Sunday, December 7, 2008

Quick, someone call a philosopher

I think this Andrew Sullivan reader has it wrong:

A reader writes:

I think that Mr. Ward doesn't understand certain things about the scientific process. He writes:

If a belief is forced (you cannot avoid it), vital (of great practical import), and living (a realistic and plausible option), then, James suggests, it is rational to commit yourself to it even with less than overwhelming evidence. That seems to me to do no more than reflect the practice of good scientists when they believe that “there is no event without a cause,” “there are universal laws of nature,” or “the universe is comprehensible and mathematically intelligible.

These are hypothesis, not just beliefs. There is a difference, and it has to do with whether or not your beliefs can change as the evidence changes. These hypothesis can and have changed as more evidence has accumulated.


Take, for example, the weather. There are no real fundamental scientific issues concerning the weather, and there haven't been for quite some time. There are, for example, no scientists hoping to overthrow General Relativity or the Standard Model by looking at thunderstorms or hurricanes. Likewise, as far as I know, there are no religious bodies that claim that we cannot predict next week's weather because of Weather Gods that make it rain, or that Hurricanes and tornados (both highly organized structures) show evidence of Intelligent Design.

However, we now know that the weather is, in a deep sense, not "comprehensible and mathematically intelligible." The weather is chaotic, and is not predictable more than a few weeks into the future. We will never be able to predict whether it will rain in some location August 1, 2020, at least not until July, 2020, rolls around. This was a surprise to the mathematicians and meteorologist working in weather prediction; they expected to be able to predict the weather like astronomers predict the motions of the planets. John von Neumann even thought we could control the weather by using its chaotic nature. He was wrong and they were wrong and people have adjusted their thinking.

Unlike in (most) religion, there are no scientific hypothesis (beliefs) that could not be changed if the evidence so indicated.

Claims like “there is no event without a cause,” “there are universal laws of nature,” and “the universe is comprehensible and mathematically intelligible" are not hypotheses within science--they are assumptions that science itself rests upon. Indeed, as David Hume pointed out some time ago--and as any freshman Philosophy undergraduate is taught--it is impossible to derive the necessity of cause and effect from empirical data. And, along the same lines, you cannot somehow empirically demonstrate that the universe behaves in a law-like way that is comprehensible to humans.

The example involving weather is quite a bad one. He takes the unpredictability of weather to be evidence that, in at least one respect, the universe is "not comprehensible or mathematically intelligible." But nonlinear systems like the weather are mathematically intelligible--in fact, there is a whole branch of mathematics that deals with irreducibly complex systems like that, and scientists have had much success replicating these systems using computer simulations. So there is nothing incomprehensible or mathematically unintelligible going on there.

In short, this Sullivan reader doesn't know what he's talking about and his response never should have gotten posted to the blog. Indeed, if Sullivan himself were on duty, I'm sure he would have vetoed it, since if I'm not mistaken he has a Philosophy degree from somewhere fancy. But Sullivan is on vacation and his assistent Patrick Appel is running things, so we get this.

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