Monday, May 28, 2012

Why the Multiverse is not Currently a Valid Response to the Fine Tuning Argument

The most common objection to the fine-tuning argument (see for a brief summary of the fine-tuning argument) is that there exist a very large number (possibly infinite) number of universes.

Unfortunately, the multiverse is currently an untested hypothesis. If you don't believe me, just ask page 24 of physicist Victor Stenger's The Fallacy of Fine-Tuning, which probably contains the strongest arguments to date against the fine-tuning argument. You could also ask other physicists like Brian Greene: Also, if you have the urge to read a post on string theory, let me know and I can do a post on string theory.

That is not to say that we will never be able to test for the existence of the multiverse. In fact, we will probably be able to test for the multiverse within our lifetimes thanks to the Large Hadron Collider in Geneva, Switzerland. Until we can test for the multiverse, we should not assume that it exists. To do so would be to make an assumption which currently does not have enough evidence to validate it.

In addition, the mere existence of the multiverse is not enough by itself to refute the fine-tuning argument. Two additional facts must be established.
  1. Physical constants must vary from universe to universe
  2. There must be a large enough number of universes to counter-act the unlikeliness of fine-tuning
It is important to note that string theory does have the implication that physical constants will vary from one universe to the next, and that there will be a large number of universes.

Anyway, while it is easy to assume that the coolest, most cutting edge, sexiest hypotheses in physics will turn out to be true, it is not a good idea to assume what the conclusion will be before the evidence has been gathered. Once we get a reasonable amount of evidence, we can include the multiverse in our discussion. Until then, we must argue fine-tuning without it while including the caveat that if the multiverse turns out to exist, it is very likely that the fine-tuning argument will be drastically weakened.

No comments:

Post a Comment