The mechanists have pieced together the sensory and motor organs of animals, like so many parts of a machine, ignoring their real functions of perceiving and acting… But we who still hold that our sense organs serve our perceptions, and our motor organs our actions, see in animals as well not only the mechanical structure, but also the operator, who is built into their organs, as we are into our bodies. We no longer regard animals as mere machines, but as subjects whose essential activity consists of perceiving and acting. We thus unlock the gates that lead to other realms, for all that a subject perceives becomes his perceptual world and all that he does, his effector world. Perceptual and effector worlds together form a closed unit, the Umwelt. These different worlds, which are as manifold as the animals themselves, present to all nature lovers new lands of such wealth and beauty that a walk through them is well worth while, even though they unfold not to the physical but only to the spiritual eye.
(Jakob von Uexküll 1934/1957:6)
Color is the 'place where our brain and the universe meet'.
(Paul Cézanne, as quoted by Maurice Merleau-Ponty (1964:180))
At the beginning and end of Chapter 3 I suggested that the concept of colour as it figures in visual science is inherently double-sided or Janus-faced (Mausfeld et al. 1992:47)-one side