According to the best-known telling of the tale, Hippasus, a Pythagorean of the fifth century b.c., was drowned in the sea by his fellow philosophers while on a fishing voyage. Hippasus had disclosed a secret that, if made public, risked destroying the credibility of his school’s commitment to a cosmos governed by perfect mathematical harmony: The relationship between a diagonal of a square and its side cannot be represented as a ratio — it is “irrational.” This legend sets the stage in Irrationality: A History of the Dark Side of Reason, Justin E. H. Smith’s urgent missive to a Brahmin class wracked with anxieties about a world that seems to have lost its grip on reason.
Smith, a philosopher of science at Paris Diderot University, is motivated by an urgent sense that a milestone reassessment of the Enlightenment’s legacy, and of the role of reason in public life, is underway in the United States and elsewhere. The emergence of prominent public voices with open counter-Enlightenment sympathies — such as Steve Bannon and Peter Thiel — and the resurgence of jingoistic populism are good reasons to take notice. So too is the fierce battle being fought between self-styled defenders of the open society, such as Steven Pinker and Jordan Peterson (however tenuous their grasp of the philosophies they claim to champion), and heirs to the left-wing critical tradition that views Enlightenment ideals as instruments for the powerful to oppress the marginal.
Smith is troubled by lapses into self-destructive unreason — the erosion of trust in institutional medicine, the corrosion of political discourse, progressivism’s increasingly draconian tactics of self-policing, and the global resurgence of nationalist mythology — which he attributes to a crumbling commitment to liberal democracy. He is wary, however, of uncritical defenses of the Enlightenment’s legacy, both because making final judgments about its nebulous history is prohibitively difficult, and because champions of Enlightenment rationalism often voice facile notions about the history of Western liberalism and its rivals. Smith criticizes Peterson, for example, for failing to notice that the murderous Communist regimes of the twentieth century bear an important genealogical relationship to liberal democracies. Irrationality paints an alternative picture.
In Smith’s hands, Hippasus’ tale is a clever illustration of a subject that is by nature tenebrous and resistant to investigation. What makes it a rich parable of the history of reason is not only the familiar story of rationalism degenerating into violence, but the many meanings of “irrationality” present within the story — mathematical incommensurability, philosophical bankruptcy, religious fanaticism. The murder of the hapless Pythagorean serves as a specimen of the intrusion of unreason into just those spaces from which it is thought to have been expelled. Rationalist projects, in Smith’s telling, are self-confounding. Rational investigation uncovers inconvenient realities, undermining the assumptions upon which such projects justify themselves. As the German thinkers Theodor Adorno and Max Horkheimer argued in Dialectic of Enlightenment (1944), rationalist projects predictably degenerate into self-mythologizing effervescence. Ultimately, the meaning of “reason” is itself fraught with unresolvable ambiguities.
From these themes, Irrationality pieces together a portrait of unreason, in which the relationship between rationality and irrationality is not one of simple opposition, but of two sides of a whole pushing and pulling on one another in a “dialectical relationship between Enlightenment and counter-Enlightenment.”
For better and for worse, Smith outpaces the dead-end squabbles of the hucksters who pass for this decade’s public intellectuals. Yet to describe his project, as he does, as illustrating the dialectic between reason and unreason — and how unreason reigns precisely when we think we have eradicated it — sells it short. For there are insights developed in Irrationality that cut much deeper, in ways the book is reluctant to reckon with.
Although Justin E. H. Smith is an excellent essayist and cultural critic — a voice of authority and wit, gifted with a rare talent for unearthing and formulating the most interesting questions hiding in less-appreciated details of intellectual history and pursuing them into unexpected places — it’s a challenge to summarize the book’s arc in brief. More like an anthology of essays than a single cohesive work, the book gradually offers a conceptual inventory rather than a linear argument as such. Each of the chapters contributes some insight that, Smith hopes, will form a larger tapestry.
The book’s first two chapters address ambiguities and inconsistencies in the structure of reason. The first chapter, “The Self-Devouring Octopus; or, Logic,” takes up the troubled history of logic and tries to give an account of its relationship to rhetoric. The conventional story of philosophy’s origin in ancient Greece is “that it was born at the moment debaters came to value truth, rather than victory, as the goal of debate,” marking the philosophers off from their ancient rivals, the sophists. And yet, the first philosophers, like the sophists, were accused by their peers of “making the weaker argument the stronger.” Philosophers, after all, were fascinated with logical fallacies, and for good reason. Syllogisms that dissolve or erupt into absurdity are bewitching.
