In my philosophy of mind class, the very first article in our course reader was not a philosophy article at all, but rather a 30 year old piece by a couple of psychologists. * It discussed just how wrong many people are when it comes to understanding their mental processes.
In one sample experiment, they presented people with four identical white shirts, and asked which one they liked the best. People invariably picked the one on the right. When asked why, they gave every answer but the fact that it was on the right, and acted as if the researchers were crazy for suggesting that perhaps that was the reason.
They give several other examples, but that one alone is enough to make me stop and go "WTF?"--and bug the shit out of me. Bugs me bad enough that I tend to babble about it in ordinary conversations.
You see, we're told from a young age that it is important to "know thyself," and the standard thinking on that issue seems to be that once you've imbibed the wise maxim, it's just a matter of applying it by being mildly more conscientious than you used to be. Not so simple it turns out.
Or: a few weeks ago, I mentioned becoming somewhat obsessive about honesty. Honesty, it would seem, involves telling people why you're really doing things, not the reasons that will make them think well of you. And of course, that's absolutely mandatory, because you know why you do things. Except you don't.
And it gets even worse, as the folks at Overcoming Bias tell me that there's all kinds of fakeness people people engage in, starting with fake morality (an obvious enough threat I can deal with looking out for), but also fake optimization criteria, explanation, justification, causality, and even fake selfishness. The last one has got to be the buggiest of them all, because it seems like a fairly safe way of avoiding self-deception is to think of what selfish motives you might have for doing something, and take seriously the idea that they might be your real motives. However, the arguments in the fake selfishness post suggest it's actually easy to attribute selfish motives to yourself incorrectly.
How does one live with all this? I think I need to start by telling myself that I needn't go overboard with all this skepticism about myself, given that it's based on the idea that I do know a few things about myself. However, knowing that's of little comfort if I don't know nearly as much as I used to think. To answer questions about motives with an insistence that one doesn't know risks a kind of self-deception in itself if one does, in fact, know. A compromise strategy would be present any possibly risky claims about why one did something as only your best guess. Sure to annoy people you talk to, but may be the most you can do, until you've done far more towards obeying the old slogan than most people ever dreamed was necessary.
*Richard E. Nisbett and Timothy DeCamp Wilson. "Telling More Than We Can Know: Verbal Reports on Mental Processes." Psychological Review May 1977, p. 231