ART / Seeing, but not believing: As the chronicler of madness and despair, Goya was the first modern painter. Andrew Graham-Dixon on 'Goya: The Small Paintings'

The man in bed does not look well. His whole body has gone into a violent and, it is to be assumed, terminal spasm. He clenches a fist involuntarily and his right leg, knotted with cramp, sticks out from under disarranged bedclothes at an unnatural angle. His face is twisted into a scream.

He is not alone although he might prefer to be. He shares his bed with a horned demon, a monster with the head of a goat, a red-eyed ghoul and a thing with bat's wings. Help may or may not be at hand. By the side of the bed there is a priest, dressed in black, who holds up a crucifix in benediction and looks on, half amazed, half horrified, as a miracle takes place. The figurine of Christ which he clutches, gingerly, has raised a tiny wooden arm to fling a rain of blood across the dying man. It arches through the air to spatter him with thick red gobbets, a blessed and horrible shower.

Goya painted St Francis Borgia Attending a Dying Impenitent, one of about 80 pictures in the Royal Academy's 'Goya: The Small Paintings', in 1787 or 1788. The image is full of omens, a dark fantasy portending the still darker and more fantastical world of the painter's later and better known creations: a picture which has its roots in the violent and superstitious Catholic faith of old Spain, but which still manages to strike a new, dissident and nearly atheistic note.

This is not the sort of painting which seems calculated to cure those of little faith of their doubts. It is hard to say which is more distressing: Goya's appalling vision of hell or his equally gruesome vision of potential salvation; the menagerie of medieval demons in the bed or the haemorrhaging wooden homunculus in the priest's hand. Perhaps, the painting seems to imply, in its contrast between the reality of a dying and convulsive man and the mad extravagance of the phantoms that beset him from all sides, there are no other worlds, either better or worse than this one. Perhaps there is only death, and the consoling or terrifying fantasies that we have invented about what lies beyond it are merely figments of the imagination.

The RA's exhibition confirms that Goya was constitutionally unsuited to the expression of uplifting or enlightening themes. Goya was always, inevitably and even involuntarily, himself, and there was always something disconcerting and disturbed about the nature of his imagination. The show contains many of his sketches for religious pictures, executed, when he was a relatively young man, in a style derived from Spanish Baroque and Italian Rococo art. They are unfamiliar and besettingly odd, these images of airborne saints and putti, floating heavenwards on the brightly coloured, overlit, stage- prop clouds of stock 18th-century religious art. A false note is always struck. Goya's heaven is always too much like a hell.

There is a strong sense, in these works, that Goya himself does not believe in the religious fictions which he is painting. He responds distractedly to his subjects, like someone with his mind on other and more sinister things. The cherubs that hover in mid-air in his very early Virgin of the Pillar are nasty, mischievous imps with sour faces and flushed, livid bodies: not the standard flying toddlers of Rococo religious painting but fat worms with wings and baby's faces. Goya's oil sketch for The Appearance of St Isidore to St Fernando, an obscure and opaque picture of one of those thousands of obscure and opaque minor miracles still celebrated annually in small towns all over Spain, is stranger still. The saintly apparition looms, sudden and enormous, swooping through the air in his great outstretched yellow cloak and bishop's mitre, banking up and around the edge of a tent to astound the assembled devout with his appearance.

There is something of the cartoon character about him, a caped crusader saint, flying low - and he will reappear, in a slightly different form, as one of the flying clerics in Goya's Los Caprichos, more openly satirised and made to look like a witch on a broomstick. But even when Goya was, apparently, trying to paint such subjects with a straight face he could not quite manage it. His religious pictures are clearly the work of an irreligious man.

The RA's show, with its preponderance of minor and little known works, is fascinating despite its limitations. It presents the spectacle of an artist working against the grain of his own temperament, but it also shows how Goyaesque Goya always was. The light, decorative tapestry designs that he made in the 1780s and 1790s deserve to be better known because they are so surreally and incongruously unpleasant. They are not light and decorative at all, beneath their bright surfaces and uncomplicated subjects, but strange and alienated and incorrigibly weird, pictures of pastoral idylls where things always seem slightly but nastily awry. To look at these pictures is to see how Goya was incapable of painting an ideal world, and incapable of adopting the styles and subjects of artists who could without turning them to his own obscure purposes: this is Watteau's Isle of Cythera, painted in the loose and bright and insouciant manner of Boucher, but still filtered through a dark and morbid imagination that is entirely Goya's own.

There is something black and blank about the eyes of the frolicking and rustic peasants, a disquiet in the souls of the leisured aristocrats having a picnic. A game of blind man's buff, played under blue skies and beside a placid lake, seems sinister and allegorical, a torture inflicted, inexplicably, on someone who thought he was in paradise. The Straw Manikin, tossed in a blanket, becomes more than a prop in an innocent game and turns oddly human: a disjointed, sad-faced dummy, he is an inscrutable victim who flops and jerks and turns, in mid-air, to fix you with dead eyes.

Goya, it might be said, was a disillusioned artist made great by historical circumstance. He lived during one of the great ages of disillusionment, and was perfectly adapted to create the emblems of a new and saddened sense of what it means to be human and alive. In the later stages of this show, he finally becomes the Goya of legend and, in one sense at least, the first modern painter: the painter of madness and despair, of folly run wild, of a universe ruled, not by God but by violence and pointlessness and death. Goya's pictures of bullfights and insane asylums, of frenzied flagellants, of the dark and hellish councils of the Inquisition - these have become, with the passage of time, among the great symbolic images of the unregenerate, tormented modern world, and of a certain kind of pained, modern self-consciousnes.

But what gives these later paintings such force and such potency, and what makes them so inimitable, is the fact that they did indeed spring from disillusionment and were created out of the wreckage and death of an older kind of culture and another kind of painting. They draw their strength and tension from the painter's own sense of their newness and dissidence and from the knowledge that his way of seeing is not the old way of seeing. Goya often plays this up, through pastiche, as if he has learned to use and adapt the involuntary pastiche of his earlier work and make of it a tactic. The carnival lunacy of Procession of Flagellants is a disaffected, jaundiced parody of an old and discredited form of devoutness. The Madhouse, where crowded loons enact the roles dictated to them by their diseased fantasies, is also a sort of religious parody: an image of the old and frenzied imagination of the Catholic faithful redefined as a literally mad credulousness.

The paradox of Goya's imagination, so vivid and inventive, so swarming, is that it expresses a profound distrust of the claims made for the imagination. The imagination is what Goya finds most dangerous and suspect in human beings: it is responsible for the delusions and fantasies that lead to war, the myths that lead to religious servitude, the ingenuities of torture. He painted the terrors of the mind, perhaps, to release himself from them and he died, like the man with the clenched fist and outstretched foot that he painted back in 1787 or 1788, impenitent: grimly proud of his own faithlessness.

'Goya' is at the Royal Academy, Piccadilly, W1, until 12 June

(Photograph omitted)