Tuesday, March 21, 2017

There is a place for nonlocal physics

Any discussion of consciousness or purpose makes physicists worry that mysticism has crept into science. Physics is all about local analysis.

There is no proof that there is any action-at-a-distance, but there are many phenomena that are more easily understood with nonlocal explanations. For examples in quantum mechanics, the double slit experiment and spin entanglement experiments have nonlocal explanations.

There are many other useful nonlocal explanations, even in elementary classical mechanics. For example, a simple pendulum problem is often best explained using center-of-mass, gravitational potential, and energy conservation, and these explanations are often nonlocal.

Presumably all these experiments have purely local explanations also, even if they involve exchanging virtual gravitons at the speed of light.

For another striking example, you can put dozens of metronomes on a slightly wobbly table, and in a few minutes they will all self-synchronize. Watching this will give you the impression that the purpose of a metronome is to synchronize, and that they are nonlocally conspiring to behave in an orderly manner.

The metronome behavior can also be explained in terms of each one causing tiny vibrations in the table that alter the timing of nearby metronomes. Nobody truly thinks that there is any action-at-a-distance here. But the local theory is so much more difficult and tedious that I doubt that anyone has detailed it.

Scientists, who see the metronome demonstration for the first time, usually think that it is some sort of magic trick. It looks as if inanimate objects are communicating with each other to coordinate their activities. This violates their sense of what is scientifically possible, like a magician pulling a rabbit out of a hat. They do not want to believe that objects can have a purpose.

The concept of (Lagrangian or Hamiltonian) action also gives nonlocal explanations. The evolution of a system is a stationary point of the action integral. Minimizing the action relies on a nonlocal analysis.

Thermodynamics also makes use of nonlocal explanations. It is based on local theories of heat energy, but then predicts that the entropy of the system increases. Sometimes a system will seem to have a mind of its own as components conspire to reach thermal equilibrium.

You might say that the purpose of inanimate objects is to conserve energy. At the simplest level, motion can often be explained as objects doing what they can to conserve energy. Likewise, you can say that the purpose of life is to exploit past low entropy. The entropy of a system is always increasing, and living beings, if present, are always searching out low entropy and making use of it. Life can be seen as an attempt to postpone thermal equilibrium by finding sources of low entropy and extracting useful energy. When an organism dies, its purpose also dies, and it decays towards equilibrium conditions.

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