I want to explain about something I have been thinking on for some time now.
An easy way to launch into this is with a concrete example, something I have realized these past few years as I have been playing piano more frequently and gaining a little bit more ability to sightread and improvise.
If music is important to you, and I ask you what music you love, then, if you are like me, you will have some personal answers to this question. Maybe songs or albums you had at certain stages in your life, that you associate with good or bad times, or people you knew, loss or joy you experienced, or so on. But, whatever the specifics, I think for you and for me and maybe for most present-day human beings the experience is one of listening.
We think about our favorite music in terms of the conversation between the performer or songwriter, and the listener. The artist paints in melody and harmony a picture of what it feels to be in a certain moment or situation, and they work to literally transport and synchronize our emotional state with theirs. It's wondrous if you think about it and something unique to music— though maybe not— other art can certainly transport us too.
But this is only one possible relationship; the other one is to make music.
This is a bit of an ananchronism. The common way, today, to experience (let's say) the music of The Barenaked Ladies is not to form a Barenaked Ladies cover band.
Even though we can relate in an intense, personal way by listening to music, I think it's actually an oddity of our modern condition.
What prompted this for me is the gradual realization that a lot of "western classical" music is not meant primarily as a conversation between performer and listener, but composer and performer.
A good example is Bach's Well Tempered Clavier. As much as this is nice to listen to, you actually can't understand it very well unless you play it. For one, it is so wondrous in it's ability to be played. Just by listening you won't be be aware of all the little "finger tricks" present, and if I can use a word, the at least for me these don't come across as something difficult so much as something playful or cute.
Bach isn't trying to make you do something impossible with your fingers, he is trying to show you your fingers can do things you didn't think of them ever doing in the first place. It's a special kind of conversation.
Part of the enjoyment, too, of playing music is maybe what is originally meant by the phrase "fugue state".
I have to kind of digress here and explain my own experience with music.
One way I feel I have missed out a ton with music is I just haven't ever played like, in a band or anything like that. What a terrible waste, so far, of my life. People who in their twenties or as they get older enjoy just playing with other people are really getting so much more out of music than you can by listening to it. I just haven't had this in my life, and I think it's because mostly I just learned to play "classical" piano and these skills are not very transferrable to playing music with other people, at least not until you get to a very high level.
Part of the way classical music is taught is, well, muscle memory. I think most of us are farmiliar with this interesting effect, but basically if you play the same piece over and over again, the physical feeling of it becomes somehow ingrained, and it does associate with the emotional feeling of the music.
The experience of playing this way, learning a single piece of music by playing it over and over, working through the tricky parts, and gradually forming musicle memory-- even memorizing sometimes-- that is what I had when I was younger.
You just learn to play the notes on the page so many times over that they sort of come out of your fingers automatically.
I should also stop and explain that I'm not, remotely, good at any of this. I never reached any kind of high level. But I still enjoy playing piano a lot, and I've experienced this way of learning music personally, so in that way, yes, I do know what I'm talking about. (But not as much as many, many others' do... I get that!)
But this isn't how I play music anymore. At some point, I disallowed myself to ever repeat a piece of music. So for instance, if playing through the Beethoven Sonatas, I do not allow myself ever to play a movement or sonata twice in a row. I sight-read it, then move on always in sequence. I have done this for years with three sets of music: Bach's Well Tempered Clavier, Mozart Piano Sonatas, and Beethoven Piano Sonatas (except until recently I just did not have the mental stamina to make it through #29, so I only played that far.)
(There are also some other books in the mix, and recently I am adding more to the regime, but... this paints a pretty good picture. Note that this is actually kind of a lot of music to get through— at least as a hobby— even if it's not very broad...)
(Over time, I also add this prohibition to repeating any notes or problematic bars/mistakes, as much as possible— in other words, if I mess something up, I have to play through it and recover.)
I've found this way, way, way more satisfying personally than just leaning (say) one Beethoven sonata to a level that someone else might conceivably actually want to hear me play it. Maybe this isn't a very considerate way to play music but it is rewarding.
