I fell for Søren Kierkegaard as a teenager, and he has accompanied me on my intellectual travels ever since, not so much side by side as always a few steps ahead or lurking out of sight just behind me. Perhaps that’s because he does not mix well with the other companions I’ve kept. I studied in the Anglo-American analytic tradition of philosophy, where the literary flourishes and wilful paradoxes of continental existentialists are viewed with anything from suspicion to outright disdain. In Paris, Roland Barthes might have proclaimed the death of the author, but in London the philosopher had been lifeless for years, as anonymous as possible so that the arguments could speak for themselves.

Discovering that your childhood idols are now virtually ancient is usually a disturbing reminder of your own mortality. But for me, realising that 5th May 2013 marks the 200th anniversary of Søren Kierkegaard’s birth was more of a reminder of his immortality. It’s a strange word to use for a thinker who lived with a presentiment of his own death and didn’t reach his 43rd birthday. Kierkegaard was the master of irony and paradox before both became debased by careless overuse. He was an existentialist a century before Jean-Paul Sarte, more rigorously post-modern than postmodernism, and a theist whose attacks on religion bit far deeper than many of those of today’s new atheists. Kierkegaard is not so much a thinker for our time but a timeless thinker, whose work is pertinent for all ages yet destined to be fully attuned to none.

It’s easy enough to see why I fell in love with Kierkegaard. Before years of academic training does its work of desiccation, young men and women are drawn to philosophy and the humanities by the excitement of ideas and new horizons of understanding. This youthful zeal, however, is often slapped down by mature sobriety. I remember dipping into the tiny philosophy section of my school library, for example, and finding Stephan Körner’s 1955 Pelican introduction to Kant. I couldn’t make head nor tail of it. Strangely, this did not put me off philosophy, the idea of which remained more alluring than the little bit of reality I had encountered.

Kierkegaard was not so much an oasis in this desert as a dramatic, torrential thunderstorm at the heart of it. Discovering him as a 17-year-old suddenly made philosophy and religion human and exciting, not arid and abstract. In part that’s because he was a complex personality with a tumultuous biography. Even his name emanates romantic darkness. ‘Søren’ is the Danish version of the Latin severus, meaning ‘severe’, ‘serious’ or ‘strict’, while ‘Kierkegaard’ means churchyard, with its traditional associations of the graveyard.

He knew intense love, and was engaged to Regine Olsen, whom he describes in his journals as ‘sovereign queen of my heart’. Yet in 1841, after four years of courtship, he called the engagement off, apparently because he did not believe he could give the marriage the commitment it deserved. He took love, God and philosophy so seriously that he did not see how he could allow himself all three.

He was a romantic iconoclast, who lived fast and died young, but on a rollercoaster of words and ideas rather than sex and booze. During the 1840s, books poured from his pen. In 1843 alone, he published three masterpieces, Either/Or, Fear and Trembling, and Repetition.

Kierkegaard achieved the necessary condition of any great romantic intellectual figure, which is rejection by his own time and society

All of this, however, was under the shadow of a deep melancholy. Five of his seven siblings died, three in the space of the same two years that claimed his mother. These tragedies fuelled the bleak religiosity of his father, who believed he had been punished for cursing God on a Jutland heath for His apparent indifference to the hard, wretched life of the young sheep farmer. When his father told Søren about this, it seems that the son adopted the curse, along with his father’s youthful sins.

Yet alongside this melancholy was a mischievous, satirical wit. Kierkegaard was a scathing critic of the Denmark of his time, and he paid the price when in 1846 The Corsair, a satirical paper, launched a series of character attacks on him, ridiculing his gait (he had a badly curved spine) and his rasping voice. Kierkegaard achieved the necessary condition of any great romantic intellectual figure, which is rejection by his own time and society. His biographer, Walter Lowrie, goes so far as to suggest that he was single-handedly responsible for the decline of Søren as a popular first name. Such was the ridicule cast upon him that Danish parents would tell their children ‘don’t be a Søren’. Today, Sorensen — son of Søren — is still the eighth most common surname in Denmark, while as a first name Søren itself doesn’t even make the top 50. It is as though Britain were full of Johnsons but no Johns.

All this was more than enough to draw my open but largely empty 17-year-old mind to him. In the battle for intellectual affections, how could the likes of A J Ayer’s Language, Truth and Logic (1936) or Willard Van Orman Quine’s Word and Object (1960) compete with Kierkegaard’s The Sickness Unto Death (1849) or Stages on Life’s Way (1845)? What is more interesting, however, is why the intellectual affair lasted even as I became a (hopefully) less impressionable, older atheist.

