> Communicating color is extremely difficult! Odd personal anecdote: In first grade art class the teacher held up a piece of art paper and said "This is red".

> Communicating color is extremely difficult! Odd personal anecdote: In first grade art class the teacher held up a piece of art paper and said "This is red". Being the curious student I was, I raised my hand and asked "how do you know?" I was looking for something that would answer both "how do you know I perceive red the same way you do" and also "what defines it to be red". Something about wavelengths and color spectrum etc. would have been a great answer. I was sent to the principal's office as a troublemaker. Never did like art class after that.