ABSTRACT
Visual perception has received the attention of scientists and ‘natural philosophers’ (as well as doctors) for longer than any other psychological topic except memory. The ‘Moon illusion’ (the larger appearance of the moon, and in fact the sun, when near the horizon) was known in ancient times, discussed in the Philosophical Transactions of the Royal Society in the late seventeenth century, and has frustratingly resisted satisfactory explanation to the present day (H.E. Ross and C. Plug, 2002). With the advent of lenses and optical instruments incorporating them, much attention was paid to optics, the lens-character of the cornea being recognised from early on. Optics and the anatomy of the eye were thus one of the earliest fields of natural philosophical study and experimentation, these frequently verging on being Psychological. How far perception was learned or innate was discussed by John Locke and his Ulster associate W. Molyneux; whether a congenitally blind person suddenly given sight would be able to identify shapes becoming known as ‘Molyneux’s Question’. A little later the philosopher G. Berkeley (1709) addressed the function of binocularity.
