Of what are artistic fortunes made? Why do some artists’ reputations move up, while others fall? “Beethoven has definitely slumped as Mozart has soared. Is this because we prefer humane elegance to transcendental striving – or is the potent myth-making of Peter Shaffer’s Amadeus to blame? When I was a student 25 years ago, E M Forster was considered among the most profound and influential of 20th-century novelists. Now that homosexuality is no longer much of a battleground, his liberal humanism holds little appeal, and we have become mesmerised by the more aggressive complexities of Kipling instead.”