Logic and colour in cognition, logic and philosophy

Dany Jaspers

pp. 249-271

in: Marcos Silva (ed), How colours matter to philosophy, Berlin, Springer, 2017

Abstract

Colour has been on the minds of philosophers, logicians and linguists for a very long time: its connection with logic; the relation between percepts and concepts; the influence of colour language on colour thought, and the question whether colour is in the world or purely mental. The present contribution starts from the age-old observation that the four logical opposition relations (contradiction, (sub)contrariety, entailment) as embodied in the square of opposition and extensions thereof such as the Blanché hexagon are not particularly choosy about the actual conceptual content of the lexical fields they organize. They generalize over modal operators, propositional operators, predicate calculus operators, tense operators, etc. Why would that be? In the first place, it must mean that the relations are located at a level of generality which has no regard for the concrete conceptual differences between those fields, latching on to some very general substrate. Actually, taking that idea further, I have argued (Jaspers, Logica Universalis 6: 227–248, 2012) that the level of abstraction away from concrete incarnations in the vertices of the hexagon even needs to break out of the conceptual realm into that of colour percepts, where a homologous patterning among primary and secondary colour percepts obtains.