Should Nam June Paik's name not be familiar to you, a useful thing to know is that he coined the term "information superhighway".

Another is that he was working with lasers in 1966, soon after their invention, and a third, that he conducted a series of experiments bending cathode rays with electromagnets. A last thing to know about Paik is that he was not a physicist but an artist, a follower of Joseph Beuys and Fluxus, a pioneer of media art.

It is not to belittle him to say that Paik had a talent for turning historical misfortune to advantage. Born in Seoul, he fled to Japan with his family at the outbreak of the Korean War. For a trainee classical pianist in the 1950s, Tokyo was one of the places to be. Paik topped off this piece of nifty timing by moving to Germany, finding himself in Düsseldorf just as Beuys hit his stride. Via the Kunstakademie, the young Korean met and collaborated with John Cage. In 1964, at Cage's suggestion, he moved to New York, taking up with the likes of Yoko Ono, Laurie Anderson and Merce Cunningham. He died in Miami four years ago at the age of 73.

New York was a particularly happy move for Paik. In the early 1960s, America was just waking up to the power of television. The year Paik arrived, Marshall McLuhan published Understanding Media with its ominous line that "the medium was the message". Where McLuhan saw threat in the idea – roughly, that television itself was what mattered, not what was shown on it – Paik saw hope. Turning McLuhan's dictum on its head, he countered that the medium was the medium, a tool of potential good if handed over to artists. Since television was inherently democratising, "artists" could include just about anybody. In the future, Paik said, the daily TV listings would be the size of the Manhattan phone book, anyone who wanted a channel being free to go out and get one. As to himself, he set about making work out of televisions, a genre palely imitated today by the likes of the Otolith Group.

You can see where the tendency began in twin shows in Liverpool, one at the Tate and the other at FACT. They should be viewed in that order, the Tate's archival exhibition starting at the beginning, with Paik's 1960 Hommage à John Cage, and leaving off in the mid-1980s, FACT's centrepiece being the late and lovely Laser Cone of 2001. What strikes you in both shows is Paik's understanding, not shared by all current artists, that cleverness, in making art, is not enough.

His work is undoubtedly clever, but it is also visually engaging. When Paik said that the medium was the medium, he signalled his intention to use television as a painter uses paint, to appeal to something more than the brain, to captivate the eye. Maybe he took this understanding from Beuys, whose forays into felt and fat were as much visceral as theoretical. The work in the Tate's first room – an open-reel tape recorder, stacks of records kebabbed on an outsized spindle, upright pianos rigged to switch on fan heaters when their keys are pressed – has a Beuysian sense of its own place in history, of being both artwork and artefact. Oil Drums, Hommage to Charlotte Moorman takes the drums in which Moorman dunked herself while playing one of Paik's television-cellos and turns them into a plinth on which monitors play film of Moorman's performance. The piece is a circular argument, a historicising of itself, a sculpture that is a plinth that is a sculpture.

What also becomes clear in these shows is that the evolution of broadcast technology neatly paralleled Paik's evolution as an artist. The sequence of eight monitors in Egg Grows grows ever more upright as it goes along, like one of those charts showing homo sapiens walking erect. The technological evolution of TV monitors allows Paik to do this, but the work also marks an evolution in his own practice. This tendency reaches a spectacular climax in FACT's reconstruction of Laser Cone, a 20ft cloth teepee on to which is projected a rapidly changing geometry of laser shapes. As Norman Ballard, Paik's original collaborator on the project, points out, lasers are unlike normal light in being direct rather than reflected. Their medium is their medium. This two-part show really needs to be seen, even if it reminds you that, while Paik's ideas have passed down to younger media artists, his originality largely has not.

Tate Liverpool (0151 702 7400) and FACT (0151 707 4464) to 13 Mar

Next Week:

Charles Darwent sees Simon Starling rejig the Camden Arts Centre