[Nicolai P. Zwar]

My default assumption is that our notions of consonance come from certain culturally constructed expectations and habits, and are not intrinsically determined by mathematical or physical properties, but that the mathematical properties of certain intervals can give rise to physiological features which make them more easily recognisable to our perceptual faculties, and that this in turn gives them a much greater chance of becoming important players in any culturally constructed musical language, and hence of sounding “pleasant” to the people steeped in that culture.

That seems to be in any case at least part of it; as I noted higher up, one could argue that actual “dissonance” can be found only in tonal music, because dissonance usually refers to harmonic tension. A single “note” or “chord” is neither consonant nor dissonant, it can become dissonant within context. Any chord, any frequency sound can become “dissonant” in the “right” context.

There is definitely a “learned” component when it comes to listening to music, as you said “culturally constructed expectations and habits”. I just have to look at myself, I remember my “listening history” quite well, from my first encounter with music, to the many composers and types of music I branched out to over the years (and decades). There was music that I could not penetrate when I was younger, like Beethoven’s String Quartets or Bach’s Keyboard works, and now I think they are among the greatest compositions ever, so I have definitely “learned” how to listen to them.

On the other hand, there is also a visceral component, and immediate “gut reaction” to music, that seems to be more “universal”. In fact, it is onto that “visceral” component that over centuries, Western Classical music has built the “learned” architecture for complex compositions, but it is practically impossible to draw the line between a “learned” and an “instinctive” reaction to music, even though no doubt both exist.

It is quite interesting when you look at some studies as to why people listen to music in the first place, and why and how some music affects some people deeply and leaves others cold. In the end, while there are some theories, we don’t even really know. And perhaps that “mystery” is something that can never be fully and truly be “solved”, because what and if music affects us is at least partly highly personal.