Tag Archives: mental image

A certain indeterminacy of color, neither cerise nor taupe nor burnt umber, nor gray either

Fragments from Eric Schwitzgebel’s Why did we think we dreamed in black and white? Prior to the rise of scientific psychology, scholars interested in dreaming generally stated or assumed that dreams have color. For example, Aristotle specifically includes colors among the remnants that sense-impressions may leave in the sense-organs and which thus appear to us […]

A system for detecting an accessible bug

We have described each of the operations on the retinal image in terms of what common factors in a large variety of stimuli cause response and what common factors have no effect. What, then, does a particular fiber in the optic nerve measure? We have considered it to be how much there is in a […]

You are green

“As I recovered at home, colour started slowly creeping back into my life, whispering around corners. This was a very perplexing time, for often I only felt I was seeing a colour but was unable to identify it. I would stare endlessly at trees and lamp-posts, desperate to match the colour I believed was there […]

Escape from the monochrome room

“Imagine a girl called Mary. She is a brilliant neuroscientist and a world expert on colour vision. But because she grew up entirely in a black and white room, she has never actually seen any colours. Many black and white books and TV programmes have taught her all there is to know about colour vision. […]

The ‘dawning’ of an aspect

“I contemplate a face, and then suddenly notice its likeness to another. I see that it has not changed; and yet I see it differently. I call this experience “noticing an aspect…” And I must distinguish between the ‘continuous seeing’ of an aspect and the ‘dawning’ of an aspect… I see two pictures, with the […]

A vision substitution system

Two illustrations of Bach y Rita’s vision substitution system, in 1969. “Four hundred solenoid stimulators are arranged in a twenty x twenty array built into a dental chair. The stimulators, spaced 12 mm apart, have 1 mm diameter “Teflon” tips which vibrate against the skin of the back (Fig. 1). Their on-off activity can be […]

This divine scanner

In How One Sees, Siegfried Zielinski and Franziska Latell trace the genealogy of vision. Quoting the philosopher Abu Nasr Al-Farabi (870-950), the authors write: Optics teach “according to the true circumstances of what is looked at to find the matter, the quantity, form, position and order and the other things which of the things is […]

How to develop a picture from a corpse’s eye

“The morning of November 16, 1880, Wilhelm Friedrich Kühne (1837–1900), a professor of physiology at the University of Heidelberg, dissected the head of an executed murderer in his dark room within minutes of the man’s death. Kühne worked around the contracting muscles in the left eye socket to remove the eye and develop an image […]

Innate species

Although every “acquired species” comes through imagination, Bonaventure creates another category of species, called innate species, that are imprinted directly on the memory. Bonaventure writes, “Memory has to be informed not only from the outside by phantasms but also from the above, by receiving and having in itself simple forms that cannot enter through the […]

Homunculus argument

Original work: Jennifer Garcia,, Derivative work: Pbroks13, and Was a bee. CC BY-SA 2.5-2.0-1.0 One may explain (human) vision by noting that light from the outside world forms an image on the retinas in the eyes and something (or someone) in the brain looks at these images as if they are images on a movie […]