Smith teaches philosophy at the University of Paris. This book is more of a survey than a history. He has chapters on irrationality as it relates to logic, nature, dreams, art, myth, pseudoscience, humor, the internet and death. He occasionally discusses the fact that the American president is a dangerous buffoon. (Or, as a New York Times columnist put it so well: “The most powerful country in the world is being run by a sundowning demagogue whose oceanic ignorance is matched only by his gargantuan ego”. Or, as a Washington Post columnist concluded: “If he can’t argue that he has delivered prosperity, all that remains is the single most repugnant human being to ever sit in the Oval Office, befouling everything he touches”. But back to the book.)

Smith argues that the difference between rationality and irrationality often depends on one’s perspective. For example, is it rational or irrational to concern ourselves so much with the future when we’re all going to die anyway? It depends on what our goals are. His principal thesis is that “irrationality is as potentially harmful as it is humanly ineradicable, and that efforts to eradicate it are themselves supremely irrational” [287].

It’s an interesting book, but I’d say the first part of that last sentence didn’t need to be proved (irrationality is harmful, both actually and potentially, and will never be eliminated) — and that Smith fails to prove the second part (that efforts to eliminate irrationality are supremely irrational).

This is from his chapter on death and one of the best passages in the book:

… what lifted the soldier out of his foxhole was not his faculty of reason, but rather something deeper, something we share with the animals, which the Greeks called “thumos” and which is sometimes translated as “spiritedness”. It is a faculty that moves the body without any need for deliberation. It is like something that propels us when we are driven by desire, when we dive into a mosh pit or into bed with someone we don’t quite trust. It is something to which we are more prone when we are drunk, or enraged, or enlivened by the solidarity and community of a chanting crowd.

These manifestations of irrationality, it should be clear, are, as he saying goes, beyond good and evil. Life would be unlivable if they were suppressed entirely. But to what precise extent should they be tolerated or, perhaps, encouraged? It will do no good to say flatly that they should be tolerated “in a reasonable balance” or “in moderation”. For the ideal of moderation is one that is derived from reason, and it is manifestly unfair to allow reason to determine what share it should itself have in human life in a competition between it and unreason. So if we can neither eliminate unreason, nor decide on a precise amount of it that will be ideal for human thriving, we will probably just have to accept that this will always remain a matter of contention, that human beings will always be failing or declining to act on the basis of rational calculation of expected outcomes, and that onlookers, critics and gossipers will always disagree as to whether their actions are worthy of blame or praise.

The speeder and the duelist and the others seem guilty of no failure to correctly infer from what they already know, in order to make decisions that maximize their own interests. Rather, in these cases, there is a rejection of the conception of life that it must be a maximization of one’s own long-term interests in order to be a life worth living [263-264].