Biology Reference
In-Depth Information
that test stimulation of rods and cones initiates the same achromatic
colour. Since the subject cannot discriminate between the achromatic
colours obtained under photopic and scotopic conditions, it follows
from the maxim of Mach that the underlying material events are
the same. Hence, the researcher may be misled into neglecting the
important retinal differences involved.
Of course, the finding that the rod and cone receptor systems
may give rise to the same achromatic colour sensation was also a
major challenge for the Young-Helmholtz trichromatic colour theory.
Here, the white sensation was assumed to result from an equal
stimulation of the three primary cone receptor systems, while the
rod system did not have
any
significant role to play (see Helmholtz,
1867
; von Kries,
1911
).
These serious shortcomings of the Hering and Young-Helmholtz
colour theories pointed to the need for a more comprehensive theory
of colour vision where all the three major traditions were incorpo-
rated (i.e. the Newton, Schultze and Goethe traditions). This lead
was followed by several research workers in the early 1900s. The
most detailed and comprehensive theories were provided by Armin
Tschermak (
1902
,
1929
) and George Elias Müller (
1896
,
1897
,
1923
,
1930
), both rooted in the Goethe tradition.
