The discussions on multiverses and string theory bring to mind the following comments of David Berlinski (in “Was There a Big Bang?”):
“Standing at the gate of modern time, Isaac Newton forged the curious social pact by which rational men and women have lived ever since. The description of the physical world would be vouchsafed to a particular institution, that of modern physics; and it was to the physicists and not the priests, soothsayers, poets, politicians,…that society would look for judgments about the nature of the physical world…In exchange for their privilege, the physicists were to provide an account of the physical world at once penetrating, general, persuasive, and true.
Until recently, the great physicists have been scrupulous about honoring the terms of their contract. They have attempted with dignity to respect the distinction between what is known and what is not…
This scrupulousness has lately been compromised. The result has been the calculated or careless erasure of the line separating disciplined physical inquiry from speculative metaphysics. Contemporary cosmologists feel free to say anything that pops into their heads. Unhappy examples are everywhere: absurd schemes to model time on the basis of the complex numbers, as in Steven Hawkin’s ‘A Brief History of Time’; bizarre and ugly contraptions for cosmic inflation; universes multiplying beyond the reach of observations…theories of every stripe and variety, all of them uncorrected by any criticism beyond the trivial.”