Some philosophical theories of the nature of colour aim to respect a ‘common sense’ conception of colour: aligning with the common sense conception is supposed to speak in favour of a theory and conflicting with it is supposed to speak against a theory. This chapter argues that the idea of a ‘common sense’ conception of colour that philosophers of colour have relied upon is overly simplistic. By drawing on experimental and historical evidence, it demonstrates how conceptions of colour vary along several dimensions and how even supposedly ‘core’ components of the contemporary ‘common sense’ conception of colour are less stable than previously thought.