Anthropic Principle

David Lindley, The End of Physics. The Myth of a Unified Theory, 1993. From Chapter 9, The New Heat Death

This is surely a generous way of thinking:  particle physicists have argued for the existence of all kinds of new particles in addition to the ones we know about, in order to allow supersymmetry or supergravity or superstrings to work, but proponents of the strong anthropic principle are multiplying whole universes in order to provide a home for us, and then, moreover, concealing those universes from us so that we can never see the extravances enacted for our benefit. This illustrates the basic dilemma in all this puzzling. We live in but a single universe that has been created, in which case we have to explain why that universe should have properties congential to our existence, or in one of an infinite variaty of universes, in which case the fact that we live in a congencial one becomes a tautology. The problem is that, by definition, we cannot know about universes other than our own; if we knew about them, they would part of our universe.