The two articles I want to discuss today are fascinating, for they raise a problem that’s now vexing many scientists (especially physicists)—the problem of testability. (Thanks to reader Mark H. for calling my attention to them.)

It all goes back to the philosopher Karl Popper (1902-1994). Popper’s views about what made a theory “scientific” were immensely influential. They’re summed up in the Wikipedia piece on him:

A theory in the empirical sciences can never be proven, but it can be falsified, meaning that it can and should be scrutinized by decisive experiments. If the outcome of an experiment contradicts the theory, one should refrain from ad hoc manoeuvres that evade the contradiction merely by making it less falsifiable.

In other words, a theory that can’t in principle be shown to be wrong isn’t a scientific theory. But I disagree with that characterization, and the one from Wikipedia, in two ways.  First, a…