Joachim Schlör, in his seminal study Nights in the Big City, writes how the coming of street lighting to Western cities in the mid-19th century was attended by an upsurge in moral panic. Far from experiencing the illumination as the banishment of infernal darkness, many burghers perceived a dangerous and unnatural phenomenon. The lit-up city was a realm within which the established divisions between interior and exterior were broken down: no longer did the good citizen lock up his door at nightfall, and wait for the cock's crow.
By the same token, street lighting allowed for the mingling of classes and sexes in new and promiscuous ways - so nightlife was born. The ability to move easily about the city, traversing zones heretofore off-limits, and to penetrate sequestered neighbourhoods crystallised urban self-consciousness. The city dwellers were now permanently checking themselves in the lit windows of shops, and seeing there, imprisoned, Escher-like, their own reflections and the images of that which they desired.
Even in our own era, 140 years later, the city by night still appears as a distinctively modern terrain: at once minatory and compelling, too bright and too obscure. The shadows are sharply adumbrated, the colours are leached out, the people stroll, hurry and lurk, players on a stage set that has been erected For One Night Only.
Any serious flaneur walks by night as much as by day; for by day it's too easy to be drawn into a complacent acceptance of normalcy. This much we plainly know: the panel truck disgorging toilet paper; the smoking secretary with laddered tights; the dosser senatorial, sporting a sleeping bag for a toga. But by night these are shape-shifters, capable of defeating our expectations. They may assume the faces of loved ones, and so effortlessly enforce intimacy - or seem strange to the point of being alien, and so provoke repulsion. We may fancy ourselves rational and civilised, yet immediately beyond the sodium firelight, the wolves are always pacing the paving stones.
I walk by night. I remember years ago, before there were buses or Tubes on New Year's Eve, walking over London Bridge, in the chill of the first 3am of the year, and seeing an entire platoon of Roman legionnaires marching towards me. At the front, a standard bearer carried the eagle captioned "SPQR"; at the back, a drummer in a leopardskin beat the rhythm for their sandaled feet. I was not alone, so could not dismiss this as fancy or hallucination. Yet neither my companions nor I were disposed to talk to each other as the ancient squad passed us by; nor did we hail them, nor did we speak of it again. It was a benison of the night.
I have trudged through the dust of Varanasi in Uttar Pradesh, by the 40 watt-lighted sheds, where everything mechanical that can be dismantled is bolted together again; and by the candle-guttering hovels, where women knead chapatti dough as dun as the walls of their own, malleable dwellings.
In the heat of the night, cities exhale: ghee sizzles and releases the food smells into the dark, where human minds, starved of vision, open up their nostrils to see. By night all hot cities are synaesthetic in this way: scrambling up sound and smell and touch, so that a milk train, clacking over points, feels up your spine with metallic fingertips.
I have walked uptown from the Village, on Hallowe'en night, passing by the raggedy company of ghoulish New Yorkers, all Gothed-up in Gotham, their eyes black-rimmed, their teeth bloodstained. We were carrying our eldest son, then a newborn baby, and Morticia after Cruella stopped to bill and coo: "Is that a real baby?"
Is this a real city? was the only possible rejoinder. In the chill darkness, New York forfeits any claim on our amazement. The pinprick lights of the vertiginous towers merge with the empyrean itself, while at ground level, fire hydrant after phone booth after Korean corner-shop provide the delusions of human scale. It's all about us, isn't it? Along the long ramps of the avenue, taxis wallow, their grimacing fenders gulp up the devilish steam clouds escaping from manholes, then their trunks release them in vaporous gouts.
But tonight I'm not in the east or the south or the west, not in Varanasi or London or New York; I'm in Glasgow, dining with the writer Alasdair Gray and his wife, Morag. I'm not thinking about night walking especially. We're sitting in the brasserie of the Oran Mor, the arts centre on the corner of Byres Road and the Great Western. Upstairs, on the ceiling of the enormous nave - it was once a Presbyterian church with a pituitary disorder - Alasdair has painted one of his distinctive murals: zodiacal figures striking hieratic attitudes against the vaulted blue sky.
There is the deep blue of the night sky in his mural, and Alasdair and his co-workers have scattered silvery stars across it. Of course, the anti-naturalism of this is all the more poignant in the heart of the city, where the constant haemorrhaging of electric light bleeds sodium into the darkness. We use different parts of the eye - rods and cones - with which to see colour; at night, in the absence of electric light, we see the world in a ghostly monochrome; or rather, we see it in a beautiful, silver nitrate monochrome, if only we allow it to swim out of the dark fluid for us: night sight takes time to develop - at least a half hour. Instead of this ulterior vision, the city splashes Day-Glo red, blue and orange across our eyes, and it's only in their lurid afterimages that we become creepily aware: the silhouette of the beast remains in the shadows.
