‘Tone color’ and ‘word painting’ both refer to sound and sight. Program music attempts to convey imagery in sound. And even in theory we ‘build’ chords, evoking a sense of touch with sound.
Inherent in our discussion of music is a synesthetic vocabulary.
That is to say we are not confusing this vocabulary with actual synesthesia. It does beg many questions though.
So say I listen to Hector Berlioz’s Symphony Fantastique. Would I experience the same thing as someone with synesthesia? Are the images I see from the sound sincere? Were they not artificially induced from the program notes Berlioz wrote?
If that is the case, do these notes, along with the aforementioned vocabulary, play with if not rewire the brain of a non-synesthetic to have a synesthetic experience? The question then comes back to whether that experience is sincerely synesthetic.
Either way, something fascinating happens when music and the other senses converge.