This is an issue that has been worrying me. As my pseudonym suggests, I try to treat neuroscience skeptically. I try my best to think seriously about claims made about the brain and check them against the facts, the evidence. This doesn't mean I reject everything: it means I accept only what the evidence supports. So why would a skeptic be worried? Well, my worry is that I might be being selectively skeptical. Am I only skeptical about certain types of claims? If so, is that a problem? More broadly, there are plenty of people out there who appear to be selective skeptics. My question is, does that invalidate their 'skepticism'? My answer is that a selective skeptic is still a skeptic, but a bad one. There are two different frames of reference here. If we focus narrowly on a particular claim, then if I'm skeptical about that claim, then I'm either right or I'm wrong, and the only thing that matters is the evidence in this particular case. In other words, if I were, say, a creationist who rejects all evolutionary science, I might still be right when I express skepticism about a particular evolutionary claim. And not just in the sense that even a stopped clock is right twice a day: I might genuinely uncover a problem with the argument. However, while a creationist "evolution skeptic" could be a genuine skeptic in a narrow sense, this selective skepticism is clearly not desirable. Suppose that I were to look skeptically at the claims made by one side in a certain scientific or public debate. I scrutinize their arguments and I find various problems; but for whatever reason, I never look into the claims coming from the other side of the controversy. In this scenario, I would have become, in effect, a partisan for the side I didn't criticize - even if this wasn't my intention. My selective application of criticism would have made me an uncritical defender of one side. Now in this scenario, I think I would still be a skeptic, but I'd be a bad one, because I am (so to speak) using my skeptical powers for evil. Instead if seeking truth wherever it is to be found, I would be digging up dirt and only flinging it one direction.