He goes on to say many things that are well known; that we look for corroborating evidence, that we're not good at hearing or processing facts that are against what we think. He cites a scientist, however, that takes this a step further and puts the whole thing together; that we don't reason in order to objectively understand the world but in order to persuade others.
Now, I'd say that it's also to persuade ourselves, but I'll get back to that in a moment. What struck me is that knowledge is mostly ornamental; our abstract reasoning is subservient to our social reasoning. As Lehrer puts it so masterfully:
"Instead, the function of reasoning is rooted in communication, in the act of trying to persuade other people that what we believe is true. We are social animals all the way down."
This seems to me to be very deeply connected with the notion of cognitive dissonance and identity. For those who haven't read my previous posts, I was suggesting that we rationalize what we do and look for evidence in order to do so because it's what regulates our identity; that acting in a totally "rational" would bring about symptoms resembling schizophrenia* Think about a computer generated actor that always makes the "optimal" choice; it would confuse the hell out of us as it would change behaviors without any warning or visible precedent. The body must fight off what is foreign and so must the mind.
This is why I say that we also look for corroborating evidence to persuade ourselves. Really, though, I didn't just bring this up to one-up Mr. Lehrer; I wanted to say that persuading others and persuading ourselves are one in the same. If we find corroborating evidence in order to construct a story for others and do the same for ourselves, then it seems fair to say that narratives are the primary way in which we perceive the world. Our instinct, when we debate with others, is to try to tell a great story; no different than when we seduce or entertain and also no different than when we make sense of our own situation by constructing an identity.
The story we tell ourselves and the stories we tell others are two sides of the same coin.
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*If anyone reading this deals with people who have serious problems such as Schizophrenia, I apologize in advance for anything presumptuous I may be saying. This blog is a loose network of working hypotheses, many of which will turn out to be extremely silly.