July 21, 2006

Shostak: Is SETI Barking Up the Wrong Tree?

Seth Shostak is once again trying to justify the work of SETI. But seeing as that's his job, it's to be expected. He has to perpetually defend the work of SETI to secure public support and funding.

Shostak notes that there are four primary suggestions as to why SETI hasn’t found a signal:
1. “You’re counting on the aliens using communication technology (radio, light) that’s oh-so-last century. They will be far beyond this.”

2. “If hi-tech societies or thinking machines were out there, they’d have colonized the Galaxy by now. Clearly, we’re alone… lone… lone.”

3. “The aliens don’t want to communicate with us. Look at what we’re doing to the planet!”

4. “You SETI types are just looking in the wrong places. We know where the extraterrestrials are: on a planet in the Zeta Reticuli system.”
Reasons #1, #3 and & #4 are useless, but #2 is one I'm partial to. As I've written before, the apparent dearth of ETI's in our galaxy is a disturbing observation.

In response to suggestion #2, Shostak writes:
This is, of course, an appeal to the Fermi Paradox, which assumes that if sophisticated societies are common, they should also be ubiquitous. Well, I just checked the parking lot outside the Institute, and I see no large animals with long, prehensile noses. The conclusion a la Fermi is that elephants don’t exist on this Earth, right? After all, any putative pachyderms have had plenty of time to get to my office, even if only a few of them are so inclined. To use the Fermi Paradox as a reason for the lack of a SETI signal is to make a very big extrapolation from a very local observation. Seems chancy to me.
This is a surprisingly weak answer from Shostak who has clearly misinterpreted the FP. No one is arguing that elephants should be ubiquitous. If we thought, for whatever reason, that elephants should occupy specific ecospaces on Earth, but they don't, then that would be a sort of observational conundrum much like the FP. I don't expect this, so I don't see this as a problem.

On the other hand, our expectations of AETI migratory behaviour and their potential megascale engineering projects are a horse of a different colour. The FP is about the absence of evidence when there should be evidence. And Shostak knows this; otherwise he wouldn't be pointing his radio arrays at the sky. It would be a convenience of the highest order if the first signs of ETI life were to be discovered now.

Shostak and others are guilty of grossly underestimating the characteristics of post-Singularity AETI's. Those, like Shostak, who dismiss the FP betray a misunderstanding of the potentials of artificial superintelligence, radically advanced computing and such technological artifacts as Von Neumann and Bracewell probes. And as usual, these dismissals fail to take into account the extreme age of the universe and the huge expanse of time that has preceded our own.

That said, Shostak may be (inadvertently) right about ETI localization. As argued by Cirkovic and Bradbury, AETI's may migrate from a biological habitable zone to a technological habitable zone -- one more conducive to megascale information processing projects like matrioshka and Jupiter Brains.

But Shostak and SETI, I'm sure, aren't considering these types of scenarios. My advice to SETI: keep on listening, but don't expect to hear anything.

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5 comments:

Michael Anissimov said...

My advice to SETI: please stop wasting our money. There are no aliens. Sorry. If you want to see an alien, make one.

The absence of aliens shows us what an amazingly low probability there is of a self-replicating molecule forming to begin with.

Chris said...

Ok, I'm not a scientist, but is SETI even good science? I mean, you could keep scanning for centuries, millenia, and if you found nothing you could still insist that absence of evidence is not evidence of absence. How is that research into a testable hypothesis?

Don't get me wrong, I'm certain that the universe is crawling with life - although I expect that technological civilizations are probably rare. I'm just not certain that "We'll just keep looking until we find what we expect to find" is necessarily good empirical science.

George said...

Michael: SETI is important and they should keep on listening because a negative data result will re-affirm alternate theories about ETI existence and behaviour. My problem with SETI is that they expect to hear something; of course, they could never acknowledge this, otherwise they'd lose all their funding. Read this:
http://www.aob.bg.ac.yu/~mcirkovic/AB_4_2_p225-231.pdf

Your second comment is a sort of referrence to the Rare Earth hypothesis. You'll have to quantify what you mean by "amazing low probability" in the context of trillions of stars and a galaxy that has been able to foster life for the past 8-9GYR. In other words, given the vast number of stars and extreme age of the Galaxy, even a "low probability" will yield life and intelligence on a potentially large scale.

George said...

Chris: I happen to think that the SETI assumption is reasonably sound. Sure, there's a bit of philosophy and extrapolation involved, but I look at it as a project to look for data where we have a strong suspicion that the data exists. Imagine all the science that wouldn't be done if we didn't look for things that we didn't know were there. Take microscopes and telescopes for example and the novel discoveries that were made as a consequence of looking in places we never thought to look before.

Again, like I wrote to Michael -- negative data results in science are fine, in fact they're great -- they are often as important as positive results. The apparent failure of SETI has forced us to deal with the Fermi Paradox and re-evaluate our conceptions of what AETI is and does.

Ryan said...

I have to agree the SETI project seems increasingly like a waste of money and effort.

Wouldn't all those resources be better used to advance our own civilization? Espeically in areas like singularity producing AI which are extremely under or even non-funded.

Even if we find a signal, so what? Its not like we are in a position to have meaningful conversation or dealings with civs that are lightyears away, if it is even possible.