### The Harvest of Randomness

Several days ago I described four types of Darwin skeptics. "Physicists" were described as people who love the mathematical structure of the Universe and believe this math is all encompassing. Perhaps a better designation would be "determinists". They are, I suggested, resistant to three pillars of my own faith in the statistical nature of the Universe. I mentioned Kurt Gödel’s Incompleteness theorems, Heisenberg’s Uncertainty Principle and Chaos Theory.

Heisenberg’s Uncertainty Principle implies that there is a limit to the precision with which you can know about a single atom/particle. You can know where it is or how it’s moving, but not both. I believe that this uncertainty is intrinsic, not just mathematical, and the effect of a given object on its neighbor is also subject to a stochastic response. Even identical twins don’t react to each other with perfect accuracy or predictability.

Chaos Theory basically says that a relatively complex system may well be so sensitive to precise original conditions that the future of the system is not predictable through deterministic equations. Although a system might be technically deterministic, original conditions can never be measured with sufficient accuracy to emulate reality. The butterfly in Beijing flaps its wings thrice instead of twice, and two weeks later an unpredicted hurricane threatens the Caribbean. Weather, though possibly not climate, is one of those systems so complex that physics-based models predict radically different results when a single bit is changed in the data. It may be that the required quality of the input exceeds the measurability limits specified by Heisenberg, which is to say that the Universe is neither predictable nor repeatable.

What Kurt Gödel proved is that even the mathematics of a sufficiently complex system is immune to prediction or complete understanding. There will be true things within the system that cannot be proved within the system, and false things that cannot be disproved. Even if a precise mathematical model of Life the Universe and Everything were developed, it could not be counted on to explain everything.

These three ideas shook the foundations of physical science in the twentieth century. Statistical analysis became not just a way to approximate the Truth, but an essential component of the Truth. Things are stochastic. There is an irreducible element of randomness, and Life flourishes, free of determinacy, because of it.

1/22/2007 2:05 AM