While 3/2 is assoclated with power, 5/4 is more expressive of sentiment and emotion. To my ear, these qualities of the primes show up to some extent in combined intervals; for example, the included interval 5/3 (a "major sixth") seems to convey some "fiveness" and some "threeness." This would imply that the character of any just interval includes expression of the prime factors that make it up. Of course, all this is highly subjective.

In early times the interval 5/4 was considered discordant; its acceptance as consonant came centuries after 3/2 gained popularity. Then it became firmly established as an essential component of traditional triadic harmony.

http://www.redshift.com/~dcanright/harmser/

Power versus a more nuanced expression of differing feelings. Sort of like forcing people in line versus actually using reason and communicating their differences. Originally the 5/4 sounded discordant but as the ears spent time hearing it became 'musical'. With time a much larger and discordant scale could become acceptable. Would such routinely listened to by an entire society influence the actions in the same direction?

justonic and long explanation of just intonation

http://www.justonic.com/demos.html
Do I really care? Not sure.


These commas exist only outside the confines of the twelve notes tones of equal temperament. In fact, tempered tunings were developed over the past four hundred years precisely to avoid the commas that are heard whenever music with moderately complex harmonies is played in just intonation. I have discovered that incorporating the commas into the harmonic fabric of my music frees it from the need for tempered tunings and opens up a new approach to tonality.-Michael Harrison (as opposed to justonic)

Throughout the history of Western classical music there has been a gradual evolution from the use of relatively wide and consonant intervals to increasingly narrow and more dissonant sounding intervals. For example, organum, early two-part music that developed from the 9th to 12th centuries, used the consonant open sounding intervals of perfect fourths, fifths and octaves. In the 15th and 16th centuries, the relatively dissonant intervals of seconds, thirds, and sevenths were interwoven into the polyphonic fabric of the music, which was still organized contrapuntally as opposed to tonally. At the beginning of the 18th century, music began to be formally organized around tonal centers. As major, minor, and other key relationships developed, it became essential to create a tuning system that permitted moving easily between different key centers. In the 19th century, the evolution of even more complex chromaticism resulted in stretching tonal harmony to its limits. In the 20th century, Schoenberg’s concept of “emancipation of dissonance” led to the free use of any interval combination in equal temperament. I propose that this evolution is still in progress, and that its next stage is the “emancipation of the comma.”

etc...