‘But why do you think Mathilde follows people in the street?’

‘The short answer could be that she collects oddities,’ said Louvenel, fiddling with the creases in his trousers and then with his socks. ‘You could say that these people she preys on are like her fish, she spots them in the street, she chases after them, then she pigeonholes them. But really it’s the opposite. Mathilde’s problem is that she’d be perfectly capable of going and living alone under the sea. Yes, she’s made it her life’s work, she’s a tireless researcher and a distinguished scientist, but all that means very little to her. The real draw is the territory she’s found for herself, underwater. […] But the ocean takes her away from human society, and she realises that. Because she’s also got a big slice of good-heartedness, or generosity if you like, that can’t be satisfied with the underwater life. So at regular intervals she comes back to the surface, and gives in to the other temptation, the one that draws her to people, I mean people, not humanity. So she makes her peace with all the millions of little steps people take as they tread the Earth’s crust. She takes everything to extremes, and every scrap of behaviour she can capture, wherever it is, seems a miracle to her. She memorises it all, she notes it all, she “Mathildises” it all. And she picks up lovers along the way, because she’s quite capable of love. And then when she’s tired of all that, when she thinks she has loved her fellow creatures enough, she goes diving again. That’s why she follows strangers in the street. To get a kick out of the flicker of someone’s eyelids or the twist of an elbow, before she goes off again to defy the immensity of the universe on her own.’

(The Chalk Circle Man)