In a SciFi novel, Isaac Asimov said that two is an impossible number.A set of parameters/conditions might be so restrictive that they cannot be satisfied: Hence zero is a possible number. A set of parameters/conditions might descibe some unique phenomenon, entity, object, whatever: Hence one is a possible number. If there are two phenomena, entities, objects, whatever which satisfy a set of parameters/conditions, there will some other phenomonom, entity, object which also satifies that set of parameters/conditions: Hence two is an impossible number.The above was in the context the future discovery of a universe other than our own. The Asimov view seems compelling to me: We know of one universe, which might be unique. We can be sure that there are either no other universes or many others, but not two. In the absence of evidence, I vote for no others. BTW: Concening the laws of physics elsewhere in our universe or in another universe, I see no reason to vote for laws of physics elsewhere being different from those accepted by mainstream science. Perhaps some evidence might be discovered which supports the notion of different laws elsewhere (as opposed to improvements). Until there is such evidence, it seems irrational to consider the possiblity likely.