Bleu, saignant, à point, bien cuit: rare, medium- rare, medium, well done. Except, if you order a steak in France, you'll find the translations approximate. There is no English word for beef as rare as bleu, as there is none for art as raw as Art Brut.
"Uncooked art"? When the Frenchman, Jean Dubuffet, coined the term in 1945, he probably meant brut as something more like "unrefined" – à l'état brut, "in its natural state". Anglophones went for literal translation – "Raw Art" – before giving it up as a bad job in the 1970s and opting for "Outsider Art". This term, longer and vaguer, begged the question of what Outsider Artists were outside of. An academic tradition? The art market? Society? Prison? Their minds? And the answer to all of these was "yes", or perhaps "oui".
Dubuffet, a good French bourgeois and as sane as any other artist, discovered Art Brut by way of Bildnerei der Geisteskranken (The Arts of the Mentally Ill), a book by a German psychiatrist Dr Hans Prinzhorn, published in 1922. Here was an art made beyond the norms of society, or even of socially constructed sanity – an art, in short, of outsiders.
Dubuffet was delighted, but he was not alone. Freud's recent mapping of the unconscious had unleashed a flood of interest in irrationality, manifested, among other places, in the automatic poems and paintings of Surrealism. Art Brut, the name Dubuffet gave to the work of the excluded artists he began to collect and promote, was part of that impulse. (Most of these works are in the Collection de l'Art Brut in Lausanne.) This in turn fed into a much older equation of madness with genius, trackable all the way back via Wordsworth and King Lear to Socrates' linking of prophecy to lunacy.
Where Dubuffet commands our particular interest, though, is not in buying (or even part-naming) the art we now call Outsider so much as in making it. Or, rather, something that looks very like it. Here you will detect a catch. Being a faux-naïf artist is one thing; being a faux-mad artist is quite another. It smacks, at the very least, of poor taste. And there is a further problem.
So closely was Dubuffet's name linked with Art Brut that the idea took vague hold that he was himself insane, or at least that soft-edged thing known as an Outsider. As a result, he enjoyed a huge vogue in the decade that culminated in psychedelia, and Timothy Leary's command to turn on, tune in and drop out. This was neatly book-ended, in Britain, by his first exhibition here, at the Institute of Contemporary Arts, in 1955, and his last, at the Tate, in 1966. Since then, there has not been another monograph show of Dubuffet's work at any British public gallery. There is nothing sadder than an old hippy.
So Pallant House's new show, Jean Dubuffet: Transitions, is variously timely. Like the Courtauld in London, the gallery specialises in small, clever, tightly focused exhibitions. This one is built around a single group of works, known as L'Hourloupe, made by Dubuffet between 1962 and 1974. They straddle the high point of his reputation and the moment it began to fade.
Until L'Hourloupe, Dubuffet's favoured medium had been the so-called haute pâte or Matter Painting, in which he mixed sand and gravel with pigment to produce a thick, shitty surface. These were the works he showed at the ICA, to ecstatic applause: it was Dubuffet who put the brut in Eduardo Paolozzi's Neo-Brutalism. In his new series, though, he worked up doodles made while chatting on the phone into full scale Biro-pictures and, occasionally, sculptures. The Hourloupe works are, accordingly, in a ballpoint palette of red and blue on white, familiar to anyone who has worked in art therapy.
They are also surprisingly fine. Any painting or drawing is a negotiation between the marks it is made of and the image they add up to. That is as true of a brush-markless Poussin as a brush-stippled Seurat. The same contract exists between man and society: we want to be both ourselves and part of a bigger picture. Dubuffet's Hourloupe series runs those two negotiations into one.
Starting with a single mark, a face in a crowd, he works outward to the complete image, the societal whole. In pictures such as Site habité d'objets, you get the sense of recognisable shapes both generating each other and losing their identity, becoming more abstract. These images are equally of something – a bed in Le lit, a gas stove in Réchaud-four à gaz – and of nothing. You suddenly see the misunderstanding. Dubuffet never wanted to be mad in paint, to pass himself off as an Outsider: he was telling the story of madness, of its inevitability in an animal that is both selfish and social. He may also have been struck by the story's strange beauty.
To 3 Feb (01243 774557)
Charles Darwent is Seduced by Art at the National Gallery
Wade in to the annual debate surrounding the Turner Prize – and see if you can pick a winner – at Tate Britain. This year's four shortlisted artists are Spartacus Chetwynd, Luke Fowler, Elizabeth Price and Paul Noble. Also, Nottingham hosts an impressively wide-ranging, vibrant exhibition of Haitian art, with the arrival of Kafou: Haiti, Art and Vodou at Nottingham Contemporary. Both shows run until 6 January 2013.