What I was not prepared for, though, was the reality of the Godfather of British Pop Art. Individual success can often be measured by the amount of myth it attracts and Paolozzi is no exception. To many he might appear irascible, acerbic, aggressive, but he is also - undeniably - intelligent, lucid, witty and instantly likeable.
Two facts: Paolozzi is a great artist. Forget Freud and Kossoff, this man has just as much claim to be our "greatest living artist". And Paolozzi is a great Scotsman. Forget Billy Connolly. This is the real "Big Yin"; a great bear of a man, with stubby, sculptor's fingers and a putty-soft face of deep furrows and creases. Paolozzi, 72, immediately dominates a room and it seems bizarre that, seated at the lunch table in Jason and Rhodes's gallery, this imposing presence should speak in a soft Scottish burr, coming out with polite platitudes more suited to a country parson or an Italian mama. "Another cake? More pasta?" But such delicious incongruities have always characterised his life and work.
Paolozzi is all about the unexpected - as anyone brave enough to sign up for his masterclass in Edinburgh this summer will quickly discover. Sunday painters need not to apply. "A masterclass is a very difficult thing," he says ominously. "A lot of people like to combine a holiday with making art and there's also an assumption that art isn't much good unless it's fun. Amateur artists often start off with a sublime subject and end up with something banal, whereas a real artist does it the other way round."
Eduardo Paolozzi has been looking at the banal and transforming it into the sublime for over half a century. Born near Edinburgh in 1924, he grew up in the ice-cream parlour owned by his Italian immigrant parents, immersed from the beginning in popular culture. It was, as he says, "a lasting influence", reflected in his most recent installation, "The Jesus Works and Store: an attempt to describe an indescribable film", included in Spellbound at the Hayward Gallery. A contemporary cross between a cabinet of curiosities and a film prop store, it was a link between ephemera, Pop and artefact, in which consumer objects were charged with a personal significance and underlayed with an abiding sense of classical aesthetics.
The exhibit, says Paolozzi, "was in a sense a lost autobiography - a lost childhood; a world of cigarette cards and cinemas. Something quite subliminal. It was naive art with a whiff of the psychotic. That relationship between childhood experience and art is lovely open territory. It's fascinating how things change when you see them in a different context."
If any one idea sums up Paolozzi, it is this decontextualising of objects to imbue them with other meanings. And, as this implies, if there is one thing he hates, it is the tendency to categorise: "To describe Kandinsky as an 'abstract painter' falls short. But what phrase do you use? Art in the 1990s is very complex. It's such a swing from Lucian Freud to Damien Hirst. Think of Hirst's spot paintings. Haven't we seen all that before - in the 1950s with the Cohen brothers? People doing the same kind of work over a period of time has made the labelling of art almost impossible."
Paolozzi himself is notoriously hard to define. At the Independent Gallery in 1952 he broke new ground with a silent projection of found images in random order. His early, fetishistic style of sculpture, influenced by Dubuffet, is also reminiscent of Giacometti and Germaine Richter. Gradually, these totemic figures metamorphosed into the slick mechanical men of the 1960s. At the same time he was making his seminally important Pop Art collages (he prefers the term Bunk). In 1965, he produced collage-based screenprints and, in the 1970s, his quasi-cubist sculptures. Then, in 1979, in an Edinburgh exhibition, he made a statement - Junk and the New Arts and Craft Movement - in which he defined himself as the inheritor of the populist torch of William Morris, again implying that high culture was popular property and vice versa. Having been professor of Ceramics at Cologne in the late 1970s, he now occupies a similar position at the RCA. Over 50 years, Paolozzi has worked in sculpture, graphics, books, films and the written word.
He does not see why all artists should not make similar crossovers. He cites Cocteau and, throughout our conversation, shows evidence of a vast fund of knowledge. Hardly surprising given that he has spent the last 40 years as a teacher as well as an artist. He proves the lie to the maxim that "those that can, do; those that can't, teach". It was Paolozzi who, as a visiting professor in Hamburg from 1960 to 1962, taught ill- fated Beatle and abstract painter Stuart Sutcliffe, commenting on his work: "One of my best students ... a very perceptive and sensitive person."
His own artistic education was somewhat unorthodox. Taking over the family ice-cream shop after the death of his father in 1941, Paolozzi attended evening classes at Edinburgh in 1943, only being free to enter the Slade full-time in 1944. Removed with the college to Oxford, Paolozzi spent most of his time in the Pitt Rivers Museum, fascinated by African art and fetish scupture. It was, he says, "a bit of a cultural struggle. I was the only student who slipped off there. Others were indifferent to it.
"When I left the Slade and went to Paris in 1947, I had a mission to see modern art and in particular Surrealism, and to meet real artists for the first time. They were all still alive and extremely approachable." He met Braque, Arp, Brancusi, Dubuffet, Leger, Giacometti, Mir and Tristan Tzara. He became friendly with Duchamp's ex-mistress Mary Reynolds, often visiting her house with its collage-covered walls. He realises how lucky he was. "Giacometti was unbelievably amiable. We met twice a week. We didn't have diaries - you just met at the Cafe Flore or the Deux Magots. We were all there every night." The casual "we" is taken to include not only Sartre and Camus, but such young Scottish artists as William Gear, William Turnbull and Alan Davie.
Paolozzi, a Surrealist at heart, schooled in the Europe of the 1950s, exemplifies that Scottish artist's internationalism which makes the current plans for a gallery devoted solely to Scottish art so inappropriate. As a Scottish artist, he has been claimed as a national asset in a new wing housing his work at the Scottish National Gallery of Modern Art that will open next year. While excited by the prospect, he is cautious about being labelled. "Everyone has their own notion of nationhood, but it would be absolutely disastrous to be considered purely Scottish." And what exactly does Scottish "art" mean? "The Scots were once famous for building ships for the whole world. While Mackintosh's Glasgow Art School was being built, so were three cruisers for the Japanese Navy."
Paolozzi leaves the lunch table and dives into the storerooms of Jason and Rhodes to emerge with his 1970 portfolio of immaculately finished prints of US military hardware - Zero Energy Experimental Pile - a homage to American imperialism. This illustrates the leitmotif of his entire career - that all objects have an interrelated continuity within the human psyche.
"Modern art isn't easy," he says. "I remember Freddy Ayer [the logical positivist] telling me he found modern art very confusing. He longed for a big book on modern aesthetics so he could look up everything to see if I had the right amount of classifications and points. It just doesn't work that way, does it?"
n Masterclass, Edinburgh College of Art 15-26 July (lnfo: 0131-221 6111). 'Paolozzi Collages', Talbot Rice Art Gallery, Edinburgh (0131-650 2211) from 7 Aug