The association between the composite sense and the mirror comes
directly from the thought of Plotinus, who likens conceptual imagination
to a mirror.^67
The Brethren of Purity clearly articulate this relationship between the
senses and contemplative faculty as an image:
Know that, when the imaginative faculty brings the record of sensed things to the
contemplative faculty, after obtaining it from the faculty of sensation, and after the
sensed things have disappeared and are no longer witnessed directly by the senses,
that record remains in the thoughts of the soul as imagined immaterial images.
Thus the substance of soul is, to this record pictured in it, like prime matter, and it
[the record] is in that [soul] like forms [are in prime matter].^68
They then explain how a man reengages his sensory experiences after
leaving a city he has visited by deploying the analogy of wax from the
Platonic and Aristotelian analogy with the mind.^69
If, after the passage of time, his memories of it reoccur, that contemplation is none
other than the glance of the soul onto its own essence and its imagining an image of
the city. What existences it sees in it are nothing other than the forms of those
existing things that are now imprinted on the substance of its soul in a way similar
to the imprint of a stamp on sealing wax.^70
Similar definitions emerge inThe Book of Optics(Kitab al-Manazir)by
ibn al-Haytham, which offers experimental solutions to the longstanding
conflict between optical theories based on intromission (the idea that light
enters the eye to create the effect of vision) and extramission (the idea that a
ray exits the eye to create the effect of vision). Like ibn Sina, ibn al-
Haytham divides the labor of seeing into distinct physical and psycholo-
gical phases. This distinction solves what was considered the central con-
undrum of intromission theory: how does the eye perpetually receiving
information from all objects and all angles keep so much information
straight?
Ibn al-Haytham develops a model of the visual cone in which only the
central ray of the cone achieves clear sight; all other threads of the cone
remain blurry, as in what we call peripheral vision. Ibn al-Haytham
postulates that to perceive the form of an object beyond any single point
informing the eye, it must move and collect data from multiple points of
each object.
(^67) Warren, 1966 : 278 (4.3.29, 1.4.10). (^68) Walker, 2016 : 129. (^69) Graves, 2018 : 39.
(^70) Walker, 2016 : 129.
The Science of Internalized Vision 125