Alasdair is speaking of Flann O'Brien and a conceit that he particularly likes in The Third Policeman: "You recall," he squeak-says, in his distinctively staccato manner, alternating between parody and self-parody, "the character of, um, de Selby, and his, ah, theory that night, far from being darkness, is, in fact, a morbid exhalation of some kind, 'black air'. De Selby didn't know that much about the, um, black air, although he had reached the conclusion - following certain ex-per-i-ments - that it must be a gas because when he lit a candle, it burned, and the black air, ah, dissipated."
Alasdair's words inspire me, and I decide to walk back to my hotel, the Hilton at Charing Cross. I like to stay at the Hilton, a tower block of faux-domesticity by the M8 flyover, when I'm in Glasgow. From its prow-shaped windows it offers the biggest views out over the valley of the Clyde, or out towards its mouth, or north, into the hills at Milngavie. I can't sleep well in hotels: sleep is too big a descent into the black air with nothing familiar around you. The French have it wrong, it isn't orgasm that's the "little death", but sleep - even an afternoon nap in a hotel is a micro-extinction for me.
In the severe rationality of the Hilton's shoebox rooms, the owlish visitor, alone and sick of the TV lightbox, can turn his attention outwards, and imagine himself flying up into the sky, buffeted by grey Zeppelins of cloud, their undersides bilious from the street lighting.
India, seen by night from high above, is a diadem of a subcontinent, jewelled by the faint gleam of its myriad villages scattered regularly across the Gangetic Plain. The lambency of the earth's cities is visible from space: a cosmonaut, or an American billionaire, who steps out from a space station for a short walk must find himself stroll-orbiting on this pavement of lights. A 20,000mph constitutional from the few remaining dark patches of the world - its increasingly tepid poles, and equatorial bald spots - to the mighty blaze of Western Europe, the eastern and western seaboards of North America, where untold ergs of energy are hurled skyward: Zeus's thunderbolts returned to him with a vengeance.
I say goodbye to Alasdair and Morag and leave. Suddenly, I'm standing outside the brasserie looking at a man with a fighter-pilot moustache, who's leaning, smoking, against a steel bollard. It's a chilly night in the north, and we've been forced to acquire the habit of exile, along with our other one. The transition from interior to exterior is that much more extreme by night. Thrust into the chill and unsettling city, what could be more understandable than the newly primitive desire to light a small fire and warm your lips round it?
He stares balefully over at me. His fighter must look like an enormous cigarette - so nicotinous is his facial hair.
"Why've they put 'em there?" He grunts, jerking a thumb at some metal tables and chairs outside the adjoining pub.
"I imagine they're looking forward to the summer," I say. He grinds out his butt and comes up to impress his walrus muzzle on me. "Oh, aye," he groans, "mebbe."
"It's the triumph," I say, sententiously, "of hope over expectation."
This pricks his interest and he peers at me with watery-eyed gratitude. Looking at his saggy denim arse as he shuffles back into the pub, it occurs to me that this may be the first time in weeks that anyone has addressed him as if he possesses a brain not sodden.
I set off to walk the two or three miles back to my hotel. It's that paradoxical time of year, poised on the cusp of spring, when some urbanites huddle up while others strip off. To some, the night is a velvet cloak to be draped around their bare shoulders, to others it's black ice insinuated between stubbly neck and furry collar. By a post office box, a waif stands with her chapped lips riveted together, and the bright pink stippling of goose bumps on her white, white calves.
I think of long evenings when summer is finally here. In London, where I live, there are no Dostoevskian "white nights" such as you get here in the north; instead, the heat seems to build into the dusk, a mounting rhythm as all the exhaust fumes, rubber, leather and grease pounded into the paving stones and tarmac reaches a critical mass, before exhaling into the cooling air. At those times, walking back from the West End, seeing the strollers on the Embankment in shorts and T-shirts, or the clones outside the Vauxhall Tavern, shaven-headed and bare-chested, the night-time city is a boudoir, with its sexed-up inhabitants in increasing states of déshabillé.
