Lightness and Brightness and Other Confusions

ence derives its origin from multiple sources that are external as well as internal.
Our visual experience of the world does not emanate from a series of static
retinal images. Our vision has access to a dynamic flow of continuously varying
retinal information interplaying with complex information from all other
senses, about spatial colour and light relations, about spatial movements,
about our present position in space. In accordance with Merleau-Ponty’s
‘human world’ JAMES J. GIBSON 22 describes an ecological approach to perception;
there is a tight perceptual attunement between human beings and their
environment. The perceptual relationship between the outer world and the
human inner world is natural and without hindrance. The perceptual systems
have developed for millions of years interplaying with the surrounding world
(Gibson 1979).
ALVA NOË 23 referring to Gibson, comments that “the perceptual world (the
environment) – – is not a separate place or world; it is the world thought of
from our standpoint (or any animal’s standpoint).” (Noë 2004, p 156). It is
the world “for us” 24 , the special human perceptual niche, in ecological balance
with the human environment. Gibson and Noë regard man as ecologically
integrated in a world, where appearances are genuine features of the
environment; hence colour and light, in Gibson’s ecological sense, are natural
but non-physical (Noë 2004, p 155). We know nothing more except that they
exist and give us impressions and order in time and space. The Swedish perceptual
colour notation system Natural Colour System (NCS) is natural in
Gibson’s sense.
One world, several aspects
The ultimate aim of human perception and cognition is to achieve and maintain
a constant and coherent world. Gibson calls attention to the fact that the
perceptive registration process is successive, but it is nevertheless experienced
as if it were simultaneous. (Gibson 1958, p 184).
Human perception is often described as structuring information from the
outer world. Attention is not so often called to the fact that one of the most
basic functions of the perception process is to select and discard information
in order to make it more comprehensible. The flow of potential information
in the outer world is immense. The human perceptual niche is narrow and
22
American psychologist, 1904–1979
23 American philosopher, 1964–
24
For us refers to Immanuel Kant, who makes a distinction between the-thing-in-itself
(das Ding an Sich; the world beyond the phenomena) and the-thing-for-us (das Ding
für uns; the world as experienced through our knowledge. (Kant (2004, pp 325–327).
22