I got to thinking today about that old myth that we only use ten percent of our brains, and it occured to me that evolutionary thinking is actually pretty useful for combatting superstitions other than the religious sort. How long, after all, would this notion have stuck around if people thought about it in Darwinian terms? The brain, after all, is a pretty “expensive” organ, in evolutionary terms. How much sense would it make for the vast majority of us to be lugging around a couple of pounds of highly complex but totally unused cells? (The glimmer of truth in there is that we don’t use all of our brain at any given time, in the same way that most of our muscles aren’t in use for a lot of the day.)