“ Hering’s original argument: Hering put forward two arguments. First, that mixtures of his opponent colors (‘reddish green’) are inconceivable. … Second, He

“ Hering’s original argument: Hering put forward two arguments. First, that mixtures of his opponent colors (‘reddish green’) are inconceivable. … Second, Hering argued that unique hues are unique insofar as they describe all colors and cannot themselves be described.”