It is an intelligible or thinkable reality, though not a sensible or perceptible one. The Aristotelian concept of universals similarly builds from sensory evidence of things to concepts about those things to the concept of conceptual things. Red, yellow, and blue things can be seen through the operation of the senses; the ideas of red, yellow, and blue can be conceptualized through abstraction. The further abstraction—the concept of colour—no longer pertains to anything sensory but concerns an extrasensory phenomenon, colour in general, or colour in the abstract. The signification or meaning of a vocal sound (a word or a sentence) is similarly extrasensory but again entirely real.