Smith notes, astutely, that a great number of stand-by illustrations of fallacious reasoning — “You have whatever you have not lost; but you’ve never lost your horns, therefore, you have horns” — sound like jokes. He is interested in the fact that jokes, or “curdled” syllogisms, have a longstanding place in the philosopher’s war chest as rhetorical artillery. Smith calls the philosophical investigation of humor “gelastics,” after gelos, the Greek word for laughter. The theme that humor is the shadow side of logical inference runs throughout the book. He offers an affectionate examination of Slovenian philosopher Slavoj Žižek’s “self-Orientalizing schtick … in which he plays up his persona as a stock character from somewhere or other in the Eastern Bloc,” which “enables him to play at undermining the pieties of liberal democratic or bourgeois society.” Žižek’s “entire oeuvre will in all likelihood be remembered as an unusually compendious joke book.” The upshot of this approach to philosophy is a reprimand to thinkers such as Leibniz, who supposed that a sufficiently rigorous logical language might allow us to resolve any conflict through “computation.” This was never in the cards.
“The Self-Devouring Octopus” also offers a weaker investigation of the history of philosophical thought on the numinous and ineffable. Smith examines the mystical ecstasies that Plotinus’ biographer attributes to him, the “paradox-mongering” of ancient thinkers like Zeno, the insistence of the French postmodernists on concocting “statements that could not possibly be understood,” and the habit of rationalist movements to take on the character of cults. But these examples only hint at the limits of reason that mystical and religious experience discover in full, and Smith’s approach to those questions is a lacuna in his general theory. More on this later.
The second chapter, “‘No-Brainers’; or, Reason in Nature,” is a highlight of the book, entertaining alternatives to our commonplace notion of reason. Smith notes the ways in which the conceptual breadth of the Greek word logos is narrowed in translation — for example as “verbum” or “word” in the Gospel of John — then gives us an archaeology of some of the meanings we’ve left behind, particularly the meaning of rationality as a feature not of particular statements, or even of the human mind, but of the cosmos. A great deal of premodern thought takes for granted that nature is rational, not in the sense that the human mind is rational, but in that nature is ordered and intelligible. It is this sense of rationality that explains why the ancient Pythagoreans were so terrified by the “irrationality” lurking in the diagonal of the square — by the possibility that nature is not built out of intelligible harmonies, as musical intervals suggest, but has unresolvable discordances.
Smith puts this older conception of reason to work as a way to advance a theory of the rationality of animals. Animals, he says, “do not deliberate; they simply cut, as the saying goes, right to the chase.” They act without thinking, directly in accordance with their nature, and are in this sense “never, ever, wrong.” But that does not mean they are not rational, says Smith:
The attribution of reason to animals might not require any proof of higher cognitive function in them at all, for it may be that their “industry” itself is rational — just as the pocket watch is rational as a congelation of the reason that structures the world, as a “no-brainer.”
The intellectual history worked out here is illuminating and satisfying, but the important takeaway is the troubling fact that we might not know what “reason” ultimately means.
The next chapters, “The Sleep of Reason; or, Dreams” and “Dreams into Things; or, Art,” broadly address questions about the role of the imagination in reason, while “‘I believe because it is absurd’; or, Pseudoscience” offers a taxonomy of conspiracy theories and “alternative facts.” For Smith, the most dangerous varieties of pseudoscience are those that are, in essence, theories about social relations. To believe that the earth is flat and that this fact has been suppressed by a great conspiracy is “to be cut off from an understanding of politics as the working out of differences, through agreed-upon procedures, in a neutral public space.” That is, it is a commitment to the notion that our knowledge of the world has been hopelessly distorted by those in power, and that the appearance of democratic participation and public deliberation is merely a smokescreen. These chapters arrive at some of the same insights as Jason Josephson-Storm’s excellent The Myth of Disenchantment, a book that makes for good companion reading. Smith and Josephson-Storm both offer fascinating readings of science’s forays into mysticism as historical consistencies, rather than anomalies or contradictions.
In “The Human Beast; or, the Internet” and “Explosions; or, Jokes and Lies,” Smith addresses the reality-distorting possibilities of tools developed to advance human reasoning. Beginning with the remarkable story of Jules Allix, an eccentric nineteenth-century French socialist who promoted a fraudulent system for relaying messages through the animal magnetism of snails, Smith tells the story of the Internet as a history of disappointment. Unaccountable media empires have remained free of democratic oversight, and sinister algorithms have colonized our inner lives. A section on the activity of Russian trolls in 2016 offers some of the finest writing done on the subject, emphasizing the interest of foreign powers in our home-grown frivolities — “manspreading,” Rachel Dolezal, the meaning of the Confederate flag — as a means of accelerating our own self-destruction. “Acknowledgment of the complexities of reality is impossible, as social-media algorithms funnel our views into binarily opposed options, rather than inducing us to reflect and to doubt, or to ‘like’ in a qualified way.” Whereas we once hoped that the Internet would invigorate democracy, it is instead obliterating what is necessary for democracy’s proper functioning.
