02 December 2005

SETI isn't ID

Sclerotic_rings pointed me towards a nice article contrasting SETI with ID. SETI, the Search for ExtraTerrestrial Intelligence, is a project that is systematically, scientifically (not pseudo-scientifically) searching for a signal from space that could only be created by other intelligent life. They're not interviewing people who had anal probes and inside-out cows; they're scanning the sky for radio signals.

The adherents of Intelligent Design ... point to SETI and say, "upon receiving a complex radio signal from space, SETI researchers will claim it as proof that intelligent life resides in the neighborhood of a distant star. Thus, isn’t their search completely analogous to our own line of reasoning—a clear case of complexity implying intelligence and deliberate design?" And SETI, they would note, enjoys widespread scientific acceptance.

If we as SETI researchers admit this is so, it sounds as if we’re guilty of promoting a logical double standard. If the ID folks aren’t allowed to claim intelligent design when pointing to DNA, how can we hope to claim intelligent design on the basis of a complex radio signal? It’s true that SETI is well regarded by the scientific community, but is that simply because we don’t suggest that the voice behind the microphone could be God?


The article goes on to discuss that SETI is actually searching for artificial-ness, not complex-ness, and in this case simplicity of the signal (one frequency) is what will indicate the signal is artificial. But there is another issue that the article misses, as pointed out to me a while ago by Jason, if we were actually searching for a complex signal. And that is that normal noise we get from space is not self-reinforcing in any manner, but natural selection is.

A message from space, a piece of information such as that, can be essentially pared down to digits, just like a sentence has letters and spaces, or a number has a numeral in each place. If an astronomer finds a pattern such as "1234", the astronomer has to analyze what's the random chance of finding those specific four numerals in that order out of any other outcome of four digits. There is no physical process going on that would influence how one piece of data is going to come out after the previous piece of data. (In math/statistics terms, the outcomes of each digit are independent events.) Therefore there's 10,000 different possibilities (0000-9999), so the chance of getting that particular pattern is 1 in 10,000. As the "message" becomes increasingly complex, and remains a "message" and not a mess, the chances are even lower that it happened randomly. Since the noise (random numbers) are not reinforcing, complexity has no natural reason to form, so any complex signal has a low chance of forming randomly or naturally.

Evolution, on the other hand, is not random (but it is natural). We are not arguing that creatures were created randomly like drawing numbers out of a hat as we were in the previous example. Instead, every step along the way reinforced what was going on. A slime that sits there is less likely to survive than a slime that can move. Creatures that can sense light are more likely to detect prey. It's not like we have two different versions of a creature and roll dice to determine which survives, natural selection picks the one better suited to its environment, the one with additional features that make it likelier to survive and reproduce. Events in evolution are dependent. Natural selection is not a random process, it is a chain reaction that in this case has an end result of complexity.

To clarify my point, here are some other examples.

Requires A Creator

  • Sand does not turn into glass and then into telescopes spontaneously.

  • Coal does not turn into power stations, then electricity, then a sine wave radio broadcast all on its own. This is what SETI is looking for.

Does Not Require A Creator:

  • A lump of uranium-235 decays into thorium-231 and causes a chain reaction of further decays. This chain reaction is uncontrolled and in fact is very hard to stop, as places like Chernobyl, Three Mile Island, Hiroshima and Nagasaki, and Oklo all demonstrate. You don't need any big hand coming down from the sky to push each little nucleus to fall apart, the multiple neutrons released from previous reactions does that for you!

  • A massive cloud of hydrogen gas is self-gravitating, becomes a big lump in the middle, which starts fusion in the center, that changes hydrogen into helium, near the end of its life you actually get a complexly layered system where each layer going inward has progressively more massive elements. (See Wikipedia's stellar evolution article for more information.) It happens on it's own! If it didn't, we wouldn't be here today, as that sorta thing's where all the oxygen in the universe was formed.

Once again, insufficient understanding of the scientific (and mathematical) concepts involved (statistics and random independent events vs. nonrandom dependent events) has done them in. If they're going to try and argue that ID is science, they need to do a better job of understanding what science is all about.

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