If you could go into the past and bring someone to the present to show them what the world was like, and how they were remembered, who would you pick?
That's a huge question because there's so many directions you could go with the answer. Imagine how Shakespeare would react to the esteem in which he is held, how shocked Charlemagne would be at the state of politics, how Jules Verne would be fascinated by the Internet, how gratified and discouraged Martin Luther King Jr. would be at how far we have and haven't come, how irritated Nietzsche would be at what people think he stood for. So to narrow it down, let's take it one topic at a time. Today's topic will be music, and in particular, how musicians and composers of the past would react to music today.
The first thing to consider is that anyone who had even the slightest interest in music who came from more than a hundred years ago would be reeling for a while at something we all take for granted: that music is something you can have any time you want, any minute of the day, or even all day long, and that most of us have it that way. It's a paradigm shift whose significance is easy to miss. Music used to be an event that required people to gather, and one couldn't become familiar with a song from repeated listening very quickly. How it was created depended on how it was consumed, and it's easy to underestimate the significance of the difference.
Setting that aside, how would specific musicians or composers react to modern music?
One can't help imagine that Beethoven would be appalled (assuming you cured his deafness while you were curing his deadness), and that's about all you'd get out of him. (Doubly so if he'd heard "Roll Over Beethoven" by E.L.O., and trebly so if he'd heard the disco cover "A Fifth Of Beethoven".) Mozart would probably be appalled at first, but maybe would become eventually intrigued, too. Haydn would be amused, and Mahler would probably be excited, and working with Brian Eno. I can't quite pin down how Bach would react, but I do know that the first modern music I'd show him is gospel music from a southern Baptist church. I can't tell if Wagner would be listening to death metal, or refusing to consider anything but opera.
How about more modern people? Glenn Miller would probably take a little while to adjust but be pleased by the different forms music took after his day, and the progression by which each new style related to those before it. Cole Porter would be fascinated, but I bet he'd also be disappointed at how small a subset of the newly possible is actually being explored, and how much of what's popular is barely different from the stuff he and his contemporaries were doing. Aaron Copland would probably not have much by way of opinions; he'd be too busy writing scores for big Hollywood blockbusters. Carl Orff would be too, but he'd also be hating himself for doing it, where Copland would shrug and cash another check.
I imagine all of these people would be flattered in one way or another that they're still known, listened to, and studied. Beethoven was celebrated enough in his day that he would be only a little surprised, but I think Glenn Miller would be a little awed and gratified, and everyone else would fall somewhere in between.
If I could only bring forward one of those people I'd have to choose Bach just because I have the least firm an idea how he'd react, so it's the biggest question to have answered. (And I'd have to see what he thought of the works of Peter Schickele...)