Scientific American Challenges the Multiverse
A few months ago, Scientific American ran a piece by University of Cape Town cosmologist George F.R. Ellis titled "Does the Multiverse Really Exist?" The upshot of the article was that if it does, then science has no way of discovering it. In essence, it is an unscientific concept that has its roots in philosophy. As a summary within the article stated:
The trouble is that no possible astronomical observations can ever see those other universes. The arguments are indirect at best. And even if the multiverse exists, it leaves the deep mysteries of nature unexplained.Many of the Star Trek series and spinoffs (i.e., the original series, Deep Space Nine, or Enterprise) have it as a recurring theme that crew members are accidentally transported into an alternate universe. In one such dystopian alternate universe, the Nazis won World War II, and humanity took a sinister and violent direction. The "Federation" is not a benevolent coalition of planets, but an empire that seeks to dominate other worlds. If such alternate universes exist, is there any possibility we could interact with them like they do in Star Trek? According to Ellis, no:
(George F.R. Ellis, "Does the Multiverse Really Exist?," Scientific American (August, 2011).)
All the parallel universes lie outside our horizon and remain beyond our capacity to see, now or ever, no matter how technology evolves. In fact, they are too far away to have had any influence on our universe whatsoever. That is why none of the claims made by multiverse enthusiasts can be directly substantiated.So if there's no possible way to observe or interact with the many alternate universes predicted by the multiverse, why are do some scientists advocate this idea? According to Ellis, they're trying to get around the evidence for the fine-tuning of our universe:
Fundamental constants are finely tuned for life. A remarkable fact about our universe is that physical constants have just the right values needed to allow for complex structures, including living things. Steven Weinberg, Martin Rees, Leonard Susskind and others contend that an exotic multiverse provides a tidy explanation for this apparent coincidence: if all possible values occur in a large enough collection of universes, then viable ones for life will surely be found somewhere. This reasoning has been applied, in particular, to explaining the density of the dark energy that is speeding up the expansion of the universe today. I agree that the multiverse is a possible valid explanation for the value of this density; arguably, it is the only scientifically based option we have right now. But we have no hope of testing it observationally.Buying more lottery tickets will give you better odds of winning the lottery. In the same way, multiverse proponents hope that inventing more universes will help them explain the insanely small probability of finding a universe whose physical laws are finely tuned for life. So the motive for believing in a multiverse stems from a materialistic philosophy that hopes to overcome the evidence for design. Unfortunately for multiverse proponents, as Ellis points out, "we have no hope of testing it observationally."
Just how finely tuned is our universe? According to Roger Penrose, the initial entropy of the universe must have been fine-tuned to within one part in 10 raised to the 10123 power. That's not 1 in 10 with 123 zeros after it. That's 1 in 10 with 10123 zeros after it. And that's just for one physical parameter. The fine-tuning of our universe is a big problem for materialists.
Ellis -- who doesn't seem to be a proponent of intelligent design -- closes by explaining the difficulty that physicists have had in explaining cosmic fine-tuning without invoking teleology:
Proponents of the multiverse make one final argument: that there are no good alternatives. As distasteful as scientists might find the proliferation of parallel worlds, if it is the best explanation, we would be driven to accept it; conversely, if we are to give up the multiverse, we need a viable alternative. This exploration of alternatives depends on what kind of explanation we are prepared to accept. Physicists' hope has always been that the laws of nature are inevitable -- that things are the way they are because there is no other way they might have been -- but we have been unable to show this is true. Other options exist, too. The universe might be pure happenstance -- it just turned out that way. Or things might in some sense be meant to be the way they are -- purpose or intent somehow underlies existence. Science cannot determine which is the case, because these are metaphysical issues.Ellis argues that detecting purpose lies outside of the realm of science, but if we base our views upon scientific observations, we are nonetheless left with the following:
- The laws of nature exhibit an incredibly unlikely degree of fine-tuning that is required to produce a life-friendly universe.
- There is currently no physical explanation for this fine-tuning.
- We can observe our universe, and no others.
- This unlikely fine-tuning represents astronomically high levels of specified complexity embedded in the laws of nature.