Quote from jcl:
A scientific theory can not be proven. It can only be falsified. Proof only exists in mathematics.
A scientific theory is considered valid, or "highly plausible" if you want, when it is consistent with all observations, and when it gives a better or simpler explanation than competing theories.
This is so far the case for string theory and multiple universes.
This does not mean that string theory is "proven", as anytime a new and better theory can come up. However string theory gives natural explanations for the big bang and for the fine tuning of our local universum.
penrose stated string theory is just a collection of ideas.
Scientific theories produce testible, falsifiable results. The idea of multiverse is pure conjecture.
String theory itself is probably not even a scientific theory.
The math suggests there could be 10 to the 500 solutions or ways a universe could form.
Its pure conjecture to say those solutions are actually real.
http://www.nytimes.com/2006/01/15/b...w/15powell.html
Although string theory resists translation into ordinary language, its central conceit boils down to this: All the different particles and forces in the universe are composed of wriggling strands of energy whose properties depend solely on the mode of their vibration. Understand the properties of those strands, the thinking once went, and you will understand why the universe is the way it is. Recent work, most notably by Joseph Polchinski of the University of California, Santa Barbara, has dashed that hope. The latest version of string theory (now rechristened M-theory for reasons that even the founder of M-theory cannot explain) does not yield a single model of physics. Rather, it yields a gargantuan number of models: about 10(to the) 500, give or take a few trillion.
Not one to despair over lemons, Susskind finds lemonade in that insane-sounding result. He proposes that those 10500 possibilities represent not a flaw in string theory but a profound insight into the nature of reality. Each potential model, he suggests, corresponds to an actual place - another universe as real as our own. In the spirit of kooky science and good science fiction, he coins new names to go with these new possibilities. He calls the enormous range of environments governed by all the possible laws of physics the "Landscape." The near-infinite collection of pocket universes described by those various laws becomes the "megaverse."
Susskind eagerly embraces the megaverse interpretation because it offers a way to blow right through the intelligent design challenge...