In a recent article in the London Review of Books, Terry Eagleton wrote about the linguistic similarity between Samuel Beckett and Theodor Adorno. "What is most drastically impoverished in Beckett is language itself," he wrote. "Adorno's style reveals a similar austerity as each phrase is forced to work overtime to earn its keep . . . Like Beckett's, Adorno's is a language rammed up against silence, a set of guerrilla raids on the inarticulable." For both these writers, the deficiencies and untruths of language had been revealed in the "crazed assurances of fascism and Stalinism". Language itself had become discredited. Only what was indeterminate could in any way approach the truth. It was this that led to Beckett's much-quoted remark about trying to fail better. His favourite word, apparently, was "perhaps".
"Perhaps" might also be the favourite word of the American painter Cy Twombly, whose marks and expletives, handwritten quotations and dissolving textural pencil lines stutter across the surface of his paintings like signs in search of meaning. A form of visual poetry, reminiscent in its arcane mark-making of that of the Franco-Belgian artist Henri Michaux, his appropriation of calligraphy - a point where art and writing become indi visible - creates something new in the interstices between both. Twombly never asserts; rather, his paintings are an intuitive exploration. He is frequently described as a "graffiti" artist, but that is too narrow and speaks simply of a style rather than philosophical content. Language, and its inherent inability to articulate, are what concern him, as much as experiments in the application of paint.
For Twombly, just as for Beckett, there is a great compulsion to find a means of expression, but an awareness of the near impossibility of doing so. He once said of his work: "It's not described, it's happening . . . The line is the feeling." Twombly's paintings are essentially about pro cess, investigation and discovery, hesitant diagrams that attempt to chart intellectual and emotional experience.
"And what is it you do?" Jackson Pollock asked the younger painter on each of the four occasions that they met in 1956, when Pollock was considered to be the high priest of modern American painting. Twombly's enormous body of work, with its scratches, scribbles and frenetic lines, can now be seen as a subversion of the dominance of abstract expressionism and Pollock's macho loops and swirls of paint. Here was the artist not so much as hero, but as errant schoolboy, scribbling in lessons and writing "fuck" on the schoolyard wall. Twombly understood that in the modern world there can be no dogmatic certainty, just as Adorno had asserted the impossibility of lyrical poetry after the Holocaust.
Born in Lexington, Virginia in 1928, Twombly studied in Boston, Washington, Lexington and then New York. It was there that he met Robert Rauschenberg at the Art Students League in 1950. Later he attended the influential Black Mountain College in North Carolina, where he studied under Franz Kline and Robert Motherwell. A number of things led to his interest in calligraphy: the influence of Motherwell, and that of the surrealists, with their investigations into automatic writing and the nature of chance, along with his conscription as a cryptographer into the US army, where he studied and deciphered code.
Influenced by his travels in North Africa, the early paintings in this major retrospective of Twombly's work at Tate Modern, such as Min-Oe, emphasise a fascination with architectonic forms as well as classical, archaeological and tribal artefacts. They recall the work of artists such as Jean Dubuffet and Alberto Giacometti. His untitled sculptures - makeshift bits of wood lashed together with strips of dirty cloth and string - look like African fetishes, but show the influence of Rauschenberg, that guru of detritus, with whom he travelled during 1952-53.
In the spring of 1957, Twombly left America and set sail once again for Italy, leaving the citadel of modernist painting for a world steeped in ancient mythology and struggling with the aftermath of war. White and bleached, his paintings from this period are full of the effects of the harsh Mediterranean light. His Poems to the Sea series, executed in a single day in 1959, is crammed with classical and poetic references. "Whiteness," said Twombly of these spare, lyrical works that elide calligraphy, poetry and painting, "can be the classic state of the intellect, or a neo-Romantic area of remembrance." There is an austere purity to all this classical whiteness as his snaking pencil lines, erased by the smears of white paint, unravel into a syntax of approximate meaning.
Later, as he worked from a studio in the hot summer streets of Rome, in a part of the city frequented by prostitutes and petty thieves, his paintings became more scatological and transgressive, with scribbled genitals and orgasmic ejaculations of paint. His 1961 Ferragosto series, named after a Roman fertility festival, seems to leak with putrefaction and overripeness, the canvases smeared with the blood and faeces of some ancient Dionysian rite. As Roland Barthes observed of Twombly, he injected an aspect of the aberrant by "deranging the morality of the body". In contrast, the Bolsena paintings (1969), with their manic scribble of apparently symbolic signs, their scattered vectors and meaningless measurements, look like the crazed workings of some mad scientist who is determined to find order in chaos. Embedded in these works is the feeling that the struggle between opposing forces - reason and experience, Eros and Thana tos - is never far away.
The frantic sense of working out becomes ever more pared down in his Treatise on the Veil (1970). The initial influence for these huge paintings came from an Eadweard Muybridge photograph that Rauschenberg gave Twombly, which apparently showed a bride passing in front of a train. Finding in the mid-1960s that he was being dismissed as outmoded by the cognoscenti of the New York art world, he violently changed trajectory to embrace the grid, that archetypal emblem of modernist painting, along with more stringent minimalist forms. These works look like enormous blackboards covered with sparse diagrammatic rectangles, and imply some sort of geometric calculation, or even the storyboards for a film.
A graffito mark, according to the critic Rosland Krauss, is "a registration of absence". It is the trace that remains as imprint and aftermath. What is left by the presence of the person who has done the tracing is a residue, or, as Beckett might have implied, a pregnant silence. In the beautiful and melancholy Nini's Paintings (1971), an elegy to the wife of Twombly's gallerist, his tumbling seascapes of swirling marks stutter towards articulation only to dissolve into the incoherence of grief. In contrast, the rich reds and dark blues and greens, the thick impasto and rolling brush marks of his 1980s paintings of the sea, based on the legend of Hero and Leander, seem to return to Turneresque experimentation with the expressive possibilities of paint. This watery theme is taken up in the astonishing suite of nine green paintings produced for the 1988 Italian Pavilion at the Venice Biennale that seem to fuse Monet, abstract expressionism and the baroque, in an almost mimetic evocation of the watery canals of Venice, with their deep, dark shadows cast by the crumbling Renaissance palaces.
The cycles The Four Seasons (1993-95), painted in Twombly's mid-sixties, come at the end of the exhibition. They explode with intensity, like a great choral work, assaulting the senses with their sensual colour and scribbled fragments from the poets Rainer Maria Rilke and Giorgos Seferis. The two series, one from New York's Museum of Modern Art (1993-94) and one from the Tate collection (1994-95), each comprising four great paintings, have been reunited here for the first time. But nothing quite prepares one for the shock of the last room, with its orgiastic swirls of red paint that loop and ooze across the canvas, like the blood from some debauched, bacchanalian sac rifice. From the near silences of Cy Twombly's early monochromatic works, where marks stutter towards meaning and articulation, the exhibition ends with a great crescendo of euphoric, orgiastic and frenzied release.
"Cy Twombly" is at Tate Modern, London SE1, until 14 September. For further information, log on to: www.tate.org.uk