This dissertation consists of two parts. Part I examines three historical attempts at
explaining colour on the basis of Goethe's Farbenlehre. Schopenhauer, Hegel and
Wittgenstein each give successful explanations of some but not all colour phenomena.
As they succeed and fail in the same areas in which more recent subjectivist and
objectivist accounts succeed and fail it must be concluded that the nature of colour does
not allow for reduction to subjective states of mind or to objective physical processes.
Part II examines colour itself: The first three chapters establish internal colour
relations. Colour language and colour blindness re-introduce the human subject whose
importance is most evident in the contemplation of paintings. As paintings cannot only
represent three dimensional objects but can also evoke feelings through mere colour
effects, colour is an important medium for the communication of subjectivity and
The conclusion is twofold. First, we have to strictly differentiate between the
ontology and the epistemology of colour: Colour exists objectively and hence
independently of observers, but internal colour relations are nevertheless determined by
human thought. Secondly, colour is irreducible: although science can explain most of
its aspects the nature of colour itself can only be understood through the irreducible
variety of colour effects.