Here's something useless I was thinking about this morning. Let's say, by force of magic or advanced technology (maybe via my privatized Pentagon scheme), I was transported back in time to the Dark Ages in Europe. Could I, with my 21st century brain, actually contribute anything super-meaningful to the era? Could I use my knowledge of the future to transform the world?

Sadly, I doubt it.

Let's start with what I know: A lot, it seems, about Galois Theory and algebraic topology. I can explain, step by step, why Hilbert's Tenth Problem is unsolvable. But who would care? On a practical level, I'm not entirely sure I could reinvent calculus from scratch—nor convince my Dark Ages bretheren how to get from their sand-scratching to the new, improved mathematics. Nor explain what they should actually do with their derivatives and integrals. Meanwhile, I have nothing to offer them on the engineering front. Nothing. I know what gravity is, and they wouldn't. But I'm not sure I could figure out how to "produce" electricity, or explain the principles of bridge-building (there's… a keystone… right?). Certainly no amount of fiddling on my part would ever produce a light-bulb, or a telephone, or the steam engine. Perhaps I could beat that Gutenberg fellow to the punch on the printing-press, that doesn't seem so tricky.

Now politics. What on earth could I tell anyone about democracy? These things obviously require broad attitudinal changes, and not a single, not-especially-eloquent, agitator. My crazy ideas about the Catholic Church would just get me the rack, or worse. Maybe with enough observation I could suggest some interesting modifications to their barter system—the value of central banking, for instance. But it would probably take a lot of fiddling and I'd probably botch it up. On the other hand, simply knowing what germs actually are could go a long ways to improving public health. But that's sort of lame.

Maybe I could be a great writer—thanks to plagiarism. I have, for instance, a good deal of MacBeth, King Lear, and some other early works tucked away in memory. So maybe I could write them down and pawn them off as my own. But the parts I didn't have would assuredly suck, and I probably wouldn't know much about marketing these plays, or hobnobbing with other playwrights, or whatever it is you do. And unless these plays were released at just the right time, to just the right audience, they would fall into obscurity. (And then centuries later, poor Shakespeare would have to suffer accusations of plagiarism if he tried to write MacBeth.)

At any rate, the Connecticut Yankee in King Arthur's Court, if I remember correctly, was a big hit because he had a lot of practical and oddly useful knowledge (like knowing when eclipses occurred, or how to create electricity). Educational standards, I'm afraid, have fallen markedly since his day.