I sent this to a person I know (PhD in biology; has done some work with mouse models though it is not their focus). They said:
Yeah I don’t know... we definitely know more about mouse biology than people biology in a lot of ways. But can we make good predictions in mice? Not for a lot of things - living systems are still very complex and stochastic!
The sad fact is that we do not even understand mice very well. There is this old joke that can be paraphrased like this: if I were a mouse I could be cancer free and live forever, because it is so easy to cure these guys of diseases. As it turns out, however, this is not true. Within my field it was long gospel that caloric restriction (discovered some 100 years ago) can robustly extend mouse lifespan until studies in the last 20 years called this into question.
What the joke gets right is that we understand humans even less than mice. In fact, despite the controversies several interventions are relatively robust in mice when it comes to extending their life and health span (rapamycin, caloric restriction, growth hormone loss) while the evidence in humans is much weaker for these.
Delivering useful drugs, hopefully faster not slower than in the past, despite these issues will be an interesting challenge.
I've been thinking about why some domains have reached more definite, mathematized, and law-like models than others, e.g. the hard sciences of physics and chemistry vs the soft sciences of psychology and political science.
One hypothesis is that it's just much easier to experiment on, say, pendulums than on humans. Experimenting on humans is slow, it's hard to create very controlled conditions, IRB's severely limit what you can do. Theoretically, if I could experiment on a large number of humans for long periods of time without constraints on what I could do (something like Aperture Science?), then I maybe could harden the soft sciences.
A piece of evidence on this would be how good are our mouse models? There are substantially fewer restrictions on mice experiments and resultantly we do a lot of experiments on them (hence the "IN MICE" that ought to be appended to so many scientific result headlines). Maybe translation into humans is poor, and we're generally focused on humans so we feel like there's a lot we don't know, but if you just asked about how well we understood mice, actually we have a lot of really solid knowledge about psychology, metabolism, immune function, political economy, etc.
Can anyone familiar with mouse models in any domain comment on how good the mouse models are vs human models? 1x as good, 5x, 20x? Good = really solid predictions, we feel like we know what's going on, etc.
For that matter, the same question could be asked for drosophila.