Passionate Thinking

A friend of mine once said "What the facts will not support conviction will carry." It is almost scary how true this is. It would seem that at some point the shear weight of facts would have some sort of influence but conviction seems to be an almost irresistible force. Conviction eliminates the inconvenience of listening. When you already know everything about everything it does away with the trouble of having to hear anything new or different. Conviction eliminates the need for thinking. When you already know everything about everything you can pass on gathering facts and evaluating information. Conviction eliminates all that messy relationship stuff. Why bother to get to know people when you already know who they are, how they think, and what they are up to. I have recently been identified by a person with great conviction as part of a vast conspiracy. The advantage here for this person was that they were completely spared the necessity of gathering facts or actually talking to the people involved. Conviction really speeds up the process.
I have another friend that commented that many of the interpersonal problems we have individually and at societal or even international levels happens when we get a case of "hardening of the categories." Conviction eliminates the need for thinking and hardening of the categories puts people in predetermined sub groups of good and bad.
How much harm has been done because people just knew what was going on and what people were like without ever taking the time to find out if any of their perspectives could be supported by facts?
In my case, I am sleeping pretty well while this other person is lying awake at night wondering what I am up to.