Ah, I was worried about that, thanks for the feedback.
I don't know that much about any kind of music, but to the extent that I do know anything I'm much more knowledgeable about jazz than "classical". This is a common failure mode, I think: underestimating the complexity of things you're unfamiliar with compared to those you know better. (It also doesn't help that I learned about jazz into the context of playing it, while I learned about "classical" in the context of learning rule-oriented music theory).
This might completely invalidate my point, then, but I think jazz can at least come close to "classical"'s range of possibilities. Granted, that might be only because of the vast range of free jazz-y stuff that's unlikely to ever become widely popular. If the point does still stand (since, after all, jazz has existed for significantly less time), it is only in a weakened form.
Also, I'm inclined to believe what you're saying about "no musical tradition in the world" ever being as wide-ranging as "classical" music, but it is a pretty substantial claim. Do you mind elaborating on why you think that's so? I'm honestly mostly asking out of personal interest, not doubt; I want to learn more about this.
Yeah, whether the lack of popularity of jazz and classical music is caused by their slowdown or their slowdown is caused by their lack of popularity is one of those tricky questions. There's definitely causation going both ways, but it's really hard to tell which part has more impact, or which one changed first to start off the decline (and if they're both driving each other now, does it even matter which one started things off?). If I had to guess, I'd say that the rise of rock, pop, and (slightly later) hip-hop music gave people new musical options, and this led to the decline in popularity of jazz and classical because, for social reasons, their new competitors were more appealing to most people. This would then cause talented musicians to be attracted to the newer genres, making the older ones worse and less popular, and kicking off that whole vicious cycle. I'm completely speculating here, though; music history is not my forte.
The example of a single band like AC/DC is interesting, and them running out of good music is quite plausible, but other plausible explanations exist too. It would make just as much sense to say that the band members and their relationships changed with time, and since most ways in which a band can exist do not lead to the highest quality music, these changes made them worse. This would explain their declining quality just as well as your hypothesis, and it's hard to tell which is true.
It is certainly true that each song is unique, and once made, that point in song-space will no longer be fresh for the rest of time. The question is whether or not the space of good songs is so large that we don't care about specific points; if it is, your concern is unfounded. I'm not really sure what the truth is here, but I'm leaning toward the space being quite large. Music has a lot of different knobs to turn to make songs original (even while staying within the same genre), and I think you'd need more convincing evidence than "these genres' good output is reducing along with their popularity" to conclude that we've made all the good stuff already.
A bit of supporting evidence for this: classical music can probably be reasonably considered to be a more constrained genre than jazz, with less options for songs because of its stricter style, and therefore a smaller total number of "substantial works". It has existed for hundreds of years longer than jazz music has, so it would be very odd for both genres to be running out of good ideas at the same time, because, based on its longevity, you'd expect jazz music to last much longer than a few decades. Granted, those few decades were in the 20th century only, when much more music was being created than in previous centuries, but the point still stands, if a bit weaker than it could have been. This seems to imply that it's not actually running out of ideas that's causing the decline in substantial new work, if I'm understanding it right. As to what it actually is, though, I don't feel qualified to say.
In the specific cases of jazz and classical music, it seems like a slowdown in creation of original properties could be pretty plausibly explained by those types of music not being very popular anymore (why that is so is a more complicated question), and so not attracting as many of the talented musical minds of the most recent generations. The people who were going into jazz and classical music 50 years ago could be going into rap and electronica now, and it would look pretty much like our world, I think.
I'm not sure if this is actually true, as I know very little about the general state of the music world and how it works, but it seems like a reasonably possible explanation at first, and certainly comes to mind before "we ran out of jazz". Another possibility is that the music industry has changed greatly over the last few decades, and what qualifies as a "meaningful addition" to a genre is less clear than it ever was, as genres splinter and people's musical tastes are given the option to diverge. I much prefer Snarky Puppy's "Shofukan" to, say, "Take the A Train", but there's no way it could reach the same level of cultural saturation because people have so many other choices now (it's not just listening to the one or two jazz stations on your local radio or going to live music if you have a chance, it's Spotify, Soundcloud, YouTube, and probably more).
I float both of these as just ideas; I haven't thought very hard about either of them, but at first glance, at least, they both seem more plausible than "we have made all of the good jazz and classical music already". Yes, such a theoretical limit exists, but music is so incredibly complicated that it's really unlikely we've hit it yet. It seems more reasonable to think this slowdown is due to something else, unless there's good evidence that the limit specifically is the cause.
I could very well be wrong, though. I'm not very confident about any of this because it's a tricky topic.
It can be worthwile to figure out specifically how something that goes wrong, actually does go wrong. In the interest of helping with that, I'll try to add something to all the other criticisms that people have already made here.