If Kierkegaard is your benchmark, then you judge any philosophy not just on the basis of how cogent its arguments are, but on whether it speaks to the fundamental needs of human beings trying to make sense of the world. Philosophy prides itself on challenging all assumptions but, oddly enough, in the 20th century it forgot to question why it asked the questions it did. Problems were simply inherited from previous generations and treated as puzzles to be solved. Kierkegaard is inoculation against such empty scholasticism. As he put it in his journal in 1835:

What would be the use of discovering so-called objective truth, of working through all the systems of philosophy and of being able, if required, to review them all and show up the inconsistencies within each system … what good would it do me if truth stood before me, cold and naked, not caring whether I recognised her or not, and producing in me a shudder of fear rather than a trusting devotion?

When, for example, I became fascinated by the philosophical problem of personal identity, I also became dismayed by the unwillingness or inability of many writers on the subject to address the question of just why the problem should concern us at all. Rather than being an existential problem, it often became simply a logical or metaphysical one, a technical exercise in specifying the necessary and sufficient conditions for identifying one person as the same object at two different points in time.

So even as I worked on a PhD on the subject, located within the Anglo-American analytic tradition, I sneaked Kierkegaard in through the back door. For me, Kierkegaard defined the problem more clearly than anyone else. Human beings are caught, he said, between two modes or ‘spheres’ of existence. The ‘aesthetic’ is the world of immediacy, of here and now. The ‘ethical’ is the transcendent, eternal world. We can’t live in both, but neither fulfils all our needs since ‘the self is composed of infinitude and finitude’, a perhaps hyperbolic way of saying that we exist across time, in the past and future, but we are also inescapably trapped in the present moment.

The limitations of the ‘ethical’ are perhaps most obvious to the modern mind. The life of eternity is just an illusion, for we are all-too mortal, flesh-and-blood creatures. To believe we belong there is to live in denial of our animality. So the world has increasingly embraced the ‘aesthetic’. But this fails to satisfy us, too. If the moment is all we have, then all we can do is pursue pleasurable moments, ones that dissolve as swiftly as they appear, leaving us always running on empty, grasping at fleeting experiences that pass. The materialistic world offers innumerable opportunities for instant gratification without enduring satisfaction and so life becomes a series of diversions. No wonder there is still so much vague spiritual yearning in the West: people long for the ethical but cannot see beyond the aesthetic.

In evocative aphorisms, Kierkegaard captured this sense of being lost, whichever world we choose: ‘Infinitude’s despair is to lack finitude, finitude’s despair is to lack infinitude.’ Kierkegaard thus defined what I take to be the central puzzle of human existence: how to live in such a way that does justice both to our aesthetic and our ethical natures.

Kierkegaard showed that taking religion seriously is compatible with being against religion in almost all its actual forms

His solution to this paradox was to embrace it — too eagerly in my view. He thought that the figure of Christ — a man-made God, wholly finite and wholly infinite at the same time — was the only way to make sense of the human condition, not because it explains away life’s central paradox but because it embodies it. To become a Christian requires a ‘leap of faith’ without the safety net of reason or evidence.

Kierkegaard’s greatest illustration of this is his retelling of the story of Abraham and Isaac in Fear and Trembling (1843). Abraham is often held up as a paradigm of faith because he trusted God so much he was prepared to sacrifice his only son on his command. Kierkegaard makes us realise that Abraham acted on faith not because he obeyed a difficult order but because lifting the knife over his son defied all morality and reason. No reasonable man would have done what Abraham did. If this was a test, then surely the way to pass was to show God that you would not commit murder on command, even if that risked inviting divine wrath. If you heard God’s voice commanding you to kill, surely it would be more rational to conclude you were insane or tricked by demons than it would to follow the order. So when Abraham took his leap of faith, he took leave of reason and morality.

How insipid the modern version of faith appears in comparison. Religious apologists today might mumble about the power of faith and the limits of reason, yet they are the first to protest when it is suggested that faith and reason might be in tension. Far from seeing religious faith as a special, bold kind of trust, religious apologists are now more likely to see atheism as requiring as much faith as religion. Kierkegaard saw clearly that that faith is not a kind of epistemic Polyfilla that closes the small cracks left by reason, but a mad leap across a chasm devoid of all reason.

That is not because Kierkegaard was guilty of an anarchic irrationalism or relativistic subjectivism. It is only because he was so rigorous with his application of reason that he was able to push it to its limits. He went beyond reason only when reason could go no further, leaving logic behind only when logic refused to go on.

