In my sixth form at school we had weekly discussions about topics that were meant to sharpen our minds for life, and help to get us into a university: “The bomb: a justifiable evil?”; “Explain RG Collingwood’s philosophy of history” (our teacher liked Collingwood’s work); “The pursuit of happiness”. This last provoked the only conversation I can remember joining with any real confidence. My mother had recently suffered a serious accident and was dangerously ill in hospital; I had decided that life was an affair of random violence, and there wasn’t much point in chasing happiness. Besides, I’d started to write poems, and had already voted myself everlasting membership of what I later heard Hugo Williams call “the sadness club”. It seemed the only organisation in the world worth joining.

Not that I was continuously miserable, but I was already convinced that happiness is much more likely to be something we find in the margins of whatever else we might be pursuing (love, adventure, money or reputation). It was – it is – an incidental thing, rather than a safe and secure destination.

And yet we still want it (so in that sense we pursue it), because we even more definitely don’t want its opposite: unhappiness. Which means that all of us stay more or less alert to the possibility of finding it. Yet as we look around for it (or rather, as we retune our watchfulness), we immediately have to admit that part of the difficulty we face in tracking it down is knowing how elusive any definition of happiness must prove. Because the existence of happiness depends, in some important respect, on our being beside ourselves, on our setting aside our self-consciousness, perhaps even our rational and intellectual engagement with life, and surrendering instead to some other governing principle: our instincts, perhaps, or our senses. The sort of rapture, at any rate, that Seamus Heaney catches at the end of his poem Postscript, where he feels

neither here nor there,

A hurry through which known and strange things pass

As big soft buffetings come at the car sideways

And catch the heart off guard and blow it open.”

Then there are other problems, still right near the beginning of things. The necessary self-surrender means that our evocations of happiness are likely to be retrospective (because in the moment of enjoyment, we’re not equipped to comment), which in turns means we have to ask: does this mean that they’re all, in a sense, unreliable? Maybe, to the extent that they all grant structure and expression to something that contains elements that are not compatible with shaping and saying. This is partly what Philip Larkin meant to suggest, when he quoted the French novelist Henry de Montherlant to the effect that “happiness writes white”. He meant that happiness cannot be captured and articulated: the blissfulness of bliss depends on it being wordless.

But de Montherlant’s excellent phrase can be read in other ways as well. One of them is not so much to do with notions of what can and cannot be said, as with what can and cannot be seen. White writing is only invisible on a white background; against any colour darker than itself it’s plain for all to read. Bearing this in mind, we could argue that even the most melancholy and despairing pieces of writing have whiteness in them: between the lines, for instance; between the individual letters; across about half of the page, in fact, and maybe creating a kind of counterweight to whatever is being said in the words themselves.

To put all this another way, happiness might be present in a piece of writing even when it isn’t spelled out or made manifest by some other means. We might say, for instance, that the very fact of a poem’s existence (or a novel’s, or whatever) represents a form of happiness because it is a little miracle of something-from-nothing, an affirmation of humanity. Think of Thomas Hardy’s second wife Florence meeting a visitor at the door of Max Gate and telling him that he couldn’t disturb her husband just yet, because Tom was in his study writing one of his miserable little poems and grinning all over his face. Hardy may have been smiling because he enjoyed impaling his characters on the thorns of life. But even if he was, it doesn’t rule out the possibility that like everyone else who has ever written anything, he felt that he was striking a blow against nothingness.

To put it another way again, true happiness (as opposed to mere escapism) can only exist within hailing distance of its opposite. Furthermore, its quality is likely to improve when the balance between opposite states of mind is most finely poised, when the fundamental paradoxes of existence are most tightly bound to one another. In writing, this would mean clinging tight to Samuel Beckett’s words from Worstward Ho:

Ever tried. Ever failed. No matter. Try again. Fail again. Fail better.”

In philosophical terms, it would mean remembering John Keats’s lines in the Ode to Melancholy:

Ay, in the very temple of Delight

Veil’d Melancholy has her sovran shrine,

Though seen of none save him whose strenuous tongue

Can burst Joy’s grape against his palate fine”

The point being that even the most self-confident creator knows (or should know) that their best efforts are going to fall short of the ideal they imagine, in just the same way that everyone who has ever enjoyed themselves knows their pleasure has a multitude of strings attached, and might even have to admit the possibility of distaste.

Which quite properly implies: as in art, so in life. Like most people, I know that my own best chance of happiness is likely to occur in the particular areas of activity I already know that I enjoy most. (That sounds obvious, but it can take a while to find out what these areas might be.)

But even here, the critical and defining element is paradox. I can be happy when I’m at work teaching, for instance, though I also sometimes find it frustrating. I can be happy walking through a landscape, or even simply looking at a landscape, though these days I am also and simultaneously very bothered by its fragility. I can be happy when I’m reading, or looking at pictures, or listening to music, yet often the thoughts and sensations that occur to me while I do these things are to do with the sadness of the creatures. I can be happy sharing the happiness of others, but I know it won’t last for long.

I’m not saying anything here about my happiness at home – only because home is private. But happiness is there all right, believe me, more than anywhere else and less acquainted with its opposite.

So does all this mean that nothing much has changed in my apprehension of happiness since that sixth-form classroom? On the face of it, yes: I still think I’d be on a hiding to nothing if I set off in pursuit of happiness as an end in itself, and I even more deeply feel that such happiness as I do experience is brought into being by my familiarity with its opposite. Especially now that I’m the age I am, and can see “the only end of age” more clearly than ever. It means that the beauty of every spring, the beauty of everything, is fanned into happiness by a sharper and sharper sense that I will see it only a few times more.

And yet at the same time, or rather, over the same time as these convictions have hardened in me, I have also learned something else that seems to pull in a slightly different direction. Which is that while I accept unhappiness as an inevitable part of the human condition, and appreciate its role in stimulating happiness itself, I also found myself having to fight harder and harder to hold the balance between the two: to keep the paradox a paradox, to maintain the poise. Because life is always trying to tip it in the direction of unhappiness, and too much of that … well, I don’t need to finish the sentence. Better to remember what Alexander Pushkin said about these things, and to ponder what more he implied: “They say that misfortune is a good school. Yes, true. But happiness is the best university.”

Andrew Motion’s second Treasure Island sequel, The New World, is published by Jonathan Cape