Abstract

Studying colour vision across various species suggests that different species perceive different colours (the Disunity Hypothesis). It is plausible that all species’ color visual systems are, at least in principle, equally correct/veridical regarding colour (Ecumenicism). Assuming that colours are mind-independent features of material objects (Objectivism), it follows that objects simultaneously have different colours for different species (Pluralism). But are all these colours compatible with one another? Some have argued that they are on grounds that, while comparisons between colours are possible within a given species’ colour space, they are not possible across the colour spaces of different species. Since colours from different spaces are not comparable, they cannot be incompatible. Hence, a given object can have a colour from as many colour spaces as needed to explain interspecies variations in colour perception. I argue that this reasoning is flawed in two ways. First, colour spaces that are non-comparable in pure or abstract reasoning, may nonetheless be comparable in applied contexts. Second, in our applied context – our world – evidence suggests that incompatibilities between colours from different species’ spaces are extremely likely when Colour Objectivism is presumed. But then the Pluralist solution to interspecies variation seems unavailable to the colour objectivist.