t’s the brain, after all, that devises experiments and interprets their results. How the brain perceives, how it makes decisions and judgments, and how those judgments can go awry are at least as important to science as knowing the intricacies of nonbiotic experimental machinery. And as any brain scientist will tell you, there’s still a long way to go before understanding the brain will get crossed off science’s to-do list. But there has been progress. A recent special issue of the journal Neuron offers a convenient set of “perspective” papers exploring the current state of understanding of the brain’s inner workings. Those papers show that a lot is known. But at the same time they emphasize that there’s a lot we don’t know.