In 1837 Hans Lassen Martensen, a young theologian who would one day head the Danish church, gave a course at the University of Copenhagen on speculative dogmatics, and Hegel's philosophy became a craze among the students. The Danish Hegelians taught that faith could be taken up into philosophy and understood, with Christianity, history and logic joined in one finished system. Søren Kierkegaard, whom Martensen had tutored privately three years before, sat in the audience. He spent the rest of his life arguing that the system left out the one thing that mattered: the person who has to live, choose and believe, and who cannot do any of it by understanding. Being a Christian, on his account, was not something a Dane inherited at baptism or reached at the end of an argument. It was a task each person had to take on alone, and in his view most of his countrymen had never begun it.
He had first learned his Christianity at home. His father, Michael Pedersen Kierkegaard, a hosier from Jutland who had grown rich in Copenhagen, raised his children in a devout Lutheranism touched by the Moravian Brethren. Early death ran through the family — of the seven children, only Søren and his brother Peter Christian lived past thirty-three, the age of Christ — and Søren's journal speaks of a curse on it. When the father died in 1838 he left Søren enough money to live without holding an office. In 1840 Søren passed his theology examinations and became engaged to Regine Olsen, who was eighteen. It was the road to a parish and a marriage, and within a year he had left it. He returned her ring in August 1841, broke off the engagement for good that autumn and went to Berlin, where he heard the philosopher Schelling lecture and wrote much of Either/Or. Scholars still argue over his reasons.
The books of the next years appeared mostly under invented names: Victor Eremita, Johannes de silentio, Vigilius Haufniensis, Johannes Climacus. Each pseudonym lives inside one way of understanding a life — the aesthete who collects interesting moments, the judge who commits himself to a marriage — and the reader is left to choose between them. Kierkegaard called this indirect communication: what he cared about could not be handed over as a result, only taken up by each reader alone.
Johannes Climacus stated the claim at its sharpest in the Concluding Unscientific Postscript of 1846: truth is subjectivity. For the questions a life turns on, how a person holds a belief — with what passion, at what risk — counts as much as what is believed. Scholarship can make the truth of Christianity no more than probable, so faith is a decision, a leap, and never the conclusion of a proof. The book sold about fifty copies in his lifetime.
It appeared while the satirical weekly The Corsair was caricaturing him. In December 1845 he had exposed P. L. Møller, a critic who wrote for the paper anonymously, and dared it to attack him; for months it drew him as a frail, hunched man in trousers with uneven legs, and he became a joke in the streets he walked every day. In Two Ages, written in those weeks, he described the press as the maker of the public, a crowd that never gathers and answers for nothing, and set against it only the single individual.
His last fight, with the church itself, began over a memorial sermon. Bishop Jakob Peter Mynster, his father's pastor, died in January 1854, and Martensen, soon to succeed him as Bishop of Zealand, praised him in a sermon as a true witness to the truth. On 18 December 1854 Kierkegaard asked in the newspaper Fædrelandet whether that was so. Articles followed, then a paper of his own, The Moment, which argued that the Christianity of the New Testament no longer existed in Denmark. Nine numbers had appeared when he collapsed, and on 2 October 1855 he was taken to Frederiks Hospital. There he refused communion from a priest, since he regarded the clergy as officials of the state, and he died on 11 November, aged forty-two.
Outside Denmark he was hardly read for decades. The Danish critic Georg Brandes published a study of him in 1877, and Christoph Schrempf, a German theologian, began translating him into German in 1890. After the First World War the theologians around Karl Barth took him up, Martin Heidegger drew on him in Being and Time, and he shaped the existentialism of Karl Jaspers and Jean-Paul Sartre.