“I can’t believe how closed-minded he is.”

We might conclude that the person who says this is pretty open-minded. After all the more open-minded one is, the less one is able to believe how closed-minded other people can be, right?

Not necessarily. For three reasons, it's easier to detect others' closed-mindedness than one's own. First, it's more fun and profitable to notice other people's faults. Second, we tend to diagnose others by our personal standards. ( “He's closed-minded because he disagrees with me.” ) Third, seeing through one's own closed-mindedness defeats its purposes--and yes, closed-mindedness does have purposes.

When we're thinking of closed-mindedness as a vice, we tend to follow a four-step recipe for convincing ourselves and others that we are exempt from that vice.
 
Exempt by contempt recipe:

1. Show contempt for another person’s closed-mindedness.

2. Thereby deem oneself an expert about who is and is not closed-minded.

3. As an expert, do a conclusive self-examination finding a total absence of closed-mindedness.

4. For added effect, return to step one, showing greater contempt.

The Exempt by contempt recipe can be applied to other so-called vices, such as self-deceptiveness, ego, and self-indulgence (each of which also has its virtues). The recipe is consistent with what Freud called "projecting," finding in others the traits one is loath to see in oneself. But here's the rub: Not every critique of others is a projection. Sometimes they really are more closed-minded than you.

Exempt by contempt is a weak argument in defense of one’s relative virtue.  Just because one can spot someone else’s vice but not one’s own, it doesn’t necessarily mean one don’t have that vice. Still, Exempt by contempt is remarkably persuasive. In politics, it’s key to mudslinging, that reigning strategy for persuading voters of one’s relative virtue.

Notice  Exempt by Contempt as it flies by in your thoughts and your conversations. You'll be more discerning about criticism of yourself and others.