XXIV.—On the Law of Visible Position in Single and Binocular Vision, and on the representation of Solid Figures by the union of dissimilar Plane Pictures on the Retina

Abstract

In the course of an examination of Bishop Berkeley's “New Theory of Vision,” the foundation of the Ideal Philosophy, I have found it necessary to repeat many old experiments, and to make many new ones, in reference to the functions of the eye as an optical instrument. I had imagined that many points in the physiology of vision were irrevocably fixed, and placed beyond the reach of controversy; but though this supposition may still be true in the estimation of that very limited class of philosophers who have really studied the subject, yet it is mortifying to find that the laws of vision, as established by experiment and observation, are as little understood as they were in the days of Locke and Berkeley. Metaphysicians and physiologists have combined their efforts in substituting unfounded speculation for physical truth; and even substantial discoveries have been prematurely placed in opposition to opinions of which they are the necessary result.

Ocular Equivocation: The Rivalry Between Wheatstone and Brewster

“…The experiment was repeated by several German vision scientists whose observations differed from Wheatstone’s [15]. Brewster [2] also took issue with Wheatstone’s observations and wrote: “The phenomenon described by Mr. Wheatstone is an illusion, arising from actual disappearance of one or more parts, or even of the whole of one of the lines” [2] (p. 358). However, the disputes were generally about the depth seen in the display rather than the rivalry it induced.…”

“…Descriptions of this phenomenon have a long history [1], and it is now called binocular rivalry. Brewster [2] referred to it thus: “The ocular equivocation , as it may be called, which is produced by the capricious disappearance and reappearance of images formed on nearly corresponding points of each eye, is placed beyond a doubt by Mr Wheatstone’s own experiments” (p. 359). That is, binocular contour rivalry could be studied more systematically with the aid of a stereoscope, the device displayed to the public by Wheatstone in 1838 [3,4].…”

“…Brewster’s initial reception of the stereoscope when he saw it at the Newcastle meeting was very positive: “it is one of the most valuable optical papers which has been presented to the Section” [13]. By 1844, his views had changed and he stated that “these extraordinary results are obviously subversive of the established laws of vision, but especially of the law of visible direction; and if they are true, they must arise from a sudden change in the properties of the humours, or in the functions of the retina” [2] (p. 357). This conclusion applied both to stereoscopic vision and binocular rivalry.…”

Early studies of binocular and stereoscopic vision1

“…Duboscq took out a patent for his instrument in 1852; it was a slightly modified form of Lowdon's model, with a ground glass endplate so that both printed and transparent stereophotographs could be observed. Brewster (1844a) interpreted stereoscopic phenomena in terms of visual direction: depth was seen at the location of intersection of lines of direction from each eye (see Ono & Wade, 2012). Brewster (1830) initially presented his theory in a long encyclopedia essay on optics; his theory was virtually unchanged by Wheatstone's instrument and by the observations he obtained with it.…”

“…Among the theoretical issues raised by stereoscopic depth perception and fusion of binocularly disparate images was the extent to which stereoscopic vision was a consequence of eye movements (Ono, Lillakas, & Wade, 2007). Brücke (1841), Prévost (1843), Brewster (1844a), Towne (1869), and LeConte (1881, 1897) proposed eye movement interpretations, despite Wheatstone's description of stereoscopic depth with paired disparate afterimages. According to Brücke, the variations in convergence with successive fixations built up the impression of depth and singleness.…”