Einstein actually said something prescient in the context of the current debate.
What I am really interested in knowing is whether God could have created the world in a different way.
The answer from string theory appears to be that ‘God’ could! So we have to bring in the anthropic principle to rationalize being in this world rather than another.
String theory provides an embarras de richesses and the possibility of a vast array of different worlds.
Not all string theorists are on board with the anthropic multiverse. David Gross describes it as not testable in principle, some speculative suggestions notwithstanding. (As a string theorist, he does think string theory is testable in principle.) Sean Carroll, on the other hand, who is supportive of the multiverse idea, posits the removal of the falsifiability criterion in the identification of a legitimate scientific theory – explanatory power might be sufficient in itself.
This would be a major departure from the way science is conventionally conceived.
Maybe that’s just how it is and we have to get used to such limitations.
But I think even if I were a string theorist I would at least want to find some way of paring down the complexity and sheer flexibility of it all. Selection criteria provided by a novel insight - independent of the anthropic principle - to whittle down the myriad vacua and attendant worlds of string theory would be welcome.
The ideas of Copernicus and Kepler allowed the increasingly convoluted theory of epicycles to be simplified and ultimately replaced, providing a good example of the process mentioned by contortionist.
Perhaps we are due another fundamental shift in our way of thinking.
And talking of epicycles, I'd rather like to sign off with another Einstein quote I'm fond of - despite being an atheist:
The fanatical atheists are like slaves who are still feeling the weight of their chains which they have thrown off after hard struggle. They are creatures who—in their grudge against traditional religion as the "opium of the masses"—cannot hear the music of the spheres.