I’m not entirely sure that this is the picture I am writing about. Three or four years ago… And here we have another problem. It feels like three or four years ago, but time passes at such a rate that, in recent years, there have been quite a few instances when I’d thought something had taken place a couple of years ago only to discover that it actually occurred in the previous century. So it’s possible that by ‘three or four years’ I mean eight or nine.

Anyway, at some point in the last decade I was killing time – however quickly it passes, there are always odd pockets that need somehow to be disposed of – at Tate Britain, cruising the Turners. His output was so huge that you are always coming across pictures you’ve never seen before. On this occasion the painting that took my eye showed – as I remember it – figures in some kind of room or cellar, confronted by a source of intense and radiant light.

Although I can’t remember when it happened or exactly what the painting looked like, I remember, very clearly, the jolt of seeing it for the first time. I took some notes that I’ve been unable to locate and which I never got round to writing up properly. I probably intended using the painting in a piece of fiction, contriving a situation in which someone encountered it in a gallery or in reproduction, or found themselves in a real-life equivalent of the scene depicted.

What kind of scene might this have been? In the late 1990s I spent quite a few nights at underground parties in venues whose settings – the cavernous railway arches near London Bridge, for example – closely resembled the architecture in the painting. Typically, there’d be a warren of rooms, the exact layout of which could never quite be committed to memory.You wandered from room to room, each promising – courtesy of the light and sound emanating from it – something alluring and magical. Often the lights made the other party-goers seem non-corporeal, spectral. Outside every set of arches you stood on the threshold of beckoning revelation. A revelation akin to the one that Turner’s painting simultaneously promises – and refuses – to reveal.

Since we are talking here about memory, I wonder if these words – room, threshold, revelation – immediately suggest to you another cultural artefact… Yes, exactly, Andrei Tarkovsky’s Stalker. Having guided the Professor and the Writer through the Zone, the Stalker brings them to the threshold of the Room where their deepest wishes will come true. On the brink of being granted this defining illumination they falter and turn back. In place of revelation there is uncertainty, doubt.

It has often been observed that the desolate beauty of Tarkovsky’s Zone imaginatively prefigures the 30-kilometre exclusion zone surrounding Chernobyl, at the heart of which the damaged reactor was sealed in the so-called sarcophagus. (Many of Robert Polidori’s Chernobyl photographs in his 2003 book, Zones of Exclusion, could double as stills from the set of Tarkovsky’s film.) The source of recessed light in Turner’s painting does not look natural – especially since everything about the interior suggests that it is a cellar, some kind of subterranean dungeon. It is an emanation of pure energy. It is the annihilating light that the artist, according to D.H. Lawrence, ‘always sought’: a light that would ‘transfuse the body, till the body was carried away, a mere bloodstain’. It is the light of definitive or clinching revelation, which, for Lawrence, represents Turner’s ultimate vision and ambition: ‘A white incandescent surface, the same whiteness when he finished as when he began, proceeding from nullity to nullity, through all the range of colour.’

The picture I remembered seeing was like a representation of Turner moving – or, better, being drawn – towards this beckoning but unachievable vision. It gives visual expression to the same longing for transcendence articulated by Shelley (in 1821, in Adonais) as ‘the white radiance of Eternity’. This is not the only way in which the painting seems to be an essay on itself and the way it is perceived.

Our memories of works of art have an existence that is independent of, but contingent on, the works themselves. The ratio of independence to contingency is perhaps determined not just by us – by the vagaries and deficiencies of memory – but by the art itself. So it is no accident that this painting has failed to imprint itself on my memory with the precision and tenacity of a Canaletto, say, or a Holbein. The walls – assuming that the picture reproduced here is the one I saw back whenever it was – are insubstantial. The figures are insubstantial. Nothing is as substantial as that core of molten light. Everything else, all that is solid, looks like it could melt into air. The interior depicted has been painted over a view of a landscape, so that it resembles a murky X-ray of how it came into being. The painting is a palimpsest, seemingly containing traces or memories of its own earlier existence. And it’s obviously unfinished, suspended in the process of becoming what it is. The location and setting are neither given nor ascertainable. The title, Figures in a Building (Turner’s or cataloguer’s shorthand?), could hardly be less specific. The exact date of composition (c.1830–5) is unknown. According to Tate’s online catalogue, it is “one of several works where Turner seems to be developing a historical subject without any very clear direction, as if hoping a theme might occur as he moved his paints around on the canvas”. Even the artist, in other words, did not know what the picture might be about, working on it in the hope of a revelation that was never achieved.

Given all of this, it is hardly surprising that I couldn’t remember the painting clearly – it’s inevitable. Isn’t that exactly what the picture is about, the way that some experiences – of art and life – remain unassimilable? (And, while we’re at it, unphotographable: almost everything that makes the painting interesting is lost in the version you are seeing.) For all its haziness, the painting is a precise and lucid depiction of two refusals (both of which have their equivalents in Tarkovsky’s film). First, of the world’s inexhaustible refusal to succumb to the means of representation (if it did, we would be faced not with the end of history but the end of art). Second, the refusal of certain artworks to be reduced to memory. That, I think, is what makes the painting unforgettable.

Figures in a Building is no longer on display at Tate Britain. It is back in the vaults where, presumably, it blazes away like the light emerging within it.