“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?”

“And then Harry Potter had launched in to a speech that was inspiring, yet vague. A speech to the effect that Fred and George and Lee had tremendous potential if they could just learn to be weirder. To make people's live surreal, instead of just surprising them with the equivalents of buckets of water propped above doors. (Fred and George had exchanged interested looks, they'd never thought of that one.) Harry Potter had invoked a picture of the prank they'd pulled on Neville - which, Harry had mentioned with some remorse, the Sorting Hat had chewed him out on - but which must have made Neville doubt his own sanity. For Neville it would have felt like being suddendly transported into an alternate universe. The same way everyone else had felt when they'd seen Snape apologize. That was the true power of pranking.”

“Most Muggles lived in a world defined by the limits of what you could do with cars and telephones. Even though Muggle physics explicitly permitted possibilities like molecular nanotechnology or the Penrose process for extracting energy from black holes, most people filed that away in the same section of their brain that stored fairy tales and history books, well away from their personal realities: Long ago and far away, ever so long ago.”

“And someday when the descendants of humanity have spread from star to star they won’t tell the children about the history of Ancient Earth until they’re old enough to bear it and when they learn they’ll weep to hear that such a thing as Death had ever once existed”

“You couldn't changed history. But you could get it right to start with. Do something differently the FIRST time around.This whole business with seeking Slytherin's secrets... seemed an awful lot like the sort of thing where, years later, you would look back and say, 'And THAT was where it all started to go wrong.'And he would wish desperately for the ability to fall back through time and make a different choice. Wish granted. Now what?”

“Aside from helping people with their homework, or anything else they needed, she really didn't know how to meet people. She didn't feel like she was a shy person. She thought of herself as a take-charge sort of girl. And yet, somehow, if there wasn't some request along the lines of "I can't remember how to do long division" then it was just too awkward to go up to someone and say... what? She'd never been able to figure out what. And there didn't seem to be a standard information sheet, which was ridiculous. The whole business of meeting people had never seemed sensible to her. Why did she have to take all the responsibility herself when there were two people involved? Why didn't adults ever help? She wished some other girl would just walk up to her and say, "Hermione, the teacher told me to be friends with you".”

“He really really really shouldn't have done that. Amazing how much more obvious that became one second after it was too late.”