It sounds like you're assuming that they actually have any copyright on this. They don't. It's not identical but see: https://news.ycombinator.com/item?id=30702117 for some similar issue.
And in general, you must be "creative" to have a copyright. You might have a "copyright" on the resulting file, but no court would ever dream of extending that to a claim of copyright on every melody. There is no way that the author was "creative" in any sort of proportion to the amount of material being putatively claimed. Normally one would expect for this to then start a big HN chain arguing the precise definition of "creativity per unit output" that is the threshold, but in addition to the fact you have to get a court to agree to your definition, bear in mind that this is quite literally exponentially little creative effort per output. The author has put in so little effort per output that they haven't even listened to their own "work" once, I'm sure! This is not the normal definition of a "creative work". The usual arguments will be based around a polynomial at most, and frankly usually linear amount of output per "creative input". Especially in light of the fact that the lifespan of a given "creative human being" isn't even "linear" so much as "constant".
Given that this is only a very small amount of effort from being able to claim all combinations of notes ever, it's clear this is not a copyrightable work, excepting perhaps the literal output of the work but no more than that.
(It's also not that much more work to order these things in entropy order, by analyzing songs and deriving some probability for note lengths and intervals, making it so that one could just start generating melodies and actually hit almost every useful melody in an even "smaller" work. Also not copyrightable.)
So, basically, don't learn anything about copyright from this article.
I mean, the game No Man’s Sky procedurally generates 18 quintillion planets but they hold a copyright on all of those planets, don’t they? They certainly haven’t explored all of the planets.
IANAL but I'm pretty sure generating something, even something creative, isn't enough for protection if it isn't novel and distinct. I'd assume none of their planets would be protected since there are 18 quintillion of them and most of them have never actually been rendered - but the process to generate planets of that style might be protectable.
this makes sense to me. If i custom design a planet for a game and unknowingly recreate a fringe planet from no man sky.. it really doesnt feel like copyright.
or if i create a completely different procedural generation method for planets and 99% of my planets differ from no mans sky but there is an identical overlap of some of my fringe planets and theirs, it again does not feel like copyright.
but if i take their method and tweak it a little bit so i also make a game with 18 quintillion planets of a somewhat different variety but am only able to do so because i am copying their methods without their consent.. that feels much more like copyright. even if none of my planets are an identical match to a single one of theirs
Imagine you load the No Man's Sky source code, and you break it all down, and you load the assets in. You certainly have a copyright on all the assets.
You don't generally end up with a copyright on all possible combinations. You may still de facto "own" the copyright if all possible combinations encompass parts of your own creation. For instance, I've been playing XCom 2 lately. It has a character creator. Firaxis can't claim to own all the possible combinations of characters it can create, but they own a substantial portion of the parts. I don't think they could claim they own eyes of a particular color or particular shades of skin, but all the clothing, accessories, tattoos, guns, etc. all individually have copyright, so it's still not like I personally can just crank up the character creator and claim a copyright on some particular one and start using it for whatever commercial purposes I desire.
No Man's Sky, from the looks of it, is in the same boat. They don't necessarily get "a copyright" on everything their algorithms can possibly generate, but at the same time, if someone produces an exact match of any of the 18 quintillion planets they must be using plenty of copyrighted assets along the way. So in practice there may not be a big difference.
Where the difference comes in is when the pieces get to be so fine that they are not themselves copyrightable. To put it in a visual context, the original favicon format was 16x16. Even at full 24-bit color, that's only 2^32 possibly favicons. It's trivial to enumerate them. But you can't copyright a single pixel, and you can't simply claim a copyright on all combinations. The former is a bare fact, and the latter had no creativity ("enumerate all possibilities" is not creative, it's a homework assignment in Comp Sci 201). You can't copyright a single note, it's a bare fact. You can't copyright all enumerated combinations of them. You can copyright the program used to generate them, but that doesn't give you rights to the output.
So, they do and they don't. And the sense in which they do doesn't match the sense in which trying to copyright all possible melodies does.
In the event that you have something like https://www.youtube.com/watch?v=8fZBUsn5RYg , kkrieger, a super-procedurally-generated game that doesn't have any clear textures or geometry in its code, I think you could claim a copyright on what gets manifested, but not on every conceivable thing the algorithm could generate. What gets manifested will be a much more reasonable amount of protection relative to the effort, merely polynomial at most, rather than exponential. Exponential is, you know, really big.
And in general, you must be "creative" to have a copyright. You might have a "copyright" on the resulting file, but no court would ever dream of extending that to a claim of copyright on every melody. There is no way that the author was "creative" in any sort of proportion to the amount of material being putatively claimed. Normally one would expect for this to then start a big HN chain arguing the precise definition of "creativity per unit output" that is the threshold, but in addition to the fact you have to get a court to agree to your definition, bear in mind that this is quite literally exponentially little creative effort per output. The author has put in so little effort per output that they haven't even listened to their own "work" once, I'm sure! This is not the normal definition of a "creative work". The usual arguments will be based around a polynomial at most, and frankly usually linear amount of output per "creative input". Especially in light of the fact that the lifespan of a given "creative human being" isn't even "linear" so much as "constant".
Given that this is only a very small amount of effort from being able to claim all combinations of notes ever, it's clear this is not a copyrightable work, excepting perhaps the literal output of the work but no more than that.
(It's also not that much more work to order these things in entropy order, by analyzing songs and deriving some probability for note lengths and intervals, making it so that one could just start generating melodies and actually hit almost every useful melody in an even "smaller" work. Also not copyrightable.)
So, basically, don't learn anything about copyright from this article.