Discussed in this essay:

Philosopher of the Heart: The Restless Life of Søren Kierkegaard, by Clare Carlisle. Farrar, Straus and Giroux. 368 pages. $28.

Throughout its history, philosophy has been marked by figures who sought to demolish the prevailing intellectual systems of their moment—to practice “philosophy with a hammer,” as Friedrich Nietzsche put it—in order to look with fresh eyes at the most urgent human problems. As depicted in Plato’s early dialogues, Socrates railed against professional Sophists who charged fees to engage in what amounted to rhetorical games. By contrast, he merely wandered the agora, posing pointed questions about life’s meaning to anyone who’d listen. He insisted that he had no new knowledge to impart: his wisdom lay entirely in recognizing his own ignorance. He devoted his energy to unsettling commonly held beliefs rather than imposing his own, and he spoke of himself as an annoyance, a gadfly stinging a complacent Athenian society. To much of that society he was a laughingstock, but he also attracted a substantial following, for whom his personal example—his ironic temperament; his embrace of poverty and his detachment from worldly matters; and, especially, his equanimity in the face of death—signified at least as much as the content of his thought.

Ever since, outsider-philosophers have tended to take Socrates as their touchstone. Like Plato, they have blurred the line between philosophical and literary writing, and they have shown a talent for the kind of aphoristic insight that the general public has come to expect from philosophers. While often hostile toward religion, they have all been deeply concerned with what we might call “God questions”: Does one exist? And what should such existence or nonexistence actually mean for us here on earth? They have had ambiguous or outright adversarial relationships with the academy, and they have often been ignored in their lifetimes or treated as objects of ridicule. In defiance of a discipline that prizes disinterest and objectivity, they have openly acknowledged the connection between their ideas and their experience. A striking proportion have died young, and they are often remembered more for their attempts to authentically live out their philosophies than for the philosophies themselves. As the field has become increasingly specialized and systematized in the modern era, these figures have stood out more conspicuously, coming to represent a tradition of their own.

Our current age seems particularly desperate for whatever this tradition has to impart—the past decade has seen a glut of books about it. Such works as James Miller’s Examined Lives: From Socrates to Nietzsche, John Kaag’s Hiking with Nietzsche, Sue Prideaux’s I Am Dynamite! (Nietzsche again), Robert Zaretsky’s A Life Worth Living (Albert Camus), Karen Olsson’s The Weil Conjectures (Simone Weil), Sarah Bakewell’s At the Existentialist Café (Camus and Weil and assorted Left Bankers), and Gordon Marino’s The Existentialist’s Survival Guide (more or less the whole crew) are neither conventional biographies nor academic treatises. Instead they mine the personal histories of these thinkers for lessons on (as the title of Bakewell’s life of Montaigne has it) “How to Live.”

Søren Kierkegaard—the subject of Clare Carlisle’s Philosopher of the Heart: The Restless Life of Søren Kierkegaard—is an exemplar of the outsider-philosopher tradition, in some ways the founder of its modern strain. Nearly every one of the books listed above cites him as a precursor, and a direct line can be drawn from him to each of their subjects. Though Nietzsche never read him, Kierkegaard anticipated Nietzsche’s criticisms of rationalized Enlightenment Christianity and universal morality by half a century. A biographer reports that Weil “could not read Kierkegaard without feeling moved”; Camus owed to Kierkegaard his most influential idea, the concept of the absurd; and much of French existentialism can be understood as an effort to salvage Kierkegaard’s thought while removing the belief in God around which it was built. Ludwig Wittgenstein—another outsider whose place in the philosophical pantheon was posthumously secured—called him “by far the most profound thinker of the [nineteenth] century.”

So why has he been slow in getting the full “How to Live” treatment? Despite the great urgency and excitement of his works, and the fact that he wrote for a general audience, Kierkegaard resists popularization. His ideas are so bound up with the form of his writing that they are near-impossible to paraphrase. His use of pseudonymous stand-ins—in some books, as many as five or six serve as characters, authors, and editors—makes it hard to determine which of those ideas he even meant to claim as his own. (This is a common feature of the Socratic-ironic mode, but it is particularly striking in Kierkegaard’s case.) His writing is often formidably challenging, largely by design. Every effort in the modern age, he wrote, is geared toward making life easier; realizing that he was unequipped to contribute to this grand project, he found for himself another job: “to make difficulties everywhere.”

