Politics/Economics: How would you know if you were wrong?

It’s human nature to want to be right; in fact, our brains seem to need it. As a result, it’s a very natural response to grant ourselves a great amount of leniency when we’re wrong (or to rationalize it away), whereas we like to nitpick our opponents in ways that magnify their mistakes. (I was only ten minutes late to the appointment! Geez, why was she so mad? ... Hey, why is that idiot doctor keeping me sitting here ten minutes, the bastard?!)

However, rationalizing mistakes away in the political and economic arenas doesn’t seem to be the best course of action, when lives and livelihoods are at stake. How do you fight against the human urge to sweep mistakes under the rug when it comes to your own misinterpretations of fact, or those of the authorities you most follow?

This also happens in Religion, for example, but I’d like to stick to areas where assertions are a little more measurable. For instance, we could go ‘round and ‘round on whether or not this interpretation of the recent East Coast earthquake is correct (although it’s an interpretation that serves the speaker). A better example of what I mean is an assertion that the Reagan tax cut in 1981 is what spawned the dot-com boom of the late 1990s (and not, actually, advances in computer technology such as the small PC and TCP/IP). Going to such great lengths to rationalize apparently unconnected events to enhance one’s own political or economic goal is much easier than admitting your idea or pet dogma ended up being hooey.

How do you keep yourself in line and away from illusion? In short, how do you know when you’re wrong, and not “right” for a BS reason because of your brain’s need to feel good about itself?