“...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.”

“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.”

“But if you caught my informant,' said Achilles, 'why in the world would Chamrajnagar—or Graff, if it was him—launch the shuttle anyway? Was catching me doing something naughty so important they’d risk a shuttle and it’s crew just to catch me? I find that quite… flattering. Sort of like winning the Nobel Prize for scariest villain.”

“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.”

“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 only 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. I will devise the strategy of your army, and you will learn to be quick and discover what tricks the enemy has for you. Remember, boy. From now on the enemy is more clever than you. From now on the enemy is stronger than you. From now on you are always about to lose.”

“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.”

“If you give orders and explain nothing, you might get obedience, but you'll get no creativity. If you tell them your purpose, then when your original plan is shown to be faulty, they'll find another way to achieve your goal. Explaining to your men doesn't weaken their respect for you, it proves your respect for them.”