use quantum randomness (as in quantum tunneling), but they are themselves very predictable.

It takes a lot of study to gain even a basic understanding of quantum physics. Even the Bible is an easier read than an introduction to quantum physics text book, not to mention the mathematical prerequisites required to comprehend the equations in it. Pop quantum physics is about as useful as Bible quotes taken out of context.

Nevertheless, here's a recipe:

Two Darwins Quantum Piety

"Then said Jesus, Father, forgive them; for they know not what they do. And they parted his raiment, and cast lots [for it]." The Bible, Luke 23:34 [See also similar Matthew 27:35]

Thus is was that lots were cast at the most sacred event of the Christian religion, the Crucifixion [if it is not just a myth]. It was recorded because Fortuna wanted people to know that She does roll dice, both in the classical and quantum sense.

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