The author actually makes a lot of mostly plausible arguments; they're not all accurate or useful (in particular, a lot seem to be in the form of "here's a reason why AI might not be a risk, with no thought going into how likely it is," which is only marginally helpful), but they're understandable, at least. What's especially concerning, though, is that they also invoke the absurdity heuristic, and actually seem to think it's the most important part of their argument. They spend more time on "this idea is silly and is connected to other ideas that are silly" than any one of those other "plausible" arguments, which is really bad practice. To some extent this is understandable, because it was a talk and therefore supposed to be somewhat entertaining, and pointing and laughing at weird ideas is certainly entertaining, but they went too far, I think.
Some more standard advice would be to make some kind of public commitment to it, so there's somebody else to hold you accountable. This could be kind of difficult when it's something as unimportant as a video game, as that might make you look pretty weird (depending on your friends and your relationships with them), but you could do it very casually; even just mentioning the task in passing in a conversation would probably help. I also find that making a "public" commitment helps even when it's not actually public; just consciously focusing on the subject and committing to hold yourself accountable for doing it at a certain time can be surprisingly effective (I like to say it out loud, as this seems to help, but I talk to myself a lot anyway so it might just be a personal thing). I can't really vouch for this method's effectiveness, though; I've never really tried to permanently solve a recurring problem like the one you describe with it, I've only used it as a band-aid to get past the "ugh field" a few times. It may lose its effectiveness with repetition, if it even ever works at all for you. A last possibility in this category, depending on how serious you are about this, would be to try something like Beeminder that would ideally give you the motivation to push past the "ugh field" and get used to doing what you need to do. Since I don't yet know how to embed links in words, here it is: https://www.beeminder.com/
For something more fun, if probably less practical, you could try to drug yourself into forming a habit. You've probably heard of people trying to use reinforcement learning on themselves, basically -- allowing themselves to eat candy (or some other kind of reward) when they do the target activity. I'm really doubtful that this is actually useful for most people (though I haven't looked much into it -- I just have a vague, bad feeling about it; it's probably worth investigating). Luckily, though, you can try something better: using nicotine to turbo-boost your habit formation. This is probably wildly irresponsible, and I don't really recommend it, but it's worth hearing about, at least. Of course, you'll need to take into account the extra cost of getting nicotine gum (or patches -- just don't smoke, that's definitely not worth it), as well as whatever psychological costs the chance of getting addicted to the drug might entail. I'm not going to go into specifics, but instead just show you to the source of the idea (which I just discovered fairly recently, which is probably a large part of the reason I'm bringing up nicotine at all): http://www.gwern.net/Nicotine#habit-formation
I'm not sure about the level of rigor you're looking for; whether this is supposed to be a fun, short assignment, or something less accessible. This doesn't really go into any mathematics, but shows the interesting and even entertaining side of game theory pretty well:
There're also Douglas Hofstadter's writings on game theory, which, like pretty much everything of his, are a joy to read (for me, at least). I wouldn't quite say he uses game theory to "explain something," but whatever he does do achieves a similar goal. Unfortunately, the only PDF I could find (not that I looked very hard) is very poorly formatted; I recommend searching it for "Dilemmas for Superrational Thinkers" or going for the Post Scriptum starting on page 31, as those are both particularly interesting parts (in different ways).
I hope one of these was helpful.
Right, that's a good point you're making about most points in song-space being worthless, and it maybe even shows that the multidimensional-space way of looking at things isn't really appropriate in this situation. Since I can't think of anything better, though, we might as well just keep talking about a "sparsely populated" space.
I think that distinction comes to core of the problem here: we're talking about a hugely vast space, where a hugely vast proportion of points in it are inconsequential. There's a battle going on between those intuitions of "hugeness;" for me, the space wins out, for you, the sparseness. It's probably not possible to reconcile these intuitions easily, as they're not immediately based on anything concrete. As unfortunate as the phrase is, I guess we'll just have to agree to disagree (unless I'm totally wrong here, which is a possibility). For what it's worth, I'm less confident now in my opinion that music genres like "classical" and jazz aren't close to being filled up.
You're making a bit of a different point in this comment, though, which I think it's important to clarify. It seems to me to be far more likely that a specific genre that has existed for decades or centuries is filling up, than that music as a whole is anywhere close to completion. The two are very different claims.
You mention rap and electronica as being some of the "final genres" to be substantially completed, but think of where they came from, and why they are the most recent genres. Rap (or hip-hop, not really sure which is the more accurate term for what I'm talking about) came out of a period of profound social change, while electronica is only possible due to technological advances in the last 30 or so years. I don't think anyone would have been able to predict Skrillex, or anything like it, in the '60s or maybe even the '70s (though I'm unconfident about exactly when because my history is lacking).
Doesn't this suggest that it's most prudent to "expect the unexpected" when it comes to musical progress? I only gave a couple of examples, but I'm sure that more exist; generally, it seems like the emergence of new genres of music is a much less predictable process than the creation of songs within a given genre. You'd need quite convincing evidence to suggest that this time is different (barring some kind of civilizational collapse or "end of history"-style cultural equilibrium, of course).