For a very extended, and musically informed discussion of your question, I would strongly recommend Roger Scruton's book The Aesthetics of Music . He develops a sophisticated account of the way that we use our imaginations to experience the notes as moving in dance-like ways.

Even if the chords are not presented in the context of a music piece, they are heard in the (more backgrounded) context of music one has heard. Our associations with those pieces of music prime us to hear major versus minor chords in particular ways. There is also a physical reason for finding major chords to be more settled or stable than minor chords: the wavelengths of a major third match the overtones of the root of a chord more closely than do the wavelengths of a minor third . When we hear a C, for example, it is already producing secondary wavelengths that are those of an E (at a higher octave); the addition of a nearby E thus seems to fit in without added strain.