Yeah, I think a good discussion on music theory is starting from first principles, explaining Pythagorean tuning, then explaining 5-limit just intonation, the explaining we compromised on 12-tone equal temperament because it made tuning and changing keys a lot simpler, at the expenses of some notes being slightly out of tune (e.g. the minor and major thirds deviate by about 15 cents from their 5-limit just intonated “ideal” tunings).

You're saying its not possible to tune a piano to an arbitrary set of 88 pitches?