"It struck me only recently that nineteenth century painters must have believed that visual truth was defined by photography, however alien to human vision what the camera reproduced often was. A good example of this would have been Eadweard Muybridge’s photographs of horses in motion. Painters decided that Muybridge’s images showed what horses really look like when they run, and in effect copied Muybridge’s photographs in their paintings of horses, even though that is not at all the way we see horses when they run. We really don’t see animals move the way Muybridge shows them moving, or else there would have been no need for the photographs in the first place: Muybridge hit upon his awkward but seemingly authoritative experiments that were really designed to answer such questions as whether all four of a horse’s hooves ever touch the ground at the same time—in other words, phenomena the human eye could not perceive."