Stubbs painted the subjects that English patrons required English artists to paint. He painted wives, selves and horses. Above all he painted horses. But his true subjects were not always exactly what they seemed to be. His greatest pictures, like the extraordinary, life-size painting of the racehorse Whistlejacket, or the masterpiece of his later years, Hambletonian, Rubbing Down, have a haunting, haunted, visionary quality entirely unique in 18th-century art. They do not describe animals, or at least they do not only do that. Stubbs's subject matter may seem small, but it is actually the largest subject of all: life, in its biological and moral essence.
One of Stubbs's greatest gifts was his ability to make reality seem charged with the intensity of myth, to make the present seem as mysterious and as beautiful as the classical past. In his hands, Newmarket Racecourse became a sacred place. He made the rubbing-down house on Newmarket gallops look like a temple. Seen through his eyes, jockeys, grooms and stable- lads seem engaged not in anything as mundane as work but in a form of votive ritual, at the centre of which always stands the horse, the object of reverence.
Not a great deal is known about Stubbs but not much needs to be known since he said so much in his art. He was born in Liverpool and he studied anatomy as a young man, living in an isolated farmhouse in Lincolnshire, cutting up and drawing dead horses. Anatomy was his first and his last preoccupation (he spent much time during the last years of his life preparing a treatise on the subject), and this marked Stubbs out from his contemporaries. Most other British painters of the time had learnt to paint by looking at other paintings. Stubbs learnt to paint by looking with intense closeness at reality. The closeness of the scrutiny to which he subjected all things and creatures is evident in the drawings that survive by his hand. These are among the masterpieces of graphic art.
In 1765 he painted a picture of a famous horse called Gimcrack winning a valuable race at Newmarket. Gimcrack on Newmarket Heath, with a Trainer, Jockey and a Stable-lad was painted for the horse's owner, the second Viscount Bolingbroke. It squeezes two events impossibly together: the horse and jockey each appear twice, once winning the race and once being greeted by lad and trainer. But despite this naive device, it was in its time an original painting. Stubbs has left out the crowd that saw Gimcrack win the race, so the action takes place in an oddly empty landscape. The omission is a revealing one and it takes us to the centre of Stubbs's vision. There are never any crowds in his art. He was a painter of solitude, a painter whose tendency was always to isolate. There is a kind of melancholy at work here too. Only Stubbs could have painted the strange, rather sad, sleepwalking figure of Gimcrack's jockey.
Stubbs was an extremely acute observer of 18th-century England. He painted someone on almost every rung of the social ladder, from the aristocrat to those who harvested his grain, and there is no more accurate register of the many subtle gradations of the English class system in the century than his oeuvre. But he was never quite a sociable painter. There is a perpetual aloofness about him, which communicates itself to those whom he painted.
The intensity with which Stubbs saw people and animals forced him to see them in a state of disconnection, cut off from one another. This may be why the act of touching, in his art, is tremendously and almost electrically charged. In that act the gap that separates all living entities from each other has been breached. The painter invests it with great and tender momentousness. Whistlejacket and Two Other Stallions with Simon Cobb, the Groom is one of the most affecting pictures of this. It is painted on a blank background - like the life-size Whistlejacket and the Brood Mares and Foals, and for the same patron - that enhances the isolation of the forms. Only man and horse touch. The groom rests his hand on the flank of Whistlejacket, to reassure or to comfort. Stubbs has concentrated much feeling in that hand placed on horseflesh. This is English painting's truest equivalent to the creating hand of God the Father, reaching out to spark life into Adam on the ceiling of Michelangelo's Sistine Chapel.
The largest of all Stubbs's paintings, Hambletonian, Rubbing Down is another great masterpiece of sympathetic art. It is also one of the most dreamlike and - despite its large scale - one of the most compressed of his paintings. Sir Henry Vane-Tempest commissioned it from Stubbs in 1799 after Hambletonian had won him a small fortune racing against another celebrated thoroughbred of the time called Diamond. Hambletonian had been whipped and spurred brutally by his jockey and he had finished the race almost dead, lathered with sweat and blood. Stubbs left out the blood but painted the exhaustion. The picture's true subject is the bond of affection that exists between the horse and its attendants. The horse is being consoled by a small, hard-faced man and a coarse-featured but tender boy. They have led their own hard lives and their sympathy for the horse is one of their ways of loving themselves.
Many of the animals that Stubbs painted were the trophies of a newly powerful and growing British Empire. They were symbols of the spread of British influence overseas, of the new worlds opening up before the gaze of explorers and colonisers such as Captain Cook or Sir Joseph Banks. Stubbs saw such creatures - monkeys, lions, tigers, rhinoceroses, arriving to form the first zoos - in all their animal otherness. He made exotic animals look peculiarly unexotic. He saw them as being simply (and rather sadly) out of place and he saw them with compassion, although he never resorted to the low, cute, Victorian trick of anthropomorphising them. This is what makes Stubbs's pictures of animals so much grander and so much more profound than any other British pictures of animals. There is no more affecting image of loneliness, of confusion, of a sense of being out of place, than his extraordinary portrait of a zebra, painted with such incongruity amid the greens and russets of an English wood. If Gainsborough reincarnated the fantastical tradition introduced to Britain by Van Dyck, Stubbs was another Holbein. His realism was, like Holbein's, a form of moral vision.
Stubbs's sympathy extended naturally not just across the barriers of class, but across the barriers of species as well. He accorded the same even attention to each living creature that he painted, so that in his art a dog can easily be as dignified as an aristocrat. He was a great leveller and one of the greatest artists of the Northern levelling imagination. Sometimes it is possible to sense the painter actively questioning certain notions of social and natural hierarchy. Freeman, the Earl of Clarendon's Gamekeeper, with a Dying Doe and a Hound is a painting entirely about hierarchy and about hierarchy under threat. It is a picture of the deer that dies to feed the man who cares for the dog, composed to form a triangle with man at its apex. Night is closing in on all of them and the certainty of man's innate superiority to the beasts, compositionally insisted upon, but implicitly subverted, suddenly seems less than totally certain.
Stubbs was a great artist, by which is meant more than a great English artist. He was a great world artist, in the sense that a painting by him can hang next to a great Titian or Rembrandt or Rubens and not be embarrassed by the comparison. This is where Sir Alfred Munnings made his great mistake about the nature of the British art tradition. The subjects of Stubbs's art might have been my wife, my horse and myself, but that alone was not the point. Stubbs's pictures of horses have nothing in common with Munnings's cold, dry, academic paintings. What makes them great is not their subject matter, but the tremendous weight of feeling that has been invested in them.
Stubbs was not too complicated an artist. In the end he knew just a few truths. But he knew them, and he was moved by them, as profoundly as any painter who has ever lived. He knew that we are, all of us, just bodies moving through space. He knew that, finally, we are all alone.
The next, and final, extract from Andrew Graham-Dixon's book, 'A History of British Art', will be printed in the 'Independent' on 14 May. 'A History of British Art' is published by BBC Books at pounds 25 (copies can be ordered, post free, from 01624 675137). His series continues on BBC2 at 7.30pm on Sunday