Christianity is heading for a full allegorization

[Spongebob]

We have two hypotheses:

1. Ice cream trucks cause drownings.

2. Both ice cream trucks and drownings occur mostly in summer.

So what we need is an observation that will distinguish between these two hypotheses.

The most obvious one would be to rent a bunch of ice cream trucks in the winter and see if drownings increase then as well. Even better, do this at various different times of the year and in various locations. Then see if the correlation persists.

You are right, the correlation is primarily observational.  But when there is more than one active hypothesis (and there almost always is), the key is to find some setup where the two hypotheses give different predictions and see which one is wrong.

This is yet another reason why a single experiment is not enough to overthrow a theory. The experiment needs to be conducted in a variety of situations to explore when the observed correlation (or lack) is there.

I think the basic problem is the expectation that science will give a 'mechanism' for all 'causes'. And that is simply false. In fact, the whole idea of 'mechanism' assumes a metaphysics that is very likely to be wrong.

This was a very concise explanation, but I would like to expound on the last statement, the idea that explaining a mechanism assumes metaphysics.  I'm not sure how you mean that so I would like to hear more.  What I do know is that providing a mechanism for any theory does not necessarily validate the theory.  What it does do is provide a context from which we can evaluate how likely the theory is valid.  If a theory or hypothesis has a very weakly devised mechanism, then it's reasonable to discard that idea.

An example:  acupuncture therapy.  There are very detailed descriptions of the mechanism for how acupuncture works, so this should work to make the hypothesis sound.  But the mechanism relies heavily on the existence an energy called "chi" and the precise location of important energy pathways, sometimes called meridians.  The existence of both chi and meridians is theoretical itself and cannot be assumed to be valid, so assuming this in a mechanism which is assumed to explain how acupuncture works is not valid.  Also, no scientific experiments conducted to evaluate the flow of energy or release of endorphins due to the insertion of needles (using as many blinds as possible) have failed.  So the mechanism in this case is practically useless.  However, in the case of something like the mechanism of how the covid 19 virus works to invade cells has helped to develop vaccines and other medications that have been successful.  So in this case the mechanism wasn't crucial in validating theories but was helpful in developing treatments that work because the theories are accurate. I also like how most explanations of acupuncture state how the practice is based on "Traditional Chinese Medicine", which intentionally invokes thoughts of ancient and mysterious practices when in fact, TCM is not ancient at all, nor particularly mysterious.  Or something like that.