I head away from the main road, up glistening pavements between privet hedges. There's the faintest of mizzles, a percolation of water into the air, so that in the downlight of the streetlamps, sparkly, diaphanous curtains waver and distort. The houses are large and handsome; their porticoes are rendered in stone and supported by Grecian pillars. Urns and petrified laurel wreaths are poised on head-height gateposts. Through the clear panes of one sash window I see a couple, a wine bottle, incendiary news footage on a television by the fireplace. I covet their framed art-exhibition posters, their tufted rug, their family photos more than anything I've ever wanted before. Nothing and nobody is more covetable than a cosy dwelling, seen by night from the street without. The sash window is a shop window, and what's for sale here is an idea of cosy homeliness that can never be experienced, except by a voyeur.
On I plod, past the unutterable gloom of a silent, suburban church, down an alleyway and back on to the main road. The parked cars are now pearlised with raindrops; a take-out chef kneels to close his shop grille with a rattle; the enlarged photos in the furniture store are portraits of the ideal - yet absent - family that lives here. There are also pubs and shops along this paving-stone strand, young people stand out in the street, smoking and drinking from clear bottles full of some fluid rendered bilious by the sodium glare of the streetlamps. I'm entering their territory, and everything in their body language - the way they butt and rut, the way they preen and keen - suggests that they guard it zealously. Yet, I'm invisible, beneath my own magical cloak of middle age. By day strangers can be scrutinised, by night we are reduced to the crudest approximations - age, gender, height, bulk - and dismissed accordingly.
Turning down another quiet street - this time one lined by the flat façades of two-up, two-down terraced houses - I'm discomfited by the presence of a fellow night-walker; a woman, trim and well dressed, who clacks along the pavement on high heals. I feel that dreadful sense of reverse paranoia that always comes upon me when I find myself walking behind a single woman by night; and this time, as I am in a melancholy mood, it's intensified. Night walking is a luxury for a man such as myself, too old to attract casual aggro, too large to be easy prey. It's worth remembering that for many the night-time city is a genuine jungle, not merely a psychic adventure playground.
At the next corner, the orange wash of artificial light and the brown miasma of the shadows is slashed apart by the revolving blue blades that coruscate from the roof of a police car. Two officers stand either side of a rubbish bag full of humanity that's draped over a garden wall. Their fluorescent jackets give them the appearance of plastic bafflers arranged around a traffic accident. The cheap jewellery of broken glass lies scattered on the pavement at their feet.
I'm relieved by the presence of the police - it damps down my reverse paranoia. The woman ahead of us fumbles in her handbag for her key, and opens the front door of the house next door. I pass by, ignored by all. Come dawn, all that will be left of this incident are the contents of an abused stomach fertilising a herbaceous border. Oh! Those herbaceous borders, those privet hedges flocculent and strong-smelling by night, more bucolic than any country lane.
Then, a grand building, a huge, elongated dome, two L-shaped wings bracket a courtyard and flap away the night. It takes me what seems like aeons to proceed along its frontage, beside its punitive iron railings, under the stare of its hundreds of blank windows. Then, quite suddenly, we can see the city spread out below and to our right, a sparking grid of streets; while ahead, the motorway flyover strides on blocky concrete legs, its deck swishing with speedy, late-night traffic.
By night, the underside of the flyover is a cloistral space - but writ unbelievably large. I decide to work my way down the slip road, past behemoth Indian restaurants, and go underneath it on to a patch of wasteland. This - it occurs to me as I struggle over mounds of shattered masonry and through inappropriate thistle patches - is the real temple of modernity. This is the city's Baalbek, with its bulbous pillars, its Byzantine illuminations, its altar of traffic lights. I remember being in San Francisco, a few months after the earthquake, and walking by night beside a flyover such as this, but one buckled and broken. It felt like a total reversal of civilisation, a halting progress back to the primeval.
A scamper across the slip road, a traverse across a car park, up a ramp, and there it is: the bland uniformity of the hotel, rising up 20 storeys, each lighted window another desperate little tale. The electric doors whoosh open and I'm yanked into the lobby. Even though I've only been walking for an hour, it's enough to completely destabilise me. In here, everything is too close up, too in-yer-face, too large and bright and insistent. Shaven-headed businessman bouncers stand on a quarter-acre of carpet, giving each other strong-arm handshakes, breaking into one another's personality.
Our ancestors were right, it seems, to fear the lighting of the city; for, by banishing the night from the outside, we've sucked it into our own interiors.
This is the first of four nocturnal rambles in the series 'Nightwalks', each evening on BBC Radio 3 at 11pm, starting on MondayReuse content