Your line of argument sounds reasonable and is frequently cited by
believers
of various types (UFO people, religious people, etc.) It has a big
problem,
however: There are an infinite number of non-refuted theories to explain
any phenomenon. (Proof: if there is a valid theory to explain something,
then
you can add any non-refutable hypothesis to it to derive another
non-refutable
theory.) I don't have time to deal with an infinite number of
non-refuted
theories. It there are two theories, one with hypothesis set "A" and one
with hypothesis set "A" + "B", where "B" is non-refutable, then I am
free
to ignore the second theory. "B" adds nothing to the theory, and the
predictive power of the theory "A"+"B" is identical to the predictive
power of "A". Therefore, the predictive power of the theory provides
no support for "B".
>From a practical standpoint, this means that you will have to show me
some evidence if you want me to evaluate a new theory. This habit of
thought is often referred to as "Occam's razor."