One of the most common arguments raised by the rationalists against religious faiths is that many claims made by the religious tend to be unfalsifiable. Many times we hear or read arguments in the line of:
Under what conditions would you accept that there is no God / that there was no miracle here / that no supernatural beings showed their presence in this case? The problem of your thinking is that it is fail-safe. You have presupposed the answer to this problem and are willing to do whatever it takes to make this answer sound plausible.
I would like to ask a similar question here, though in the other direction. Under what conditions would a naturalist accept the incorrectness of their position? What conditions would be necessary to accept that the supernatural exists AND has influenced or does influence the natural?
In their advocacy of their worldview, atheists sometimes say:
The view that atheists believe that there is no God is incorrect. Atheism is the null hypothesis, not a claim. Atheists only claim that there is insufficient evidence to accept that there is God.
Thus it would seem that rationalists do not presuppose the lack of the supernatural.
However, quoting the Wikipedia article about Historicity and origin of the resurrection of Jesus:
Post-Enlightenment historians work with methodological naturalism, and therefore reject miracles as objective historical facts.
Furthermore, from another Wikipedia article, Naturalism (philosophy)§Methodological naturalism:
Steven Schafersman states that methodological naturalism is "the adoption or assumption of philosophical naturalism within the scientific method with or without fully accepting or believing it ... science is not metaphysical and does not depend on the ultimate truth of any metaphysics for its success, but methodological naturalism must be adopted as a strategy or working hypothesis for science to succeed. We may therefore be agnostic about the ultimate truth of naturalism, but must nevertheless adopt it and investigate nature as if nature is all that there is."
Schafersman asserts that "while science as a process only requires methodological naturalism, I think that the assumption of methodological naturalism by scientists and others logically and morally entails ontological naturalism", and "I maintain that the practice or adoption of methodological naturalism entails a logical and moral belief in ontological naturalism, so they are not logically decoupled."
This is a significantly different position. Here we presuppose the lack of supernatural influences on the natural and do everything it takes to interpret the reality in such a way that we may maintain the correctness of naturalism. In this view naturalism seems just as unfalsifiable as many religious claims. This brings the suspicion of naturalists' detachment from reality: regardless of what the truth may be and regardless of what is happening around them, they will keep believing in naturalism.
Superficially, it would seem to me that the correct, rational, open-minded position is to not presuppose the supernatural, but do not apriorically reject them either. Thus, whenever there is evidence for something strange happening, we should first seek natural explanations; but if we fail to explain the situation naturally, we admit the hypothesis that this even is/was supernatural, until natural explanations become available.
This view of mine has been challenged. For example:
I am concerned about the false dichotomy being offered by the question: The only options given are: either the child's recovery is completely understood by modern science, with many known examples OR the recovery was entirely due to a single appeal to God by his mother.
Furthermore, this view seems dangerously close to the (in)famous God of the gaps principle, rejected not only by rationalists and scientists, but by many theologians as well. Finally, it can be argued that the view I presented has not, historically, been useful in advancing knowledge.
But the only alternative I can see is to unfalsifiably, apriorically reject the supernatural in a most close-minded manner.
I must be missing something here.