Harry Potter and the Methods of Rationality

Are you so much better than Haukelid and Dumbledore, Harry Potter, that you'll be able to fight without a single casualty? Even in the world of comic books, the only reason a superhero like Batman even looks successful is that the comic-book readers only notice when Important Named Characters die, not when the Joker shoots some random nameless bystander to show off his villainy. Batman is a murderer no less than the Joker, for all the lives the Joker took that Batman could've saved by killing him. That's what the man named Alastor was trying to tell Dumbledore, and afterward Dumbledore regretted having taken so long to change his mind. Are you really going to try to follow the path of the superhero, and never sacrifice a single piece or kill a single enemy?

Fatigued, Harry turned his attention away from the dilemma for a moment, opened his eyes again to regard the hemisphere of night, which required no decisions from him.

Near the edge of his vision, the pale white crescent of the Moon, the light from which had left one-and-a-quarter seconds ago, around 375,000 kilometers of distance in Earth's space of simultaneity.

Above and to the side, Polaris, the North Star, the first star Harry had learned to identify in the sky by following the edge of the Big Dipper; that was actually a five-system with a brilliant central supergiant, 434 light-years from Earth. It was the first star whose name Harry had ever learned, so long ago that he couldn't have guessed how old he'd been.

The dim fog that was the Milky Way; so many billions of distant stars that they became an indistinct river, the plane of a galaxy that stretched 100,000 light-years across.

In the center of the constellation Andromeda, the star Andromeda, which was really the Andromeda Galaxy. The nearest galaxy to the Milky Way, 2.4 million light-years away, containing an estimated trillion stars.

Numbers like those made 'infinity' pale by comparison, because 'infinity' was just featureless and blank. Thinking that the stars were 'infinitely' distant was a lot less scary than trying to work out what 2.4 million light-years amounted to in meters. 2.4 million light-years, times 31 million seconds in a year, times a photon moving at 300,000,000 meters per second...

It was strange to think that such distances might not be unreachably far away. Magic was loose in the universe, things like Time-Turners and broomsticks. Had anyone even measured the speed of a portkey, or a phoenix? And the human understanding of magic couldn't possibly be anywhere near the underlying laws. What would you be able to do with magic if you really understood it?

A year ago, Dad had gone to the Australian National University in Canberra for a conference where he'd been an invited speaker, and he'd taken Mum and Harry along. And they'd all visited the National Museum of Australia, because, it had turned out, there was basically nothing else to do in Canberra. The glass display cases had shown rock-throwers crafted by the Australian aborigines - like giant wooden shoehorns, they'd looked, but smoothed and carved and ornamented with the most painstaking care. In the 40,000 years since anatomically modern humans had migrated to Australia from Asia, nobody had invented the bow-and-arrow. It really made you appreciate how non-obvious was the idea of Progress. Why would you even think of Invention as something important, if all your history's heroic tales were of great warriors and defenders instead of Thomas Edison? How could anyone possibly have suspected, while carving a rock-thrower with painstaking care, that someday human beings would invent rocket ships and nuclear energy?

Could you have looked up into the sky, at the brilliant light of the Sun, and deduced that the universe contained greater sources of energy than mere fire? Would you have realized that if the fundamental physical laws permitted it, someday humans would tap the same energies as the Sun? Even if nothing you could imagine doing with rock-throwers or woven pouches - no pattern of running across the savannah and nothing you could obtain by hunting animals - would accomplish that even in imagination?