In a pluralist world, there is no hope of understanding people who live according to different values if we only judge them from the outside

This was powerful stuff for a teenager such as me who was losing his religious belief. What Kierkegaard showed was that the only serious alternative to atheism or agnosticism was not what generally passes for religion but a much deeper commitment that left ordinary standards of proof and evidence completely behind. Perhaps that’s why so many of Kierkegaard’s present-day admirers are atheists. He was a Christian who nonetheless despised ‘Christendom’. To be a Christian was to stake one’s life on the absurdity of the risen Christ, to commit to an ethical standard no human can reach. This is a constant and in some ways hopeless effort at perpetually becoming what you can never fully be. Nothing could be more different from the conventional view of what being a Christian means: being born and baptised into a religion, dutifully going to Church and partaking in the sacraments. Institutionalised Christianity is an oxymoron, given that the Jesus of the Gospels spent so much time criticising the clerics of his day and never established any alternative structures. Kierkegaard showed that taking religion seriously is compatible with being against religion in almost all its actual forms, something that present-day atheists and believers should note.

Kierkegaard would undoubtedly have been both amused and appalled at what passes for debate about religion today. He would see how both sides move in herds, adhering to a collectively formed opinion, unwilling to depart from the local consensus. Too many Christians defend what happens to pass for Christianity in the culture at the time, when they should be far more sceptical that their churches really represent the teachings of their founder. Too many atheists are just as guilty of rallying around totems such as Charles Darwin and the scientific method, as though these were the pillars of the secular outlook rather than merely the current foci of its attention.

Kierkegaard’s views on religion are not the only way in which his critique of ‘the present age’ is strangely timely for us, and likely to be the same for future readers. ‘Our age is essentially one of understanding and reflection, without passion, momentarily bursting into enthusiasm,’ he wrote in 1846, ‘and shrewdly lapsing into repose.’ Passion in this sense is about bringing one’s whole self to what one does, including reasoning. What is much more common today is either a sentimental subjectivity, in which everything becomes about your own feelings or personal story; or a detached objectivity in which the motivations and interests of the researchers are deemed irrelevant. Kierkegaard insisted on going beyond this objective/subjective choice, recognising that honest intellectual work requires a sincere attempt to see things as they are and an authentic recognition of how one’s own nature, beliefs and biases inevitably shape one’s perceptions.

This central insight is nowhere more developed than in his pseudonymous works. Many of Kierkegaard’s most important books do not bear his name. Concluding Unscientific Postcript (1846) is written by Johannes Climacus; Fear and Trembling (1843) by Johannes de Silentio; Repetition (1843) by Constantin Constantius; while Either/Or (1843) is edited by Victor Eremita. This is not just some ludic, post-modern jape. What Kierkegaard understood clearly was that there is no neutral ‘objective’ point of view from which alternative ways of living and understanding the world can be judged. Rather, you need to get inside a philosophy to really see its attractions and limitations. So, for example, to see why the everyday ‘aesthetic’ life is not enough to satisfy us, you need to see how unsatisfying it is for those who live it. That’s why Kierkegaard writes from the point of view of people who live for the moment to show how empty that leaves them. Likewise, if you want to understand the impossibility of living on the eternal plane in finite human life, see the world from the point of view of someone trying to live the ethical life.

This approach makes many of Kierkegaard’s books genuine pleasures to read, as literary as they are philosophical. More importantly, the pseudonymous method enables Kierkegaard to achieve a remarkable synthesis of objectivity and subjectivity. We see how things are from a subjective point of view, and because they really are that way, a form of objectivity is achieved. This is a lesson that our present age needs to learn again. The most complete, objective point of view is not one that is abstracted from the subjective: it is one that incorporates as many subjective points of view as are relevant and needed.

This also provides the link between imagination and rationality. A detached reason that cannot enter into the viewpoints of others cannot be fully objective because it cannot access whole areas of the real world of human experience. Kierkegaard taught me the importance of attending to the internal logic of positions, not just how they stand up to outside scrutiny.

This is arguably even more vital today than it was in Kierkegaard’s time. In a pluralist world, there is no hope of understanding people who live according to different values if we only judge them from the outside, from what we imagine to be an objective point of view but is really one infused with our own subjectivity. Atheists need to know what it really means to be religious, not simply to run through arguments against the existence of God that are not the bedrock of belief anyway. No one can hope to understand emerging nations such as China, India or Brazil unless they try to see how the world looks from inside those countries.

But perhaps Kierkegaard’s most provocative message is that both work on the self and on understanding the world requires your whole being and cannot be just a compartmentalised, academic pursuit. His life and work both have a deep ethical seriousness, as well as plenty of playful, ironic elements. This has been lost today, where it seems we are afraid of taking ourselves too seriously. For Kierkegaard, irony was the means by which we could engage in serious self-examination without hubris or arrogance: ‘what doubt is to science, irony is to personal life’. Today, irony is a way of avoiding serious self-examination by believing one is above such things, a form of superiority masquerading as modesty. It might be spotty, angst-filled adolescents who are most attracted to the young Kierkegaard, but it’s us, the supposed adults, who need the 200-year-old version more than ever.