“The … truth about inflationary theory. The common view is that it is a highly predictive theory. … the inflationary paradigm is so flexible that it is immune to experimental and observational tests. First, inflation is driven by a hypothetical scalar field, the inflaton, which has properties that can be adjusted to produce effectively any outcome. Second, inflation does not end with a universe with uniform properties, but almost inevitably leads to a multiverse with an infinite number of bubbles, in which the cosmic and physical properties vary from bubble to bubble. The part of the multiverse that we observe corresponds to a piece of just one such bubble. … No experiment can rule out a theory that allows for all possible outcomes. Hence, the paradigm of inflation is unfalsifiable… Taking this into account, it is clear that the inflationary paradigm is fundamentally untestable, and hence scientifically meaningless.”
– Paul Steinhardt, Big Bang blunder bursts the multiverse bubble, Nature, 3 June 2014.
The quantum gravity theory which quantitatively predicted dark energy in 1996 (http://vixra.org/abs/1111.0111/) and predicts the low curvature of the early universe that’s normally attributed to “inflation” speculation, also predicts the electromagnetic coupling for the for same verified cross-section used in quantum gravity:
Testable alternative to inflation theory: quantum gravity theory provably flattens early spacetime curvature as observed, without introducing any epicycles, please see http://vixra.org/abs/1111.0111 and other papers at vixra, e.g.