In biological sciences we have to integrate multiple kinds of evidence — in vitro (or in larva? — in the mask) lab experiments, animal models, randomized contro

In biological sciences we have to integrate multiple kinds of evidence — in vitro (or in larva? — in the mask) lab experiments, animal models, randomized controlled trials in humans, descriptive statistics of human populations, in silico simulation, etc. — because they all have their advantages and disadvantages. Lab/in vitro models are great because they allow for tightly controlled conditions and are clear tests of mechanisms, but they might not represent real-world conditions in living human beings in our social context, with all of the attending quirks and nuances. Animal models are great because they're a complete organism upon which we can still do a whole range of controlled experiments which we can't do in people. But they're not human beings, so there could be differences there. And we can't control them as closely as e.g. an experiment with a few cells or a few viral particles. etc. etc. When all the evidence seems to be pointing in roughly the same direction, I think it's fair to say we know something. That appears to be the case with masks limiting the spread of Covid, even if the confidence intervals on the randomized controlled trials are large. That's very different from "little, if any benefit".