When a claim or theory can be adequately defended against challenges and alternative explanations then that should be enough.
If a theory can do that then it has proved itself against critique, and this is as good as one can get.
There is no theory or criterion in a vacuum. But one can make use of that and turn it into an advantage. In that sense, if a claim can be defended succesfully against all potential challenges, then this means there is no better explanation available than that.
From an epistemological point of view, this is used by some approaches to epistemology and truth.
Another escape from the diallelus is critical philosophy, which denies
that beliefs should ever be justified at all. Rather, the job of
philosophers is to subject all beliefs (including beliefs about truth
criteria) to criticism, attempting to discredit them rather than
justifying them. Then, these philosophers say, it is rational to act
on those beliefs that have best withstood criticism, whether or not
they meet any specific criterion of truth.
In this sense, exposing a claim to more challenges makes us able to see its robustness or shortcomings easier. An important way a claim or theory is exposed to challenge is through being put to practical use, since then a claim is exposed to the plethora of diverse conditions that make up a given reality and its robustness against these becomes evident.
The Marxist criterion of practice
The question whether objective truth can be attributed to human
thinking is not a question of theory but is a practical question. Man
must prove the truth — i.e. the reality and power, the this-sidedness
of his thinking in practice. The dispute over the reality or
non-reality of thinking that is isolated from practice is a purely
and the Pragmatic theory of truth
Consider what effects, which might conceivably have practical bearings, we conceive the object of our conception to have. Then, our
conception of these effects is the whole of our conception of the
[..]What, then, is the practical difference of describing a belief as “true” as opposed to any number of other positive attributes such as “creative”, “clever”, or “well-justified”? Peirce’s answer to this question is that true beliefs eventually gain general acceptance by withstanding future inquiry.
are the same, in this respect.
Furthermore, jury systems, collective decision making and the like can be re-cast in that light as well, since these are also ways that a claim is exposed to more diverse challenges.
PS: Reasonable doubt, in this sense, is any (valid and justified) criticism of a claim or theory. If the claim can successfully defend itself against this criticism, it has proved itself beyond reasonable doubt.