Pictures in the book "Mystery of Color Vision and Fundamental Question"

Evolution of color vision with splitting of sensitive lines of cones:

"Red and cyan" instead of "red and green" are a pair of opponent colors:

Continuous-value logical oprations:

Decoding Model:

Color blindness:

The essence of ostensive definition (identical language and different sensations are possible):

The similarity among idealism, logical epericism, and naive materialism: