• Talent/Intelligence

Why it's tempting to postulate an essence: people seem to be good at different things, and for any particular thing, some people are better than others; and since we can't read others' minds, and people aren't always skilled in introspection and explanation, it's not always easy to find out what they know that we don't.

• Aesthetics/"Taste"

Why it's tempting to postulate an essence: people have different "tastes", and it's difficult to argue them into changing their mind about what they like. Plus, people aren't good at introspecting to discover via analysis why it is they like what they like, and are motivated not to do so because they're afraid they won't like it anymore (similar to the way people fear physicists' reduction of rainbows). Plus, shared tastes are a common criterion used to divide people into tribes.

• Music Theory

Why it's tempting to postulate essences: certain periods/styles exhibit empirical regularities not shared by other periods/styles, and cataloging these regularities is felt to be most of what the subject matter consists of. The discipline doesn't have a culture of reductionism, perhaps because irreducible "talent" (see above) is already assumed among those studying it, so there's no need to systematically address the question of how to make music from non-music, or how to invent new styles. Also, people can sense that treating such questions systematically would involve difficult new abstractions, in contrast to the concrete concepts used to do cataloging, and they run away in fear.