is visible, then sight will sense of this and similar bodies their extension in length
and breadth alone; it will not sense the solidity of bodies of this description.
Assume, however, that sight perceives a body that is surrounded by intersecting
surfaces of which the one facing the eye is inclined to the frontal direction,
whatever thefigure of that surface; assume, further, that the surface intersects
another of the body’s surfaces in such a way that the eye perceives the intersection
of the two surfaces along with perceiving them together; then, because of that
intersection, sight will perceive the bending of the body’s surface in the direction of
depth. And if it perceives the bending of the body’s surface, then it will perceive the
body’s extension in that depth. But it perceives of the inclined surface the extension
of that body in length and breadth. And by perceiving the body’s extension in
length, breadth and depth, it will perceive the body’s solidity. Therefore sight will
perceive the solidity of bodies situated in this manner with respect to the eye.^73
Besides recognizing the necessity of‘unconscious inferences’such as compar-
ison and memory for sensation to be transformed by the brain into conscious
perception, ibn al-Haytham noted thecrucial importance of eye movement
for observing the visible world. The problem of three-dimensional depiction
was also discussed by Isma’il al-Razzaz al-Jazari (1136–1206) inThe Book of
Ingenious Devices,written in Diyarbakir under Artukid rule:“One realizes that
there is obscurity in the representations of solid bodies, but in the imagination
one canfit one thing to another, view it fromanother,dissectit,andthus
assemble it step by step.”^74 Necipoğlu notes that such insights contrast with
the“reduction of the beholder to an immobile and disembodied eye in
Renaissance single-point perspective, constituting a human subject that is
hardly‘humanist.’”^75 It would seem that the vaunted singular gaze enacted
through perspectivalism does less to give man a Godly overview of the world
than to reduce Man and God alike under the aegis of Humanism.
The recognition of proportions as a phenomenon embodied in multiple
media, both mathematical and not, engages a different relationship
between human and divine from that dominating perspectivalism.
Rather than limiting God through the metaphor of man, in control from
one place, it expands man through the metaphor of God, existent in all
places. Thus Rumi explains:
In form, you are the microcosm
While inwardly, you are the macrocosm.^76
A geometric counterpart to this emerges in ibn al-Haytham’s solution for
representing three dimensions on two dimensions–the problem that
(^73) Sabra, 1989 : 169. (^74) Necipoğlu, 1995 : 152. (^75) Necipoğlu, 2015 : 34. (^76) Rumi, 2017 : 34.
Isometric Geometry in Islamic Perceptual Culture 293