Yet for those willing to do the work, Kierkegaard has at least as much to tell us as any of his intellectual descendants. As Carlisle notes, part of Kierkegaard’s great appeal is that he seems to be

the first great philosopher to attend to the experience of living in a recognizably modern world of newspapers, trains, window shopping, amusement parks, and great stores of knowledge and information.

He writes about the anxiety that comes with living in that world: facing endless decisions while suspecting that none of your choices really matter, being overwhelmed by information without seeing how any of it might be put to use in your life, constantly displaying yourself to a watching world while suspecting that your innermost truth remains unknown.

Kierkegaard was born in Copenhagen in 1813. His father, Michael, had grown up in extreme poverty on the Danish Jutland, where his family worked the land of a Lutheran priest. (The name they took for themselves means “churchyard” or, by extension, “graveyard,” a fact that becomes even more suggestive when one learns that Søren is a corruption of Severinus, meaning “severe.”) A maternal uncle plucked Michael from this squalor and brought him to the capital to apprentice as a hosier. After establishing himself in this trade, he became an importer of goods from the Danish colonies, at which he proved successful enough to retire by the age of forty. He spent the remainder of his life studying theology and German philosophy, which he apparently grasped with great acuity, despite a total lack of formal education. Around the time of his retirement, his first wife died, childless. He soon married Ane Lund, a distant relation brought from the Jutland to work in the Kierkegaard home. Their first child was born five months later, and six more followed over the next decade and a half, of whom Søren Aabye was the last.

In the year of Kierkegaard’s birth, Denmark suffered a financial crash, but Michael Kierkegaard had invested his wealth in gold-backed securities, which kept their value amid rampant inflation, and he came out of the crisis one of the city’s richest men. A strict pietist with great intellectual curiosity but no aesthetic sense, he kept firm control of the household, creating a rather joyless atmosphere. Kierkegaard later spoke with admiration of his father’s religious devotion, but he also described childhood under Michael’s watch as desperately unhappy.

At his father’s insistence, Kierkegaard studied theology at the University of Copenhagen. His eldest brother, Peter Christian, had finished first in his class there, on the way to a distinguished clerical career. By comparison, Søren was an indifferent student for whom university life first of all meant freedom. He “leapt eagerly and extravagantly into the arms of his newly unveiled city,” Carlisle writes. “He dined out, drank too much coffee, smoked expensive cigars, bought new clothes, and socialized energetically.”

Copenhagen’s intellectual atmosphere was infused with the Romanticism an earlier generation of students had brought back from trips to Germany, and Kierkegaard enthusiastically embraced this spirit: “Christian doctrine, biblical exegesis and Church history interested him far less than the new kinds of literature he discovered at the university,” Carlisle tells us. He began to write, in a somewhat desultory way, contributing reactionary articles against female emancipation and freedom of the press to the local papers.

Years passed in which Kierkegaard made little progress toward his degree, while his father watched on with concern. “What I really need is to get clear about what I must do,” he wrote in his journals, “not what I must know, except insofar as knowledge must precede every act.” At the age of twenty-four, he met and fell in love with a fifteen-year-old girl named Regine Olsen, and he made frequent visits to her family’s house, courting her ambivalently while continuing to live his café life. Various literary projects failed to come to fruition, including a long essay on Hans Christian Andersen, whom Kierkegaard faulted for lacking a proper “life-view.” During this time, Carlisle writes, Kierkegaard’s

innate tendency to hyper-reflection was nourished by an intellectual culture steeped in three decades of idealist philosophy and literary irony; his experiences and feelings were wrapped in countless folds of reflection, filled with poetic significance, and suffused with existential doubts.

(In fairness, he also lost his mother, two of his sisters, and his closest brother in these years, which certainly added to his angst.)

He’d been at the university for nearly a decade and still not earned his degree when his father died in 1838, leaving him and Peter Christian as the only survivors of what had been a family of nine. Perhaps unsurprisingly, both brothers suffered from chronic depression—as had their father and as would Peter’s sons, one of whom took his own life. But in the short term, Michael’s death shook Kierkegaard out of his indolence and made him commit to the kind of life his father had wanted for him. He finished his critique of Andersen, which he published as a book, From the Papers of One Still Living. After finally passing his exams, he proposed to Regine, enrolled in the seminary, and began the dissertation that would grant him a magister degree and make him eligible to work as a pastor in the Danish church.

