18 January 2015

Super fine-tuned worlds and infinitely many universes

The typical “our Universe is fine-tuned for life” argument states that small changes in certain constants result a lifeless Universe. For example, a 2% percent stronger strong nuclear force’s consequence would be a lifeless Universe, since the formation of heavier elements never would happen under such conditions. “Although our situation is not central, it is inevitably privileged to some extent” says Anthropic Principle’s advocate Brandon Carter [In Modern Cosmology and Philosophy (ed. by John Leslie), 1998, p. 132.].
But as Stephen Jay Gould pointed out “any complex historical outcome – intelligent life on Earth, for example – represent a summation of improbabilities and becomes thereby absurdly unlikely” [ibid, p. 187]. So our special situation is not necessarily a consequence of the fine-tuning.
Similarly, Feynman joked on his luckiness, since he had observed accidentally the ARW357 license plate although the probability of it was practically zero.
And there are other problems with arguments about fine-tuning.
First of all, life is sensitive to some physical parameters. Opposite to it, computing is insensitive to the changes of almost all of them. But it doesn’t mean that our biology is extremely fine-tuned (or extremely matches) to our Universe’s conditions. Probably either a higher or a lower speed of light would not prevent the rise of life. We can play with the idea of a universe where the result of a minor modification of any parameter would result a dead world. It is not the case in our Universe, so we do not live in a so “super fine-tuned” world.
Second of all, “to be privileged” means that the given situation is not average but applying this to the biofil universe concept, there is an unspoken presupposition behind it. If we assume that there are some other universes then uniqueness has a meaning. In other words: if we hypothesize that only a finite number of other universes exist then the “privileged position” is interpretable. But if we are suppose that infinite other worlds (no matter how we define them) exist then we have to believe that infinitely many universes of them are identical with our one. What is more, in this case the number of lifeless; the biolfil and the computable universes are equal – after all, any kind of them have infinitely many identical copies. Thus the meaning of “privileged to some extent” is uninterpretable.

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