In the last chapter, “The Impossible Syllogism; or, Death,” Smith gazes at the final horizon. “There is no way out of it: every response to the specter of mortality can be criticized for its irrationality.” What can be said to a smoker who takes great pleasure in cigarettes about the fact that his decision to shorten his life is irrational? If we’re all hastening to the grave, what alternative avoids the appearance of absurdity? This is the final problem for the task of reason.
The book entertains so many questions and considers so many approaches that it’s easy to lose track of the primary argument until we return to it in the conclusion — with some disappointment. To argue that reason entails its opposite, as Smith does, is to suggest that both reason and unreason have fixed and stable identities, such that we can track the motion from one to the other. At his least ambitious, Smith seems to forget himself and to take for granted that what “reason” means is obvious. In the book’s preamble he takes inventory of the ways in which irrationality manifests at the level of the individual (dreams, affect, desire, intoxication) and of society (religion, storytelling, conspiracy theory, rhetoric), and he employs this rough-and-ready, conventional sense throughout. Rationality, we are told, is the opposite of these.
But Irrationality’s most promising moments suggest that the relationship between the two is not properly dialectical, but rather that both resist stable description. There might not be some obvious, easily agreed upon set of principles that we might use to define rationality and its opposite. One and the same thing might appear rational or irrational according to competing, incommensurable pictures of reason, because any such picture cannot be independently justified as rational. There might not be a clear difference, for example, in the rationality of deliberative democracy compared to other political arrangements more explicitly animated by imagination. And it’s not quite clear whether Smith means the stories about Plotinus, Zeno, and Žižek to prompt sober reflection on the risk that rational inquiry might lapse into unreason, or rather means them to blow apart the tidy boundaries between philosopher, sophist, and seer. Smith’s narrative strongly suggests the latter, but he never quite says as much.
In investigating religious practice, Smith claims that the kind of irrationality he’s concerned with is not the kind criticized by rational-choice theory, which seeks to understand why people don’t maximize their utility or choose the optimal outcome in a prisoner’s dilemma. Smith’s exemplars are religious renunciants. Rational-choice theory is a “broad homogenizing force” that “construes every individual as at least an aspiring voter, an aspiring homeowner, an aspiring member of a thriving nuclear family; it does not hold open the possibility of opting out of all this, of withdrawal, asceticism, or monasticism.” A monk opts out of this game of accumulating goods, as conventionally understood, in pursuit of some other goal.
Fair enough. It’s unclear, however, how Smith wants his readers to understand the categories of rationality and irrationality to be operative in the life of a monk — whether he takes the monk’s choice to be rational, irrational, or perhaps something else entirely. In one place, Smith tells us that “rational-choice theory has landed upon a default measure of rationality as profit seeking,” implying that what the monk has opted out of is simply this particular measure of rationality, in favor of some other. But a page before, Smith seems to offer the monk as an example of “situations in which agents seem to simply be acting independently of any concern to be, or to appear, rational.” So is the monk an example of unreason or not? Though Smith often treats reason and unreason as stable, definite opposites, here he seems unaware of describing one thing both ways.
Smith is sensitive to the fact that a certain meaning of reason presents itself as “order rather than conceptual articulation,” and that this notion undergirds and justifies religious practice. It is surely reasonable to desire order. Neither is it unreasonable, in principle, to desire enduring goods over ephemeral ones. Smith notes, too, that the traditions that prize renunciation engage with ideas of value absent from contemporary philosophy. It’s puzzling, then, to read a description of religious life as “acting independently of any concern to be, or to appear, rational.” Smith’s intention is to affirm the legitimacy of monasticism and mendicancy, but does so in a way that cedes the meaning of reason to the rational-choice theorists he takes to task. Smith is right to note that it would be vulgar to insist that Franciscan friars or Hindu ascetics surrender themselves to mendicancy in search of a payoff, but only because the rival value system from which the term is being borrowed is a vulgar one. Jesus insists that “whoever humbles himself will be exalted” and that “whoever would save his life will lose it.” Taken seriously, is the decision to pursue holy poverty obviously less rational than the decisions encouraged by some other set of values?