These developments were closely related: getting married would mean taking up a profession, having children, and serving a public role in Copenhagen society. “His life would be understood—it would be measured and judged—according to a well-established way of being in the world,” Carlisle writes, “shaped by a precise configuration of duties, customs, expectations.”

Almost as soon as he’d made this commitment, Kierkegaard recognized that it had been a mistake. He sincerely loved Regine, and he believed that marriage might bring him happiness and fulfillment, but he doubted that he was meant to be happy or fulfilled. Like many people who suffer from depression, he understood his condition to offer some essential insight on the human situation. Grappling authentically with the feeling had the appearance of a kind of vocation.

With his inheritance, he could live independently for a decade or two, until the early death to which he believed himself fated. He could dedicate himself to working through the meaning of his anxiety and despair. Such a thing would of course be impossible for a married man living a respectable bourgeois life. In a Protestant society with no monastic tradition or celibate clergy, marriage was man’s highest calling, and Kierkegaard took that calling very seriously. He was not trying to escape the rigors of marriage for a return to the shallow pleasures of bachelorhood. He was, instead, called to something even more rigorous. Once he had completed his degree and published his dissertation, On the Concept of Irony with Continual Reference to Socrates—in other words, done everything necessary to embark on married life—he proceeded to break the engagement.

Sacrificing his own happiness to a stringent vision was one thing; sacrificing Regine’s was another. So Kierkegaard—who could be too psychologically subtle for anyone’s good—contrived to make Regine believe that he was a cad who had trifled with her heart, rather than a faithful lover facing an even higher task than marriage. In this case, she could in good conscience claim to be ending the relationship herself, which, he thought, would be better for her both socially and psychologically. In the event, Regine did not cooperate: she refused to take responsibility for the break, begged him not to leave, threatened to kill herself if he did, and acted in every way like a woman wronged, which is exactly what she was.

In the wake of the public scandal that followed, Kierkegaard escaped to Berlin for five months. There he attended Schelling’s lectures on Hegel, which he described in a letter as “endless nonsense both in an extensive and an intensive sense,” though he took copious notes on them. Hegel had died a decade earlier, but his ideas remained a dominant force in European intellectual life, and Kierkegaard had a fiercely negative reaction to them.

Hegelianism—at least as Kierkegaard understood it from Schelling and from the Danish intellectuals who had brought it to Copenhagen—treated history as an intelligible process by which humanity progressed toward a state of spiritual freedom. This process unfolded dialectically, as the inherent contradictions of one state gave rise to an opposing reaction into which it was absorbed. Modern man, arriving rather late in the day, was in a position to recognize this process, to look on it as from a summit, and in this way history became conscious of itself as history.

To Kierkegaard, this sweeping teleological view left no room for human agency. That is, we might be free to make choices, but these choices could not possibly matter in the grand scheme. If all things were resolved into their opposites—if the world was a series of “both/and” relationships—choosing the one always meant choosing the other. Yet his experience with Regine had taught Kierkegaard that some choices—precisely the ones that matter most to a person—really do exclude their alternatives. What’s more, while Hegelianism encouraged us to view humanity from a great height, we could not help being involved in our own lives. Whatever truth the long view might reveal to mankind could not help us there.

While in Berlin, Kierkegaard began a work that would demonstrate, in Carlisle’s words, “that the distinctive dialectical logic that shaped Hegel’s thinking, and reproduced itself at every level of his encyclopedic philosophy, becomes ridiculous when adopted as a life-view.” Either/Or was his third published book, but it was the true initiation of what Kierkegaard called “my authorship.” It is a long, strange work, built out of seemingly disparate elements. A preface signed by the pseudonymous “editor,” Victor Eremita (“the victorious hermit”), explains that what follows are documents found in a desk he has bought at a secondhand store. A first set of papers belonged to a writer known only as “A,” a brilliant but directionless young man, rather like Kierkegaard before his proposal to Regine. A’s papers include a collection of aphorisms and a series of essays on subjects such as Mozart’s treatment of the Don Juan theme and tragedy in modern drama. Taken together, these papers give a picture of a life approached aesthetically, one in which a person might make any number of choices—whom to love that night, what show to see—none of which would change anything. (“Hang yourself and you will regret it. Do not hang yourself and you will also regret it.”)

