I read in The New Yorker about the artist, Thomas Thwaites, who got a Wellcome Trust grant to learn how to be a goat, and his fellow-traveller who at the same time was learning badger. This was in England. It would be poignant anywhere, once you get into the nitty-gritty of prosthetic goat legs and a goat digestive system, or when the badger sett is riddled with worms after heavy rain. You have to take radical measures to get away from the ravages, the absurdity, of human life.

Thomas Thwaites spent time with goats, practised with his prosthetic legs, read Heidegger, learned to react to his surroundings in a goatlike way. He would have achieved goathood, he thought, when he could see a word without reading it (I'd like to try that), or look at a chair without thinking about sitting on it, or, more important, look at a goat and think of it as another person, like him.

David Garnett's Lady into Fox and A Man in the Zoo from 1922 and 1924, Bloomsbury, explored similar preoccupations, from the point of view of the human trying to hang on to his humanness. David Garnett makes much slower and sadder, fraught progress towards foxhood. One day Mr Tebrick looks round and sees that Mrs Tebrick has turned into a vixen, just like that, complete, no Heidegger, no prosthetics, only suspension of disbelief. He remains in love with his vixen, with his Sylvia, at first he dresses her and plays cards with her, later he's horrified when she kills and devours a rabbit, and jealous when she produces cubs. She has prostituted herself with a fox. How is he going to deal with that? It is only near the end of the tale that he finds his way past his horror of, guilt at, desire for, the bestial.

At that moment all human customs and institutions seemed to him nothing but folly, 'for said he, 'I would exchange all my life as a man for my happiness now, and even now I retain almost all of the ridiculous conceptions of a man. The beasts are happier and I will deserve that happiness as best I can.

David Garnett, known as Bunny, was calming a private mind here. Men sin because they cannot be animals, he concludes. There is always something to overcome, even in Bloomsbury. His man in a zoo, labelled and on show, is another species, mauled by an orang-utan, befriended by a caracal. Tilda Swinton on show in the Serpentine, asleep, is somehow comparable. A zoo, a gallery, an audience.

David Garnett is labouring compared with Thomas Thwaites, who is, according to the subtitle of the book he wrote about being a goat, on holiday from being human. The 21st century manifests a refreshing directness in the face of lunacy. After talking to a shaman about animism and totemism, he concludes

Really, to want to become a goat is pretty standard. In fact, historically speaking it's almost odder to not want to become a goat.