An Account of some Observations made by a young Gentleman, who was born blind …"

6  Locke comes at the beginning not so much because he offered the eighteenth century a powerful theory of visual perception, though he did this too, as because, in the course of stating his theory in An Essay Concerning Human Understanding (1690), he framed in a particularly gripping way the issue of how we achieve a perception of the three-dimensional world from the two-dimensional array of stimulations on the retina. The form in which he first established the issue was: on what basis do …