This section of the book culminates with the “Seducer’s Diary,” which is among A’s papers but is ascribed to yet another author, Johannes, who has “attempted to accomplish the task of living poetically.” Johannes describes in excruciating detail his seduction of a young woman. He feels a genuine love for her, a love he appreciates as he might a beautiful poem or a piece of music. He entices her into loving him in return, and they eventually consummate this love. “But now it is finished,” he writes brutally in the last entry, “and I never want to see her again.”

The second set of papers consists of letters written to A by a Judge William, who has embarked, as Kierkegaard could not, on the project of marriage, and who urges A to do the same. While A represents the aesthetic approach to life, the judge argues for the ethical approach, in which our decisions commit us to something, have real consequences, and so are real choices. There is a certain smugness to the man, who is happy in his marriage and his comfortably respectable public life, but there is no doubt that Kierkegaard finds this the more admirable option of the two. Only at the very end of the book do we begin to see the possibility of a third approach, suggested in a sermon that William sends to A, written by a fifth author, on the theme: against God, we are all in the wrong.

Either/Or created a great stir in Copenhagen upon publication, and it would remain throughout Kierkegaard’s life his only commercially successful book. Published in two long volumes, it was widely misunderstood; many people never got to the second part and took the first as a pure expression of the aesthetic worldview rather than a critique of it. Readers were particularly scandalized by the “Seducer’s Diary,” and tended to treat Johannes as a stand-in for the author (whom many suspected to be Kierkegaard). In fact, Kierkegaard seems to have intended for Regine, at least, to take the book this way, so that it would help her get over him. Once again his stratagem failed: at the height of Kierkegaard’s notoriety, Regine nodded to him at an Easter church service, suggesting that she knew the truth in his heart; he responded by fleeing again to Berlin.

On this second trip, Kierkegaard wrote what is probably his most widely read book today. Although it is the only one of the early pseudonymous works that does not directly take up the theme of the broken engagement, Fear and Trembling is in many ways Kierkegaard’s most sustained reckoning with his treatment of Regine. By Kierkegaard’s own accounting, his behavior had been wrong; he should have fulfilled his commitment to her. Yet he was certain that he had done the right thing. How did one make sense of this paradox? Kierkegaard still believed that marriage was the highest ethical calling, and he had failed to heed this call. But despite his public show to the contrary, he had not abandoned Regine for the shallow, undirected pleasures of the aesthetic life. Rather, he had committed himself to something higher. What was this higher thing? Did it even make sense to speak of a calling higher than the ethical life? A tentative answer to this question was offered by the sermon at the end of Either/Or; now he took it up again, and took it further, with the story of the binding of Isaac.

God’s covenant with his people begins with a promise to the old and childless Abraham that his descendants will be as many as the stars in the sky. This promise is advanced with the birth of a son, Isaac, but God commands Abraham to sacrifice Isaac atop Mount Moriah. From the historical point of view, we know that this is a test of faith: Abraham will bring Isaac up the mountain and bind him for the sacrifice, but God will intervene before it is completed. Yet it is in the nature of such a test that one can’t know it to be a test at the time. Abraham must show himself willing to do something inexcusable, and the fact that he never actually does it is beside the point. What’s more, he does not tell anyone—not even Isaac—what he is doing. He suffers the anxiety of that trip up Mount Moriah alone, suffers even the possibility that he has misunderstood God’s command, that he is about to do something unforgivable. Finally, having passed the test, he descends the mountain again and returns to his old life, proceeding as though nothing had happened—as indeed, objectively, nothing did.

For Kierkegaard, this was the nature of the truly religious life. It entailed an inward turning toward God, one that could not be reduced to a moral law. In the preceding decades, great effort had been made to rationalize Christianity and situate it as the foundation of a universally binding ethical code. The problem, from Kierkegaard’s perspective, was that Jesus did not call us to obey a set of rules; he called us to love. It cannot be that adherence to an ethical code is the highest life, because it is possible to obey every rule placed in front of you without ever feeling love in your heart. To the aesthetic and the ethical was added a third category, the religious, which was beyond both.

