Rather, their most critical functions were designed first, and their less critical functions were added on like bells and whistles as the millennia passed, which is why the really important parts of your brain (e.g., the ones that control your breathing) are down at the bottom and the parts you could probably live without (e.g., the ones that control your temper) sit atop them, like ice cream on a cone. As it turns out, running with great haste from rabid wolverines is much more important than knowing what they are.