If we take for granted, as Smith seems at times to do, that philosopher and seer live straightforwardly contrary vocations, we would be scandalized to hear of Plotinus’ mystical experiences. Or is it possible that we have misunderstood something important about the ancient conception of philosophy? That Porphyry’s biography of Plotinus often seems to be describing a mystic, and that a number of other classical philosophers are portrayed after this fashion, unsettles us because of our assumptions of what the philosophical project entails. Porphyry, for his part, seems not the least bit ashamed of his teacher’s mysticism. Why should we not regard these as the hallmarks, to borrow an expression from Alasdair MacIntyre, of a “rival tradition” of rationality?
Smith’s account of pseudoscience, too, betrays an overeagerness to attribute to unreason what might well be rational under particular conditions or according to the terms set by a rival tradition of rationality. He argues that accepting the findings of institutional science or the prescriptions of institutional medicine requires something beyond rationality: It requires trust in those institutions. It’s perfectly reasonable to listen only to those voices that have earned one’s trust. Smith is right to take seriously how, for young-earth creationists, a particular set of religious values transcends scientific facts in importance, even while they purport to be debating more mundane matters of science. He distinguishes too hastily, however, between this mode of thinking and that of other pseudoscientific commitments. Smith argues that while certain communities of creationists act on an understandable commitment to a moral and metaphysical narrative, flat-earthers act on an unjustifiable belief in an insidious conspiracy so powerful that it undermines our ability to trust the most basic kinds of observation. The distinction is an interesting one, but it’s hard not to feel that it gives too little credit to the powers of distortion and deception at work in our time. Even if conspiracy mongering is a pathology (and it is), the sense that our perception of the world might be unreliable is not difficult to justify rationally.
Smith is right, too, to indicate the genealogical link between science and pseudoscience, but he flinches before following through to the conclusion these ambiguities reveal. Theodor Adorno’s scornful writing on newspaper horoscopes, reliant as they are upon the interplay of vagueness and confirmation bias, took issue with the lack of a theory of causation at work in pop astrology and with the credulity of the Americans who take it seriously. But for many influential theories of scientific explanation, this is exactly the job of science: to catalogue correlations between observations and to make predictions without trying to formulate ambitious theories of causation. The problem of separating science from pseudoscience remains fraught.
For the lengths to which Smith goes to rid us of our habit of using “Enlightenment” as a metonym for reason, and to impress upon us that rationality was first a “fetish of strange cults, like the Pythagoreans” before it was made the mythical foundation of the West, he is at times surprisingly inattentive to the lesson we learned from Pythagorean “irrationality” at the book’s opening. If rationalism, broadly understood, continually overturns its predecessors, it’s worth considering the possibility that this is not a fundamental feature of reason, but a feature of history. If attempts at ordering the world rationally always give way to unreason, or if rationalist projects find themselves unable to sustain their assumptions in an encounter with inconvenient realities, perhaps it’s because reason is never self-justifying. Smith might well note that theorists always define “reason” in contrast to some prior stage of unreason, to which reason offers a critique and answer. Reason, that is, is always reason as opposed to something else. What this thing might be is a historical variable: appetite, emotion, bare sense experience, faith, the tradition of Aristotle, and so on.
That reason cannot define itself without unreason is a problem for those of us who are committed to the idea of rational deliberation in the public arena — which is likely why Smith is reluctant to look this problem in the face. Smith has commitments — serious, thoughtful, and morally sensitive commitments — to a vision of politics that subordinates effervescence, mythology, and private interest to rational inquiry and careful debate. Is it obvious, after all of this, that reason really does offer us an alternative to mytho-politics? Irrationality begins with earnest anxieties about the future of deliberative democracy and ends by calling unreason “harmful,” “ineliminable,” and nothing more. The prospects for wrangling unreason into reason’s service look grim.
The story Smith tells precludes the possibility of a neutral space, anchored to some fixed point, from which to deliberate matters of public concern. A society that is at once cosmopolitan, open, and deliberative has unresolvable tensions at its heart. There will never be a language rigorous enough, as Leibniz had hoped, to solve conflict through computation.
We will never exhaust the supply of gurus with comforting solutions, and we aren’t in need of any more. In refusing to provide a road map for the future of the post-Enlightenment world, Irrationality instead offers something more precious: an alternative model for thinking publicly. Smith thinks uninhibitedly, with care, subtlety, curiosity, and moral seriousness. If it doesn’t salvage liberal democracy — perhaps it wasn’t salvageable to begin with — it may offer a way forward through the wreckage of our inner lives.