“Old men tend to forget what thought was like in their youth; they forget the quickness of the mental jump, the daring of the youthful intuition, the agility of the fresh insight. They become accustomed to the more plodding varieties of reason, and because this is more than made up by the accumulation of experience, old men think themselves wiser than the young.”

“He had read much, if one considers his long life; but his contemplation was much more than his reading. He was wont to say that if he had read as much as other men he should have known no more than other men.”

“Do not forget that a traitor within our ranks, known to us, can do more harm to the enemy than a loyal man can do good to us.”

“A number of years ago, when I was a freshly-appointed instructor, I met, for the first time, a certain eminent historian of science. At the time I could only regard him with tolerant condescension.I was sorry of the man who, it seemed to me, was forced to hover about the edges of science. He was compelled to shiver endlessly in the outskirts, getting only feeble warmth from the distant sun of science- in-progress; while I, just beginning my research, was bathed in the heady liquid heat up at the very center of the glow.In a lifetime of being wrong at many a point, I was never more wrong. It was I, not he, who was wandering in the periphery. It was he, not I, who lived in the blaze.I had fallen victim to the fallacy of the 'growing edge;' the belief that only the very frontier of scientific advance counted; that everything that had been left behind by that advance was faded and dead.But is that true? Because a tree in spring buds and comes greenly into leaf, are those leaves therefore the tree? If the newborn twigs and their leaves were all that existed, they would form a vague halo of green suspended in mid-air, but surely that is not the tree. The leaves, by themselves, are no more than trivial fluttering decoration. It is the trunk and limbs that give the tree its grandeur and the leaves themselves their meaning.There is not a discovery in science, however revolutionary, however sparkling with insight, that does not arise out of what went before. 'If I have seen further than other men,' said Isaac Newton, 'it is because I have stood on the shoulders of giants.”

“But you haven't tried. You haven't tried once. First you refused to admit that there was a menace at all! Then you reposed an absolutely blind faith in the Emperor! Now you've shifted it to Hari Seldon. Throughout you have invariably relied on authority or on the past—never on yourselves."His fists balled spasmodically. "It amounts to a diseased attitude—a conditioned reflex that shunts aside the independence of your minds whenever it is a question of opposing authority. There seems no doubt ever in your minds that the Emperor is more powerful than you are, or Hari Seldon Wiser. And that's wrong don't you see?"For some reason, no one cared to answer him.Hardin continued: "It isn't just you. It's the whole Galaxy. Pirenne heard Lord Dorwin's idea of scientific research. Lord Dorwin thought the way to be a good archaeologist was to read all the books on the subject—written by men who were dead for centuries. He thought that the way to solve archaeological puzzles was to weight the opposing authorities. And Pirenne listened and made no objections. Don't you see that there's something wrong with that?"Again the note of near-pleading in his voice.Again no answer. He went on: "And you men and half of Terminus as well are just as bad.. We sit here, considering the Encyclopedia the all-in-all. We consider the greatest end of science is the classification of past data. It is important, but is there no further work to be done? We're receding and forgetting, don't you see? Here in the Periphery they've lost nuclear power. In Gamma Andromeda, a power plant has undergone meltdown because of poor repairs, and the Chancellor of the Empire complains that nuclear technicians are scarce. And the solution? To train new ones? Never! Instead they're to restrict nuclear power."And for the third time: "Don't you see? It's galaxy-wide. It's a worship of the past. It's a deterioration—a stagnation!”

“The human mind works at low efficiency. Twenty percent is the figure usually given. When, momentarily, there is a flash of greater power, it is termed a hunch, or insight, or intuition.”

“Surely, if we take on thinking partners––or, at the least, thinking servants––in the form of machines, we will be more comfortable with them, and will relate to them more easily, if they are shaped like humans. It will be easier to be friends with human-shaped robots than with specialized machines of unrecognizable shape. And I sometimes think that, in the desperate straits of humanity today, we would be grateful to have nonhuman friends, even if they are only the friends we build ourselves.”