Earlier quoted context omitted.
> If you do not have evidence that X works, or the evidence is ambiguous, your conclusion is the null hypothesis (that X doesn't work) No??? This is what having a prior is for. In this case, the prior was the mechanistic model which told you with reasonable confidence that masks would work in the slices of worlds where the primary mode of transmission was one mitigated by mask-wearing. We do not in fact live in a sta…
> No??? This is what having a prior is for. In this case, the prior was the mechanistic model which told you with reasonable confidence that masks would work in the slices of worlds where the primary mode of transmission was one mitigated by mask-wearing. Yes. I'm incorporating a prior. Read what I wrote at the top of the thread: every medical intervention that has ever failed a trial has had a biologically plausible…
Yes, this is reasonable, in the general case, absent a specific example to examine. However, masks do in fact work to prevent the spread of certain kinds of disease, based on both obvious mechanistic reasoning and on actual experimental evidence to that effect. Making the affirmative claim that masks would not work against covid (at the time) would have been ignoring or denying the non-trivial possibility that they would work quite well (or work poorly, but working poorly is still working on the margin).