John Nash On Thinking Rationally As Dieting

In A Beautiful Mind: The Life of Mathematical Genius and Nobel Laureate John Nash (Simon and Schuster, New York, 1998, p. 351), Sylvia Nasar writes:

Nash has compared rationality to dieting, implying a constant, conscious struggle. It is a matter of policing one’s thoughts, he said, trying to recognize paranoid ideas and rejecting them, just the way somebody who wants to lose weight has to decide consciously to avoid fats or sweets. [link added]

This is a particularly perspicuous analogy for Nash to have made. For the failure rates of diets provide one grim indication of the difficulties of the task at hand: thinking ‘rationally’–whatever that may be, and for the time being, I’m going to elide the difficulties of providing an adequate definition–is almost destined to fail for most people. We get on the wagon, we fall off, we get back on again, straining and striving, only to find out at the most inopportune of moments that our reserves of resilience have run dry, and that we have relapsed.

This slip back down the slope, back to where the rock waits for us, waiting to be pushed back up the slope, is suggestive in more ways than one.

First, the ultimate objective, a lower weight, a more rational mind, remains a contested goal: we might not want to get to the top. We have received conflicting signals about the desirability of it all. Sure, a lower weight will transform some statistics pertaining to my health in a favorable manner, but perhaps my aspiration for it is grounded largely in vanity and low self-esteem, in a failure to accept myself for what I am. And as the Underground Man suspected, thinking rationally isn’t all it’s cracked up to be either–especially if it ends up excluding vast domains of experience and reflection. Or, as another master of suspicion might have wondered: Why should we think ‘rationally’? Who wants us to do so? What is in it for them? Perhaps, I could define ‘rational’ in a way that is more suited to the achievement of ends that I have freely chosen for myself; if I have to ‘overcome’ myself, let me do so my own way, driven by my own needs and wants.

This further suggests then that the dieting and reasoning Sisyphus might, while only partway up the slope, let go of the rock himself. Not only are the doubts about the destination overwhelming, but so is the promised relief of the downhill journey back to the rock. We should not forget that Sisyphus has the  pleasures of an easier task ahead of him now; sure, the agonizing task of pushing the rock back up the slope awaits, but for now, sweet release awaits. (Let us not forget the pleasures of the early stages of the ascent too.)

Perhaps rationality, like dieting, only ‘works’ if it’s not seen as such; if it’s not a program of self-improvement, but an ongoing way of life. That ongoing way requires constant decisions and choices, each consuming considerable cognitive resources; pitfalls abound along this path. Failure is more common than success; as it should be, given the ambiguities noted above. And much as we use the data pertaining to the failures of diets into our reckonings of what a ‘good weight’ is, and what ‘success’ in a diet amounts to, we should reconfigure our notions of the desirability and possibility of rationality as well.