Over the years, I've gotten better at this, bit by bit. It's become really, really satisfying and incredibly compelling and fun to perform classical music this way. I've also added more improvisation and I would make alarmingly large bets that if you heard Mozart perform one of his sonatas there is a zero percent chance you would hear the notes on the page, the way it's done today.
I have had teachers who can easily sight-read more or less all of this music, too, so I am basically just an amateur surmounting the toenail of what is possible here. I think these abilities are common for anyone who is pursuing music. But again-- I'm just describing what I've experienced, and trying to frame some ideas I have. I'm certainly not trying to give advice on how to become a great pianist!
So anyways, what's a "fugue state"?
Actually, it's what you get playing Rock Band. There is a kind of magic to these games, and it's just this: you are reading ahead of what you are playing. I contend that "fugue state" is just that— reading or processing information a little bit (say a second or so) ahead of what your body is executing. It's wonderful and I find Rock Band actually does create this effect. It really is like playing music, even though it's not.
(And I say Rock Band, because for awhile there this was a really popular experience, but I also think about the first game, I think, to do this, was a PSX game, was it called, I think, AudioSurf? And of course other "music games" do/did this too. Is Beat Sabre a bit unique in being more of a DDR-style, full-body experience? Is it the closest thing to Taiko drumming that isn't actually that? I guess probably? I haven't played it.)
I mean, at this point you are wading waist-high through a muddy bog of one mediocre pianoist's opinion, but I say that in playing a Bach fugue, the magic you actually experience is that when you are able to really play it sight reading, not musicle memory, your input buffer, so to speak, is fully saturated, and very little exists in your brain except this wondrous experience of intaking music and planning movements for your fingers and body. You aren't thinking about how you do this, because you tend to stumble when you do.
This is actually how we move our bodies generally— our brain can kind of feel in advance what is going to happen, and plan a motion in spacetime to navigate this. It's why when you learn a new physical skill, say like skateboarding, riding a bike, or skiing, it takes so much practice and you lose your balance so much. Your brain has no idea what is actually going to happen— no intuitive, automatic idea at least. But gradually you figure it out, and then before you know it you are adjusting your balance well-in-advance of whatever physical law is about to affect it.
This is the same thing as fugue state, or at least, fugue state depends on this facility of the human brain.
This can certainly happen with some videogames, too. Classical Monster Hunter games are like this. (Or at least, in my experience one or two of them are: I played Freedom Unite! a ton on PS Vita, and you fully play that game 2 or 3 seconds into the future. It's really, really cool. The same is baically true of MH4U on 3DS, though maybe a touch less pronounced.)
So yeah— rounding this out, if you like music, as a listener, what I'm saying is you could think about playing it, too— and your job in playing it is not to get good enough that anyone would particularly want to hear you play (or at least, not necessarily) but just to realize that it's a unique way to enjoy music, and valuable in and of itself. The audience doesn't really have to be part of it.
(A similar split between playing and watching videogames, has also formed, with streaming and speedrunning and so-on.)
If you already make music, have you thought about writing it down in a way that someone else could experience it by playing it? This is what I mean about classical music being anachronistic— today we don't think very much of that relationship, but it's certainly something to explore. I don't really know my music history, but I'd love to learn e.g., how many copies of different piano sonatas Beethoven sold, and how commonly they were played at a less-than-stellar level, like I would enjoy them myself today. (Or maybe I'm out to lunch here.)
Finally, I think about children singing, which comes naturally to them and is the most common way for them to experience a song. I think about singing at concerts, and how special that seems. And I think about singing at Church, where it is suddenly normal (or at least, when I was a kid) for "non musical" people to experience performing music: in Church, almost everybody sang the hymns even though most people would not have sang songs in very many other contexts. It's a bit interesting-- they just needed a social context, maybe one stretching a bit back in time, so in a sense anachronistic, to make this acceptable.