It’s obvious that facts can be irrelevant; everyone knows that. But some facts which seem relevant are not. For example, let’s say you ask me whether or not women face gender bias in grad school admissions and I tell you that hummingbirds can fly backwards. This is an obviously irrelevant fact. But if I told you that data shows female applicants were significantly less likely than male applicants to be accepted to grad school, that would also be irrelevant. How could that fact possibly be irrelevant? It seems like exactly the kind of fact that could help answer the question. But the fact is at the wrong scale; its unit of analysis is wrong, which makes it irrelevant.
Great and quick read.