First a photo of Hugh Grant - Hugh to his friends. Then, an aquatic mammal found in the Tropics, a manatee. Thirdly, Leonardo's archetypal image of the human body is an extra clue and final flourish. Hugh-Manatee. Hu-manity. Geddit? Doug Fishbone's refined juxtaposition of conceptual art and daft humour here creates a mental hall of mirrors in which ironic images reflect onto each other repeating into the distance. Fishbone's downbeat view of the human condition, evidenced in Hugh Grant's moment-of-disgrace mug shot, is suitably reinforced by the lugubrious expression on the face of the anthropomorphic manatee, yet both are trounced by one of the most familiar images of man's perfection. All of human life is here, to quote Anthony Burgess, in this work of art - mankind at his lowest point and highest sophistication.

Doug Fishbone is one of the cleverest and funniest artists I know. Born in 1969, he belongs to a wave of conceptualists who use humour in their work, including New York based Italian Maurizio Cattelan, the British David Shrigley (Turner Prize nominee this year), Gavin Turk and genial Swiss resident Olaf Breuning. Not so long ago, Conceptual art was the dullest of modern isms. Grainy black and white photographs of housing estates glued onto graph paper, if you were lucky. But in the last decade what was once the unsexiest art movement has become the most ebullient, as artists played with pattern and colour (Hirst), turned typologies into toy ranges (Takashi Murakami), and explored philosophy through humour (Doug Fishbone).

Fishbone's work takes the form of performances, photographs, and films. He first attracted attention - as anyone surely would - by building an enormous pile of bananas in Trafalgar Square, a tropical take on the minimalist triangle (compare with IM Pei's addition to the Louvre). Over the last decade, he's developed a wonderfully deconstructive take on the public lecture, in which he explains with deadpan clarity how difficult it is to know anything for certain in a PowerPoint presentation illustrated with in-appropriate(d) images he has found on the internet. In 2010, he made a whole feature film, "Elmina", which was given a prestigious four month showing at the Tate Britain. In this extraordinary project Fishbone starred as the central character in a Ghanaian movie, inserting himself as a white man in the normally all-black film genre of the commercial African film business.

"Humanity" belongs to Fishbone's body of work with language. The relationship between word and image has been an important subject for artists since Surrealism - from Marcel Duchamp and Magritte to Bruce Naumann and Janis Kounellis. Here Fishbone continues this tradition, appropriating the age-old form of the Rebus, an allusional device that uses pictures to represent words or parts of words. Rebuses were popular in the middle ages, often used on heraldic signs, where for instance, a picture of three salmon fish indicated the owner was called Mr Salmon. But Fishbone moves the Rebus up a few levels from surnames to philosophy, presenting us, tongue-in-cheek, with an eternal paradox of the human condition. .