January 13, 2009

Our non-arbitrary universe: A SentDev Classic

As scientists delve deeper and deeper into the unsolved mysteries of the universe, they are discovering that a number of cosmological parameters are excruciatingly specific. So specific, in fact, that any minor alteration to key parameters would throw the entire universe off kilter and result in a system completely unfriendly to life.

Consequently, some have considered this as evidence for a designer, giving rise to teleological arguments like intelligent design. Others claim that the universe is spontaneously finely tuned.*

There are several theories that try to explain why the universe is so finely tuned: 1) anthropic observation in consideration of an ensemble of universes [Carter, Leslie], 2) the "participatory anthropic principle" which implies that observers force the universe into existence [Wheeler], and 3) that natural selection has endowed the universe with its particular characteristics [Smolin, Smart].

On the last point, that of natural selection, the obvious question is, if the universe is a replicating entity, and if its attributes are the result of natural selection, why must the universe also be so biophilic? In other words, couldn't the physics of the universe develop such that it was merely a replicating entity that didn't necessarily have to support life?

One possible answer is that there are many types of spontaneously replicating universes, some of which support life, and some of which do not. If this is the case, we happen to observe one such universe that supports life, and our existence is irrelevant to our universe's life cycle.

However, if we find that the universe we live in is the only feasible type of universe possible, and that it is a replicative system prone to selectional processes, then we might have to conclude that intelligent life plays a crucial role in the universe's life cycle. In other words, advanced intelligences help the universe to replicate.

As Freeman Dyson once wrote, "The more I examine the universe and study the details of its architecture, the more evidence I find that the universe in some sense must have known that we were coming. There are some striking examples in the laws of nuclear physics of numerical accidents that seem to conspire to make the universe habitable."

I first encountered this argument via John Smart's developmental singularity hypothesis, where he suggests that advanced intelligences may spawn new baby universes soon after the technological singularity event. More recently, I discovered an article on KurzweilAI by James N. Gardner in which he argues for the selfish biocosm hypothesis.

Gardner's argument is quite interesting. He writes that two recent discoveries have imparted a renewed sense of urgency to investigations of the anthropic qualities of our cosmos, specifically 1) the value of dark energy density is exceedingly small but not quite zero, and 2) the number of different solutions permitted by M-theory is astronomical -- measured not in millions or billions but in googles or googleplexes. Again, what he's suggesting is that the universe is finely tuned to the point of absurdity.

According to Gardner's theory, "the laws and constants of physics function as the cosmic equivalent of DNA, guiding a cosmologically extended evolutionary process and providing a blueprint for the replication of new life-friendly progeny universes."

As Gardner notes, theories of cosmological eschatology have previously been articulated by Kurzweil, Wheeler and Dyson, all of whom have essentially predicted that, in Gardner's words, "the ongoing process of biological and technological evolution is sufficiently robust and unbounded that, in the far distant future, a cosmologically extended biosphere could conceivably exert a global influence on the physical state of the cosmos." Some cosmologists, like Milan Cirkovic, have argued that the universe's life cycle should not be studied without referrence to the influence of intelligent life.

Specifically, it is thought that intelligences, in conjunction with advancing technologies, will act as "von Neumann controllers" within a cosmologically extended biosphere and function as a "von Neumann duplicator" in a hypothesized process of cosmological replication.

I find this topic to be exceptionally interesting, and I hope that more consideration is given to it in the coming years, particularly the issue of cosmological eschatology and the role that intelligences may have in the life cycle of the universe.

*Browsing through Wikipedia, I found some examples of 'fine tuning':
  • The nuclear strong force holds together the particles in the nucleus of an atom. If the strong nuclear force were slightly weaker, by as little as 2%, multi-proton nuclei would not hold together and hydrogen would be the only element in the universe. If the strong force were slightly stronger, by as little as 1%, hydrogen would be rare in the universe and elements heavier than iron (elements resulting from fusion during the explosion of supernovae) would also be rare.
  • The nuclear weak force affects the behavior of leptons (e.g. neutrinos, electrons, and muons) that do not participate in strong nuclear reactions. If the weak force were slightly larger, neutrons would decay more readily, and therefore would be less available, and little or no helium would be produced from the big bang. Without the necessary helium, heavy elements sufficient for the constructing of life as we know it would not be made by the nuclear furnaces inside stars. If the weak force were slightly smaller, the big bang would burn most or all of the hydrogen into helium, with a subsequent over-abundance of heavy elements made by stars, and life as we know it would not be possible.
  • The electromagnetic coupling constant binds electrons to protons in atoms. The characteristics of the orbits of electrons about atoms determines to what degree atoms will bond together to form molecules. If the electromagnetic coupling constant were different atoms and molecules would be different; maybe not even exist.
  • The ratio of electron to proton mass also determines the characteristics of the orbits of electrons about nuclei. A proton is 1836 times more massive than an electron. If the electron to proton mass ratio were different, atoms and molecules would be different — or maybe not even exist.
  • The entropy level of the universe affects the condensation of massive systems. The universe contains about one billion photons for every baryon. This makes the universe extremely entropic, i.e. a very efficient radiator and a very poor engine. If the entropy level for the universe were slightly larger, no galactic systems would form (and therefore no stars). If the entropy level were slightly smaller, the galactic systems that formed would effectively trap radiation and prevent any fragmentation of the systems into stars. In either case, the universe would be devoid of stars and solar systems.
  • The force of gravity affects the interaction of particles. In order for life as we know it to form, the force of gravity must be 1040 (10 to the 40th power) times weaker than the force of electromagnetism. The relationship of gravity to electromagnetism as it currently exists is this: The positively charged particles must equal in charge the numbers negatively charged particles or else electromagnetism will dominate gravity, and stars, galaxies and planets will not form. The numbers of electrons must equal the numbers of protons to better than one part of 1037 (10 to the 37th power).

This article was originally published on March 2, 2006.


ArcAnge1M said...

Don't get too caught up in the results. I like to say that math is made of the universe, not the other way around. We made the mistake of thinking our little system of numbers (descriptions) built this whole thing. Arrogant of us, no?

Anonymous said...

I share a similar sentiment - the Fine Tuning hypothesis is terribly anthropocentric.

ano said...

My problem with fine tuning is that it doesn't appear to explain anything. It selects some nice examples and with a wink and a nudge informs you that suddenly it's reasonable to consider the otherwise currently unprovable.

Ultimately I'm perfectly satisified with the explanation that everything's 'just so' because we wouldn't be here if it were anything else. The only universe in which intelligent life can arise (unless seeded) is a sufficiently stable one. I'm not too clued up on extra-universal physics but is it not possible that the laws of physics are slightly different in other brane interfaces? thus in another universe a proton can have slightly different mass and that universe can still work?

Dunno. And it doesn't give us answers even if you do decide the universe was the result of intelligence's actions.

Decent work for philosophers I suppose =p

melior said...

So life "as we know it" would not be possible, or would be different. But would (intelligent?) life "as we don't know it" and probably can't even imagine it have its own version of the anthropic principle?