Idealistic lawyers and idealistic scientists often describe themselves as engaging in a search for truth. The scientists follow the scientific method. They state their hypotheses, describe the ways they test them, present their findings — and wait for another researcher to prove them wrong. Lawyers’ practice is built on the idea that the best way to shake the truth out of a complex dispute is for advocates on each side to argue it, as vigorously as they can, in front of an impartial judge or jury. These approaches work more or less well on their own. But when a legal...