Cosmologist: Parallel universes are pushing physics too far?
|January 7, 2017||Posted by News under Cosmology, Fine tuning, Naturalism|
From Marcelo Gleiser at Nautilus:
The modern version of the unifying quest is string theory, which supposes that the fundamental entities in nature are vibrating tubes of energy instead of point-like particles of matter. Different vibrating modes correspond to the different particles we observe, just as different vibrating frequencies of a violin string correspond to different sounds. When I joined theoretical physics in the mid-1980s, the grand task was to find the unique solution to string theory: our universe with all its particles and forces. We believed success was just around the corner, that nature was indeed a mathematical code in a 10-dimensional spacetime, nine for space, one for time.
Alas, it wasn’t meant to be. Fast-forward three decades, and the scenario has changed dramatically. Physicists were shocked to find, instead of a single solution, a huge number of solutions—by some estimates, a 1 followed by 500 zeros, each a different twist in the extra-dimensional space, each generating a different universe. Presumably, each one of these has its own set of fundamental constants, numbers such as the electron’s mass and charge and the strength of the gravitational attraction, which determine nature’s physical properties. Where’s our universe among such vast number of possibilities? We do know that if we tweaked such constants by very small amounts, life wouldn’t be possible: We wouldn’t be here. In other words, we live where we live because we couldn’t live anywhere else—our universe is one of the few that allows for our existence. True enough, but as a scientific argument this buys us very little. Worse, it sounds tautological. String theory went from being the theory that would mathematically prove the uniqueness of our universe to a theory that allows a countless number of possible universes, none more compelling than the other. More.
But too far where? Thing have gone beyond the need for a multiverse to prevent fine-tuning being taken seriously as a brute fact of the only universe we know.
Aren’t we living in a post-fact world of science now? Where it is enough to just silence inconvenient information? After all, somewhere in the multiverse, the inconvenient information is not silenced, so everything averages out.
See also: Theoretical physicist: Multiverse is about how we define science: “To me, the word is now tinged with promise and fraught with possibility. It seems no more wasteful than a bower full of roses.” Not wasteful at all, if you don’t mind throwing science out.
Steven Weinberg on what’s wrong with quantum mechanics In short, it may be that his assumption that there is a multiverse, in any scientifically meaningful sense, is part of the problem. Or…?
Marcelo Gleiser: Can everything come from nothing? Even a multiverse wouldn’t solve anything, he thinks.
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