The glass floor and the meaning of rationality
In Toronto this past weekend for Ren's wedding, I got to visit the CN Tower, which claims the title of the tallest building in the world. (There are many different ways of measuring this; the most unambiguous thing that the CN Tower apparently gets to claim is that, including its antenna, it is the tallest freestanding structure on land in the world.)
The CN Tower has a small section with a glass floor. You can stand on it and look all the way down 342 meters (slightly under a quarter of a mile) to the ground.
The glass floor is perfectly safe, but absolutely terrifying. If it were a little cleaner, it would probably be even more terrifying. As it was, I could only bring myself to step partway onto it, and felt a startling rush of dizziness whenever I looked down. Gwen and Ernie were braver, and baby Claire, who doesn't know what we know about perspective and gravity, seemed to have no trouble at all.
Later on I saw a mean teenager standing on the glass floor and trying to drag his girlfriend out onto the glass with him -- teasing her, physically pulling her, grabbing at her, and all the while ridiculing her for her anxiety about stepping onto the glass floor. He seemed to consider her fear demeaning and a source of shame. She, meanwhile, was trying to escape being pulled out onto the floor and looked positively dismayed.
I realized when I saw this scene of cruelty that the mean teenager seemed to be holding onto a very tempting and persuasive notion of rationality. This is the idea that rationality is about having correct (or at least warranted) beliefs about the conditional probability of certain events with a significant survival value. In this concept of rationality, rationality is all about knowing things that could lead to justified decisions about whether things will kill you, for example. Ideally, the rational person would then use that knowledge to avoid getting killed, and to accomplish all kinds of explicit instrumental goals that have survival value (or, if you want to get all fancy and genetic about it, survival value for one's offspring).
Now on this account you can say something about how the frightened girl who didn't want to stand on the glass floor was being irrational -- and that's exactly what her boyfriend was on about. Over and over again. Because allegedly she didn't know that the floor was safe, or she didn't believe it, and she was, as they say, "seduced by her heart or led astray by her eyes" (Numbers 15:39). Or else she was irrational because she was influenced by her emotions into not taking advantage of her knowledge.
This story about rationality is appealing nonsense. First of all, it is nonsense because it seems to suggest that rationality has to be proven in a macho way by doing ostensibly risky things to show that one has lots of deductive knowledge about the risks. In this account, the rational person is constantly expected to subject herself to lots of weird science experiments (maybe firewalking, maybe holding the 300-pound pendulum up to her nose and letting it go without flinching, maybe drinking a mixture of precisely equal parts HCl and NaOH of precisely the same molar concentration, maybe lying on beds of nails with anvils on her stomach getting hit with sledgehammers, or whatever). It's cool that people do some of these things, but it isn't demanded of them by rationality.
Second, and more importantly, this mythical version of rationality denies that anyone has an inner life that matters or that is worthy of respect. It suggests that the inner life, and especially emotions, should always be subordinated to external goals, to decisions related purely to physical survival value. So in this account, whether something will kill you is a valid rational consideration, but whether you are afraid of it is not a valid rational consideration.
That's just not right, because it suggests that being killed or not killed has value or significance, whereas being afraid or not afraid has no value or significance. Anyone person can recognize that being afraid or not afraid -- like other kinds of experience and emotion -- has plenty of value and significance.
And indeed, feelings of fear are often rooted in things that are perfectly useful and adaptive even from a survival value point of view. The fact that we feel frightened when we see a sheer drop of over 300 meters immediately in front of us with no visible barrier to stop our fall is not "irrational"; it's an extremely adaptive reaction to the vast majority of situations in which human beings have ever encountered sheer drops of 300 meters in front of them. It's a reaction that is most often a lifesaving reaction. We should be happy, and proud of ourselves, that we are fearful of a sheer drop of 300 meters, just as we are fearful of other things that -- most often -- can easily kill us. Our reflexes and fears, for all that they can go awry, save us from death and serious injury every day. So we should be appreciative of them.
But more significantly, being afraid can be a rational reason not to do something. It does not have to signify that one has a false belief or a poor reasoning process. It does not have to be a proxy for some kind of physical danger. You can say "that glass floor is perfectly safe, stepping on it could not possibly injure me, and I don't want to step onto it because I feel frightened, and stepping onto it would make me feel uncomfortable" -- and your statement is a rational one. Rationality does not require us to feel no emotions, or to suppress our emotions, or to alter or subordinate our reflexes or conditioning in order to make our conditioned responses precisely appropriate to every single unusual circumstance we ever encounter. It's rational to have fears and it's rational to want to be comfortable even in situations in which those fears happen not to be protecting us from imminent physical harm.
And it's rational to want to be comfortable in general. It's rational to know that you have some kind of reaction to a situation and to avoid getting yourself into that situation, that you have a reaction to a stimulus and to avoid exposing yourself to that stimulus.
This is not to say that it isn't valuable to try to overcome fears or to try to rid one's self of phobias. Not all fear is adaptive or beneficial or desirable. It can be very rewarding to confront fears. But there is no virtue in doing so gratuitously or mindlessly. To demand that we act only on the strength of our knowledge about the outside world -- our knowledge of the glass floor, so to speak -- and not on the strength of our knowledge about ourselves, and of what makes us comfortable, would not be rationality. It would be denying the significance of the inner life.
David Friedman was once having a discussion with someone about Linus Torvalds. Linus claimed to have written Linux for fun. Someone else, perhaps captive to a narrow view of rationality, suggested that this was not a rational economic motivation. (Apparently, in that narrow view, the only rational economic motivation is making money. You have to show off by stepping on the glass floor for no other reason than that you can, and you have to show off by making money in the same way.) Friedman said that having fun "is a perfectly normal economic motivation" -- a view of rationality that respects Linus's humanity in a way that the teenager in the CN Tower seemed to have yet to have learned to respect his girlfriend's.