Placed in this tripart relationship, the aesthetic, the ethical, and the religious seem almost to represent a Hegelian progression, but one stage does not lead inevitably to the next as they do in Hegel’s system. There is no internal contradiction in the aesthetic life that ushers us out of it. We must choose to be ethical as an act of individual will. And since choosing in this way, and standing by our choices, is precisely what the ethical entails, we must in a sense already be living in the ethical sphere in order to choose it. Nothing in the aesthetic sphere—which is precisely the sphere wherein such choices cannot occur—could make us ethical by degrees. (From A’s papers: “Experience shows that it is not at all difficult for philosophy to begin. . . . But it is always difficult for philosophy and philosophers to stop.”) What is required is a qualitative leap from one state to another.

A similar leap must move us from the ethical to the religious. The ethical sphere gives us the satisfaction of adherence to a code, seen in Judge William’s smug complacency, and so it does not push us on to something greater. Yet we continue to have moments of anxiety or despair, as when we sense that no amount of upstanding behavior will change the fact that we and all we love are fated to die, or when we recognize that our ethical code is built on air, that it does not—cannot—have a universal basis, that the Christian story on which these ethics claim to be built cannot be rationalized as a Hegelian synthesis of the absolute and the particular or the necessary and the contingent, but must be accepted as a paradox, an absurdity.

In Kierkegaard’s view, it is precisely this anxiety that makes our inward turning possible. It is in this anxiety that we begin to be truly religious. For religious life does not unfold according to a universal code. Like Abraham, we cannot know in advance if we are doing it correctly. We must give ourselves over to it, as Paul says in his first letter to the Corinthians, in great fear and trembling. This is the famous leap of faith for which Kierkegaard is perhaps best known (although he never used the expression). The phrase is sometimes taken to mean that we ought to throw ourselves into belief even though we have no intellectual basis for doing so. In fact, it means that no amount of philosophical consideration or ethical behavior can bring about the inward turning that religious life requires.

Another fact about this inward turning is that we falsify it when we attempt to put it on display in the way that we might our ethical behavior. Of course, writing about the religious was a form of precisely this kind of objectified display. Kierkegaard was aware of the contradiction, and he had an ambivalent relationship to his own work. (He does not seem to have had any relationships that weren’t ambivalent.) This accounts in part for his use of pseudonyms, which was not just a writerly device. For some years, he took great care to keep his literary identity concealed. He made a point amid his work to go on long walks so that he could be seen by the people of Copenhagen, who knew his distinctive figure, and he turned up at the theater during intermissions, giving the impression that he’d spent his evening at the show, before sneaking home to work. He went out of his way to appear still mired in the aesthetic stage.

A few months after the appearance of Either/Or, Kierkegaard had published under his own name a collection of “upbuilding discourses”—essentially, Christian sermons, though he didn’t put it this way, because he didn’t have the authority of the pulpit. Throughout the next decade he would publish prolifically, sometimes multiple titles on the same day or within weeks of one another, and he frequently released a pseudonymous work and a signed collection of discourses in quick succession. This seems to have been in part to throw people off his scent.

When he finally acknowledged his authorship of the pseudonymous works, he stated simultaneously that in them

there is not a single word by me. I have no opinion about them except as a third party, no knowledge of their meaning except as a reader, not the remotest private relation to them, since it is impossible to have that to a doubly reflected communication.

He declared his authorship over, though after a few years he took it up again.

His books sold in very small numbers, and the cost of copyediting, typesetting, and printing was greater than the income on his inheritance, so he quickly spent down the principal. This did not trouble Kierkegaard, who remained confident that he was destined to die young. He was forced to sell his family’s house and live as a renter. Still he published at a prolific rate, and he wrote even more in his journals, which he prepared for posterity. At the same time, he insisted that his Christian discourses, along with his increasingly strident attacks on the official Danish church, contained his “real” work, while the pseudonymous texts were a kind of aesthetic curiosity. This remained the consensus on Kierkegaard’s legacy into the twentieth century.

