“The criminal misuse of time was pointing out the mistakes. Catching them―noticing them―that was essential. If you did not in your own mind distinguish between useful and erroneous information, then you were not learning at all, you were merely replacing ignorance with false belief, which was no improvement. The part of the man's statement that was true, however, was about the uselessness of speaking up. If I know that the teacher is wrong, and say nothing, then I remain the only one who knows, and that gives me an advantage over those who believe the teacher.”

“If you did not in your own mind distinguish between useful and erroneous information, then you were not learning at all, you were merely replacing ignorance with false belief, which was no improvement.”

“...you seemed to be listening to me, not to find out useful information, but to try to catch me in a logical fallacy. This tells us all that you are used to being smarter than your teachers, and that you listen to them in order to catch them making mistakes and prove how smart you are to the other students. This is such a pointless, stupid way of listening to teachers that it is clear you are going to waste months of our time before you finally catch on that the only transaction that matters is a transfer of useful information from adults who possess it to children who do not, and that catching mistakes is a criminal misuse of time.”

“You know what I was thinking? [Ruthie] got so excited when she was spouting this ahistorical countertextual nonsense, and I caught myself thinking, 'What an idiot her teacher must be,' and thinking about her teacher made me realize - the kind of excitement she was showing as she mindlessly spouted back the nonsense she learned in college, that's just like the excitement some of my own students show. And it occurred to me that what we professors think of as a 'brilliant student' is nothing but a student who is enthusiastically converted to whatever idiotic ideas we've been teaching them.""Self-knowledge is a painful thing," said Esther. "To learn that your best students are parrots after all.”

“(Rigg) had often complained that all these languages were useless, and Father had only said, "A man who speaks but one language understands none.”

“There's always moral instruction whether the writer inserts it deliberately or not. The least effective moral instruction in fiction is that which is consciously inserted. Partly because it won't reflect the storyteller's true beliefs, it will only reflect what he BELIEVES he believes, or what he thinks he should believe or what he's been persuaded of. But when you write without deliberately expressing moral teachings, the morals that show up are the ones you actually live by. The beliefs that you don't even think to question, that you don't even notice-- those will show up. And that tells much more truth about what you believe than your deliberate moral machinations.”

“An enemy, Ender Wiggin," whispered the old man. "I am your enemy, the first one you've ever had who was smarter than you. There is no teacher but the enemy. No one but the enemy will tell you what the enemy is going to do. No one but the enemy will ever teach you how to destroy and conquer. Only the enemy shows you where you are weak. Only the enemy tells you where he is strong. And the rules of the game are what you can do to him and what you can stop him from doing to you. I am your enemy from now on. From now on I am your teacher.”