Here's what I think: when you're born, you're assigned a brain like you're assigned a desk, a nice desk, with plenty of pigeonholes and drawers and secret compartments. At the start, it's empty, and then you spend your life filling it up. You're the only one who understands the filing system, you amass some clutter, sure, but somehow it works: you're asked the capital of Oregon, and you say Salem; you want to remember your first-grade teacher's name, and there it is, Miss Fox. Then suddenly you're old, and though everything's still in your brain, it's crammed so tight that when you try to remember the name of the guy who does the upkeep on your lawn, your first childhood crush comes fluttering out, or the persistent smell of tomato soup in a certain Des Moines neighborhood.