Defacing and "improving" Goya etchings, overpainting Adolf Hitler’s watercolours, creating horrible caricatures to order, Jake and Dinos Chapman have been amusing, provoking, annoying and impressing audiences for almost a quarter-century. This week, a major survey of their work opens at the Serpentine Gallery. Whether making sexualised child mannequins or fake African artifacts and monstrous tableau melding the holocaust, aliens and McDonalds, the sculptors, painters and occasional film-makers realise that shock is a platitude, and art is always impotent in the face of genuine disaster. They also know that you can’t be an adolescent all your life – even if the assumption of adult maturity is nothing but a myth. Theirs is an art without illusions, as scabrous and nihilistic as it is highly crafted, and they like to bite the hands that feed them – and anyone who deigns to attack them.