Fine-tuning in a Multiverse
Most recent answer: 07/07/2015
- Jonathan (age 16)
Tucson, AZ, USA
There are a couple of adjustments to make in what you've understood from other discussions.
The usual multiverse story makes no claim that universes have to be just like this one in order to exist. The claim is that any universe with basic laws a bit different from this wouldn't persist long enough with enough interesting chemistry going on to allow the formation of intelligent life. So the claim is not that different types of universes aren't "there", it's that nobody is in them asking why the laws are just the way they are.
Secondly, although some of the parameters (notably the cosmological constant) require amazingly precise tuning to allow for life, so far as we know none require absolutely exact tuning. So the philosophical problem of asking whether identical copies are really copies or just the same thing doesn't have to come up.
Please follow-up if those adjustments don't suffice to take care of your questions.
(published on 07/07/2015)