What I’m gathering is that “wave” can refer to a behavioral pattern that is substrate independent — it refers to a logical function more than it does an ontological presence

I think that’s a good way of putting it.

As for what counts as a “substrate”, I have no idea! In the old days, the idea of a substance that permeated seemingly-empty space was common. See: https://en.wikipedia.org/wiki/Aether_theories

Nowadays, the idea of aether has been discarded for the most part. But that said, there’s still plenty we don’t understand, like dark matter. There’s no consensus on what dark matter is exactly; there are many competing theories. What we know is that there are observable phenomena that can’t be explained without something that acts (roughly, at least) like matter in terms of its effect on gravity, but doesn’t interact with electromagnetism like normal matter. That “something” is called dark matter, but its fundamental nature is an open question.

Now we’re getting into linguistics with the question of “what is a wave?”

In quantum physics, basically everything is waves, in the sense that the same mathematical formulae used to describe waves are used to describe quantum phenomena. The intuitive human-scale dynamics of waves don’t necessarily apply though.

For example, sound waves can’t propagate through a vacuum, but light waves can. Aside from that, they follow mostly the same rules. You can use the same math the describe interference of sound waves and light waves, for example.

People talk about the “particle/wave duality” of photons because in some ways they behave like waves and in some ways they behave like particles. But both of those words are stretched a little from their everyday plain-english usage, and the precise reality would require years of study to understand.

Plain English wasn’t made to be that precise or objective. That’s why we use math. :)

I’m no expert in quantum physics so take this all with a grain of salt.

The coolest, and often most confusing thing about computer science, information theory, and perhaps reality in general, is how everything becomes more or less equivalent if you boil it down and twist it around a little.

Everything is sorting. Everything is compression. Everything is geometry. Everything is language. Everything is music. Everything is, like, waves, man. *puff*

Or more accurately, everything can be expressed in any of those other things’ terms.

These are not new ideas, but computers have made them provably and demonstrably true in many contexts, and I think that’s super cool.

You mean Emacs?