Wednesday, April 25, 2007

the new planet

By now you've heard that a European team of scientists, based primarily in Chile, has discovered a planet remarkably like our own, and is excited about (1) the possibility that this world has or can support life, and (2) the possibility that many, many other such Earth-like worlds are scattered throughout the universe. The planet is only 20 or so light years away; it's a next-door neighbor, cosmically speaking.

I somehow doubt the newly discovered planet, which is the most Earth-like world we know of,* is populated with humanoids. It would be interesting to discover whether this planet did, in fact, harbor life of some sort... and if that life turned out to be sentient, I wonder what damage that would do to the vaunted anthropic principle, which claims that only a very narrow set of conditions is conducive to the existence of human or human-like beings. If beings of comparable intelligence and ability have evolved elsewhere, under substantially different conditions, I think it would be wise to toss that principle out as the arrogant tautology it is.

(For more on the tautological nature of the anthropic principle, see here, the "Criticisms" section. Scroll down a ways. In fairness, I should note that whether the principle is a tautology, in either its "strong" or its "weak" forms, is a matter of debate.)

*The planet, Gliese 581c, sports a small, "cold" star, has about twice the earth's gravity, probably has some sort of atmosphere, and has a "year" that lasts only 13 Earth days as it whips around its primary.



Malcolm Pollack said...

Hi Kevin,

I don't think that finding life in the Gliese system would be particularly relevant to the validity of the anthropic principle, except in its strongest, narrowest, human-centric and teleological sense.

Presumably the same delicate and seemingly unlikely balance of natural laws and constants would be necessary for the formation of life there as well (the Gliese-monkeys would still need stars, heavy elements, time to evolve, etc., all of which depend on the conditions that apply in the universe we happen to find ourselves in). Even if the "anthro" in "anthropic principle" originally refers, of course, to humans, the principle itself is, of course, more general than that.

I think the "strong" versions of the AP are rubbish. The weaker version, though, may have interesting implications for cosmology and fundamental physics; certainly it poses an interesting question.

Unknown said...

I should note that whether the principle is a tautology, in either its "strong" or its "weak" forms, is a matter of debate.

No, it isn't.

There is no weak interpretation without a multiverse, unless you can prove that the mechanism that constrains the universe produces carbon based life as an un-necessary consequence of the physics, rather than the reason for it that is indicated by the pointed nature of the physics.

Strong interpretations have the potential to define the ToE, whereas, *proven* weak interpretations can falsify the strong implication.

Until that happens, the universe is observed to be strongly anthropically constrained.

Kevin Kim said...


I'm simply reporting the fact that there is a debate. The existence of the debate is undeniable. Perhaps there shouldn't be a debate (because one side or the other feels the matter is closed), but that's not what I was reporting.

My own opinion is that the anthropic principle in all its forms is baloney, but given my lack of PhD-level science expertise, I'm very much open to a thorough explanation as to why that might not be so. I don't abide dogmatism.


gordsellar said...


I'm with you that the anthropic principle is baloney in all its forms.

Of course, finding complex life (not necessarily intelligent in a way recognizable to us, but sufficiently complex to make us recognize it as complex) would in fact be taken by adherents of the anthropic principle as proof that their theory is correct.

After all, the "anthropic" principle, at least as put forth by Tipler and his homeys, is that the universe is predisposed to a certain kind of ramping-up complexity, which runs parallel to the laws of thermodynamics. Energy in systems bleeds out, but those systems tend towards complexification, such that this may well be a cosmic adaptation, if indeed our universe is one of a complex set of evolutionarily linked universes in a multiverse. The bottom line being that "anthro" in that framework means "complex enough to be intelligent and sentient like us", but not necessarily "like us". Any encounters of intelligent life would be taken as proof that a tendency toward complexity is built into our universe. (And the weak form may have some traction, perhaps, but more from arguments Freeman Dyson has made about the weight of... was it helium? or hydrogen? I can't quite recall.) The weak form being just that there'
s a tendency toward complexity. Wolfram and his acolytes seem to suggest this too, though I'm not far enough into A New Kind of Science to know what I think about old Stephen yet, except that he's dreadfully repetitive and makes his point a million times, a bit distrustful of the reader. (Reminiscent of Schumann's horrid orchestrations when he finally went mad... every instrument doubled by something all the time, just in case a cue was missed.)

If if if... have you read Frank J. Tipler's The Physics of Immortality? It's hilarious but also a little scary; he starts arguing Sufi scripture as proof of his personal (and very idiosyncratic) theory of the Omega Point as a kind of end-of-time deity that will resurrect us all in a future-virtuality.

When that was published, many many people finally wrote Tipler off as having lost it. I was among them, and remain so. But if you read it as a kind of Nabokovian novel with an insane narrator (vaguely like Pale Fire) it does hold some interest. As a text purporting to unify religion and science, it would perhaps be of some interest to you.

Unknown said...

Hi Kevin,

Cosmological principles are supposed to define the physics that determines the structure and dynamics of the universe from first principles.

As a cosmological principle, the anthropic constraint on the forces most apparently indicates that we are *specially* relevant to this mechanism, so the expectation is that we are intricately woven into the least action of the universe in a manner that defies all attempts to date to model the evolution of the universe from first principles.

Answering that question is what is called for here, before you can say that it is crap, otherwise, your worldview does not fit the observation and you stand ideologically biased against the implication without justification.

Weak interpretations don't include any of this, as they only define a selection effect, rather than a cosmological principle, and you have to prove that this interpretation supercedes the explanation from first principles before you can say that a weak interpretation is more plausibly in effect.

The fact that string theorists and Richard Dawkins jump on the weak bandwagon doesn't mean a damned thing unless that they can prove that the multiverse is even necessary to the explanation with a valid proven theory of everything, or possibly, a complete theory of quantum gravity.

Until that happens we're stuck with the strong appearance and no explanation for it, other than John Wheeler and Paul Davies' attempt to explain the structure via observer dependent quantum mechanics.