Joshua Rothman in The New Yorker:
I met the most rational person I know during my freshman year of college. Greg (not his real name) had a tech-support job in the same computer lab where I worked, and we became friends. I planned to be a creative-writing major; Greg told me that he was deciding between physics and economics. He’d choose physics if he was smart enough, and economics if he wasn’t—he thought he’d know within a few months, based on his grades. He chose economics.
We roomed together, and often had differences of opinion. For some reason, I took a class on health policy, and I was appalled by the idea that hospital administrators should take costs into account when providing care. (Shouldn’t doctors alone decide what’s best for their patients?) I got worked up, and developed many arguments to support my view; I felt that I was right both practically and morally. Greg shook his head. He pointed out that my dad was a doctor, and explained that I was engaging in “motivated reasoning.” My gut was telling me what to think, and my brain was figuring out how to think it. This felt like thinking, but wasn’t.
The next year, a bunch of us bought stereos. The choices were complicated: channels, tweeters, woofers, preamps. Greg performed a thorough analysis before assembling a capable stereo. I bought one that, in my opinion, looked cool and possessed some ineffable, tonal je ne sais quoi. Greg’s approach struck me as unimaginative, utilitarian. Later, when he upgraded to a new sound system, I bought his old equipment and found that it was much better than what I’d chosen.
In my senior year, I began considering graduate school. One of the grad students I knew warned me off—the job prospects for English professors were dismal. Still, I made the questionable decision to embark on a Ph.D. Greg went into finance. We stayed friends, often discussing the state of the world and the meta subject of how to best ascertain it. I felt overwhelmed by how much there was to know—there were too many magazines, too many books—and so, with Greg as my Virgil, I travelled deeper into the realm of rationality.