In Steve Reich's phase phase, the process is the product.
When something happens, it's new information to our brains. But when it happens 100 times exactly the same, it's redundant. Our brains stop seeing the individual bits and are invited to see the gradual transformation of the bits.
All music has this to greater or lesser extents. Things happen; things change; things stay the same. But what changes and what stays the same? How does it change? How much?
Minimalist composition strips away all of the distractions in more traditional composition and focuses on this process, allowing a few elements to change gradually over long periods of time.
It lays its structure bare; the structure is a process.
But it's so stark that the flaws stand out like wrong notes in a Mozart string quartet. There's nowhere to hide. Like a building, if it stands it works.
But too many contemporary compositions are covered in neon glitter paint, slathered over cheap, plaster-of-paris compositions with no foundation and flimsy structure. We didn't learn our lessons from the minimalists.
I thought of this post the other day. I got home from work, exhausted, lying on my bed, and was too tired to move but could just barely reach my guitar with one hand. The original minimalists stripped it down even further. You don't have to be a minimalist to write some minimalist pieces. It'd probably do you some good, teach you something about information and patterns.
Here's a collaborative Spotify List that I started. Feel free to contribute.