If any of you are aware of sacred geometry, you'll know that the notes we tune to and play were discovered (to be 'good') according to precise vibrational/mathematical relationships, which are definitive and objective.
A great deal of histories most eminent art and architecture has been produced by incorporating these same principles, and has been prolific enough to be deemed good.
I could liken the way those images and buildings extended from their focal/starting points using interrelated geometric patterns to the way a piece of music extends rhythmically and melodically.
I'd like to contend that if our musical notes are considered correct/good because of their relationships and values - and we know they are - that same element of perfection should, and does, extend to our scales.
If it extends to our scales, can it not extend to the potential melodies within those scales? If mathematical relevance can be found in our melodies, why not also our rhythms?
If you see music as mathematical, it becomes objective.
Nobody is going to sit and work out equations to write a piece of music that is universally good. But everybody tries to write the 'correct' note (to their perception), and on the 'right' beat, for the 'right' duration, that follows the one before it. Funny that this is no more apparent than on a four-string.
But I do think that music can be universally good - I'll wrap it up with the following analogy.
In sacred geometry there is a 'golden ratio', which can be represented as the length and width of a rectangle.
An experiment was done where they showed people a series of shapes progressing from a square to a very long rectangle, and asked them to choose the one they liked.
The results showed an exponential curve toward the rectangle representing the golden ratio in its length and width.
So, some people preferred other shapes, for other reasons, sure. But there was an incredibly convincing consensus of what was good, in an objective manner.
If it applies to our eyes, why not our ears?
PS - this is beautiful