Everyone dies. Everyone leaves. What matters is the things you build together before they go. What matters is the part of them that continues in you when they're gone.

Science isn't done by consensus. It's done by rigorous testing.

there were crimes and quarrels, alongside kindness and cooperation; there were people who loved each other and people who did not; it was a human world.

And then he thought: Is this how idiots rationalize their stupidity to themselves?

Human beings are free except when humanity needs them. Maybe humanity needs you. To do something. Maybe humanity needs me—to find out what you're good for. We might both do despicable things, Ender, but if humankind survives, then we were good tools.

'So if we can we'll kill every last of the buggers, and if they can they'll kill every last one of us. As for me,' said Ender, 'I'm in favor of surviving'.

There's only one thing that will make them stop hating you. And that's being so good at what you do that they can't ignore you