Penelope Lively said this quote

“ I have a print - you can buy them at the Victoria and Albert Museum - of a photograph of the village street of Thetford, taken in 1868, in which William Smith is not. The street is empty. There is a grocer's shop and a blacksmith's and a stationary cart and a great spreading tree, but not a single human figure. In fact William Smith - or someone, or several people, dogs too, geese, a man on a horse - passed beneath the tree, went into the grocer's shop, loitered for a moment talking to a friend while the photograph was taken but he is invisible, all of them are invisible. The exposure of the photograph - sixty minutes - was so long that William Smith and everyone else passed through it and away leaving no trace. Not even so much of a mark as those primordial worms that passed through the Cambrian mud of northern Scotland and left the empty tube of their passage in the rock.I like that. I like that very much. A neat image for the relation of man to the physical world. Gone, passed through and away. ”