Biologist here. Biologists don't try to predict whether a drug will have side effects before giving it to humans. They simply give it to mice. If we do have som

Biologist here. Biologists don't try to predict whether a drug will have side effects before giving it to humans. They simply give it to mice. If we do have some strong reason to suspect it might be harmful to humans, we might do a primate trial, but usually not as those are expensive. People do make statements like "Drug X has target Y, so its side effects should be limited to A, B, and C", but no one takes those claims seriously. It's too hard to predict what a drug will do, and in fact drugs are frequently used in practice without any knowledge of mechanism of action. The point is that biology is fundamentally empirical here, because in complex systems it seems that rationalism/theory is not that useful. > Economics is hard because you can't do repeated trials. Yes. The problem is that they pretend they can predict results of interventions when they demonstrably cannot. Economists are simply used to justify policy decisions made on some other basis.