We cannot explain tradition
Any better than a spleen
Can expound upon its mission
Of maintaining our blood clean.
At first I thought "maybe I worded this too strongly". But no, what we have is, surely, a mixture of correct and incorrect explanations of individual parts of traditional systems of morality. But every part interacts with every other, and the system only works as a whole. How would progress in the understanding of the whole look like? The changes that we introduce would lead to better outcomes.
There was a moment in the history of medicine when knowledge about individual parts accumulated to such an extent that life expectancy started to rise, indicating that medicine as a whole started doing more good than harm. I don't think such a change has happened yet in the arena of rational thinking about politics and morals. So I would say that our current explanations of tradition as a whole aren't any more useful, aren't any better, than a complete lack of explanations would have been.
Now a bit on how poetry works:
Everyone understands rhyme, but few understand meter, which is at least as important. It's possible to read and enjoy lots of poetry and song lyrics that contain meter, and yet be unaware of it.
Meter is essentially rhythm. If you're rhyming two lines, they will sound better if you make them conform to the same rhythmic pattern.
By rhythmic pattern I mean the sequence of stressed and unstressed syllables. For example, the word "pattern" contains two syllables: "pa", which is stressed and "ttern", which is unstressed. If we represent stressed syllables by slashes and unstressed ones by dashes, "pattern" will look like this:
Here is the rhythmic pattern of the first line of my quatrain above:
In this poem I rhyme alternate lines within each quatrain, so the first line rhymes with the third one. And they have the same rhythmic pattern.
There's one complication here though. In other quatrains in this same poem the first line is /-/-/-/- while the third one is --/-/-/- or vice versa. Yet that sounds OK. Why? I guess at some level the brain interprets --/-/-/- as a variation on the simpler, more regular /-/-/-/-. So /-/-/-/- becomes the expectation. By the way, the fancy term for /-/-/-/- is trochaic tetrameter. It seems to be OK to put an unstressed syllable where a stressed one is expected, but not vice versa. At least that's been my experience. If you put a stressed syllable where the reader has come to expect an unstressed one, the effect is often unpleasant.
People like both repetition and variety. There is a happy middle somewhere between these two things which a good poet, musician or writer can find, and which the bad ones miss. Of course, the smarter the audience, the less repetition it likes.
One way to insert some variety into a poem is to alternate lines that end in a stressed syllable with lines that end in a unstressed one. I like this effect a lot, so I'm using it in this poem. It makes the writing process harder though because in English the number of two-syllable rhymes (like tradition/mission above) is more limited than the number of one-syllable rhymes like spleen/clean.
Why do people enjoy listening to rhyme and meter? I don't know. Maybe a liking for rhythm prevented our hunter-gatherer ancestors from getting bored on long walks, allowing them to walk further. Think of soldiers' marching songs: they're all heavy on rhythm and have a meter.
But that's a guess. As I was trying to say in my above quatrain, our ability to understand why we are the way we are is limited. The evolutionary and cultural forces that made us were much too complex for us to understand them fully.