In my last post about Diogenes the question was raised: is stealing, embalming and displaying a dead tramp art? Tilda Swinton in a glass case, a video of David Beckham asleep, sound installation, performance art, embalmed sharks, embroidered tents and unmade beds, modern artists have repeatedly challenged what it is that can be regarded as art. What counts as art? How do we judge its value? Who is in a position to tell us what is good? These are among the vexed questions of aesthetics.