Great calamities compel us to revisit the complacent assumption that tomorrow will more or less resemble yesterday. In 1919, shortly after the end of World War I and in the midst of the viral pandemic that followed, the French poet Paul Valéry remarked that “we civilizations know now that we are mortal.” The presumptuousness of speaking in the name of civilization was revealing: it showed that what Valéry feared was the loss not simply of health, wealth, or domestic tranquility but of the very idea that man is in control of his destiny—the defining assumption of civilization.

Today we find ourselves in the midst of another great calamity. Once again we are compelled to ask whether our rational faculties are capable of coping with a virus about which we know far too little. The measures we think we need to take to keep untold numbers from dying are themselves so painful in terms of damage to our livelihoods that we wonder whether they can be sustained.

In short, we find ourselves on the horns of a tragic dilemma, similar to that of Antigone, who faced a choice between burying her brother and breaking the law. Being forced to choose between competing goods or commandments is the essence of tragedy. In normal times we can often strike a reasonable compromise, but in exceptional times the necessity to choose can become cruelly stark.

Calamity, in short, reminds us of what another Frenchman, the political thinker Raymond Aron, said we tend to forget in the long intervals between disasters, namely, that “History is tragic.”

Tragic reversals of fortune are all the more devastating because they are rare and therefore take us by surprise. Rational man is an optimist by nature: he believes that all unknowns can be known sufficiently to reckon with them, hence that impenetrable uncertainty can be reduced to calculable risk (to borrow a distinction from the economist Frank Knight). Every new calamity reminds us that such optimism is an unearned luxury and that rationality, like prayer, is a mere entreaty addressed to the inscrutable universe, which at times, as now, can place us in a double bind from which there is no easy exit.

As a young man, the German philosopher Friedrich Nietzsche wrote The Birth of Tragedy, an overheated outgrowth of his philological investigations into the origins of Greek tragic drama and his idolization of Richard Wagner. What matters to us is his approach, not to the narrow question of how Attic tragic drama came to be, but rather to the broader question of the recurrent rebirth of tragedy.

Tragedy is reborn every time the trickster Fate pulls the rug out from under us, every time our finely furbished reason fails to rescue us from chaos. The terra firma on which we had confidently taken our stand only moments before reveals itself to have been nothing more than a flimsy mantle camouflaging an abyss.

No longer supported by the unquestionable solidity of familiar routine, we stumble. We lose our bearings and begin to forget that anything resembling normality ever existed. We settle into abnormality even though we know it cannot last: wars end, whether by victory, defeat, or exhaustion; famines cease, whether because the rains, return or everyone dies of hunger; quarantines are lifted, whether because a vaccine is found, or the disease runs its course and the survivors have buried all the dead—or, more ominously, because people will starve if they cannot work, even if returning to work will expose them to death by disease.

This is the stark tragic dilemma we now face.

The kernel of Nietzsche’s conception of tragedy was that within every well-regulated order lurks the potential for chaos. The symbol of order is Apollo, the god of the sun, which rises predictably day after day. Dionysus, by contrast, presides over the sources of chaos: intoxication, lust, violence–and disease.

We moderns are perhaps more vulnerable to the irruption of chaos than were the Greeks, who even within their Apollonian order maintained forms and rituals to remind them of Dionysus’s omnipresent potential for disruption.

To be sure, we do not lack for recent examples of civilizational tragedies, as Valéry’s remark suggests. World war, genocide, famine, financial collapse, looming climatic disaster, weapons of mass destruction—everyone now alive harbors at least some knowledge of these things. Yet between crises, we labor mightily to keep such knowledge at bay.

Our faith in rationality today is not quite as robust as it was at rationalism’s inception in the seventeenth century. At that time, it was possible for some serious thinkers to believe that “all is for the best in the best of all possible worlds”—the very Leibnitzian faith that Voltaire mocked in Candide, by raising the specter of Lisbon’s destruction in an unforeseen earthquake.

Not only is our faith less robust; it is also divided into competing sects. Neoliberals hold that the rationality of the market, guided by an invisible hand, transcends that of its participants, who know not (and need not know) what they do. Social democrats acknowledge the danger of accidents but wager that their probability can be calculated with sufficient accuracy to insure against them. Socialists trust that contingency can be subdued once decision-making is wrested from the owners of capital and vested instead in an enlightened, universal class of emancipated laborers.

Adherents of each faith, though shaken by Covid-19, attempt to buck themselves up by anticipating the triumph of their own version of rationality once the virus is finally conquered. Socialists take it for granted that the rapid spread of the disease proves once and for all that globalized capitalism is itself a self-destructive scourge. For neoliberals, the bungled responses of governments of all stripes demonstrates yet again that human welfare cannot be entrusted to human hands; impersonal market forces will push us where we need to go. Meanwhile, social democrats trust that when all is said and done, both capitalists and anticapitalists will see the light and agree that compromise is for both the least bad option.

Some find these vestigial rationalist faiths reassuring, but others, thrown bodily into a realm of radical uncertainty they could not have imagined a few months ago, are still reeling in bewilderment.

Everyone acknowledges the possibility of falling into a personal abyss: losing one’s job, being betrayed by a friend or lover, being diagnosed with a potentially fatal illness, suffering the death of a child. But general chaos, civilizational death, Dionysian disruption—a deep defensive mechanism bars us from imagining this kind of disorder until we find ourselves sucked into it as if into a pit of quicksand.

Historical knowledge is no comfort in conditions of radical uncertainty–what Philip Roth in The Plot Against America called “the relentless unforeseen”: “Turned wrong way around the relentless unforeseen was what we schoolchildren studied as ‘History,’ harmless history, where everything unexpected in its own time is chronicled on the page as inevitable. The terror of the unforeseen is what the science of history hides, turning a disaster into an epic.”

“I did not choose to study history,” my late mentor Stanley Hoffmann once said to me while discussing his past as a child in wartime France. “History fell upon me.”

Covid-19 has fallen upon us, yet even so, we have a hard time believing it: “Plagues are actually a common thing,” wrote Albert Camus in The Plague, “but we find it difficult to believe in them when they fall upon our heads. … Plagues and wars always find people unprepared.”

We are sun-worshipers, who want to believe in Apollo and therefore ignore tragedy’s repeated rebirths until Dionysus’s savage inhuman cries remind us that even if the sun does rise tomorrow as always, we may not be here to witness it.

We are all existentialists now, knowing only that we must try to carry on, even if we cannot say why, for how long, or to what end.

Arthur Goldhammer is a seminar co-chair at Harvard’s Center for European Studies.