In the fall of 1855, fifteen years after commencing his authorship, Kierkegaard collapsed in the street. A few weeks later he died at age forty-two. He had thought he might last a decade or two after his father’s death; he’d made it seventeen years. A note in his desk explained that all remaining assets should go to a Mrs. Regine Schlegel; if she refused to accept, she should be asked to administer them for the poor. As it happened, everything he had left went to pay for his burial.

Philosopher of the Heart begins with Kierkegaard’s second trip to Berlin. At first glance, this seems a strange choice, since the initial break with Regine and the earlier trip are so clearly the turning point in Kierkegaard’s career. But Carlisle has set out to write “a Kierkegaardian biography of Kierkegaard,” which means that she cannot take the typical approach of standing complacently outside the events of his life, recounting them chronologically, with the historian’s retrospective knowledge of what they all mean and where they will lead. One of Kierkegaard’s most famous insights was that life—which the philosophers teach us can only be understood backward—must nonetheless be lived forward. Carlisle attempts to pay justice to this idea by picking up Kierkegaard’s story at various moments of uncertainty, placing us in those moments with him, and using them as vantage points from which to survey the past.

It’s a theoretically sound approach, but the result is sometimes awkward. While Kierkegaard’s work was intimately bound to his experience, so many of his life’s most important events were interior. (Indeed, he thought this was true of all lives.) This means that some chapters are structured around the “event” of a long train ride or an hour spent staring out a window. It’s difficult to see what this biographical framing adds to the understanding of the work. While Carlisle emphasizes the importance of movement in Kierkegaard’s thought, her book can sometimes be curiously static.

It is at its best when providing more straightforward explication. Carlisle is a professor of philosophy and theology, and the author of a more conventional (and exceptionally good) study of the early pseudonymous books. She has an absolute mastery of Kierkegaard’s life and works. At the same time, she is a lucid and stylish writer who shares some of her subject’s suspicions of the academic approach. She succeeds wonderfully at what is obviously her chief goal, which is to give us some sense of why Kierkegaard’s task mattered so urgently for him, and of why it might matter for us. Carlisle would likely agree that when it comes to understanding Kierkegaard’s thought—and thinking through what it might mean to put that thought into practice—there can be no substitute for reading his work in all its strange difficulty. I hope she will take it as a compliment when I say that Philosopher of the Heart’s greatest virtue is that it is likely to inspire some readers to do just that.

So what does Kierkegaard have to tell our age?

It is almost a truism now that we are each called to take up our own life as a creative project, to make of it what we will, but our culture treats this project as a kind of performance, to be judged by others according to appearances. Kierkegaard’s concept of inwardness gives us this task in a very different form. No amount of likes or clicks can tell us whether we are living the life to which we have actually been called. In fact, the process of submitting our lives for public approval can only ever undermine our efforts. So much about contemporary society—not just the public curation of social media, but the consumer culture that presents us an endless stream of choices, none of which ultimately matter—is designed to distract from the truth of our existential situation. Kierkegaard tells us to hold this truth always in mind, to move toward, not away from, the anxiety and despair that must naturally follow from recognizing it.

But perhaps the greatest thing Kierkegaard has to tell our age is that we might stop thinking of ourselves as occupying an age at all—stop thinking that the meaning of our lives is determined by impersonal historical forces outside our control, or that our primary objective in life is to respond to the peculiar challenges of our moment. In 1848, the liberal revolutions sweeping through Europe arrived in Denmark, transforming the absolute monarchy into a constitutional democracy. “Out there everything is agitated,” Kierkegaard wrote in his journals. “I sit in a quiet room (no doubt I will soon be in bad repute for indifference to the nation’s cause)—I know only one risk, the risk of religiousness.”

This is the risk he believed we all must take up on our own terms. Since no one else can take it up for us, it doesn’t matter how late in history we have arrived at it. We are called to the same fundamental task as every previous age, and that is to learn how to love: “Whatever one generation learns from another,” Kierkegaard wrote, “no generation learns the genuinely human from a previous one.”

We are all Hegelians now, sure that the problems we face are not just unprecedented but systemic, too large for any individual to address. A sense of great urgency combines with a sense of acute hopelessness. We feel at once that the world desperately needs changing and that we are unequipped to change it. Kierkegaard tells us to begin by changing our own hearts.