There ain't no such thing as a free lunch.

— The Moon Is a Harsh Mistress

Love is that condition in which the happiness of another person is essential to your own.

— Stranger in a Strange Land

Specialization is for insects.

— Time Enough for Love

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly.

— Time Enough for Love

Never appeal to a man's "better nature." He may not have one. Invoking his self-interest gives you more leverage.

— Time Enough for Love

The meek will inherit the Earth, but they won't deserve it.

— Time Enough for Love

One man's "magic" is another man's engineering. "Supernatural" is a null word.

— Expanded Universe (1980)

Secrecy is the beginning of tyranny.

— Attributed to Heinlein

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Never underestimate the power of human stupidity.

— Time Enough for Love

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Political labels — royalist, communist, democrat, populist, fascist, liberal, conservative, and so on — are never basic criteria. The human race divides politically into those who want people to be controlled and those who have no such desire.

— Take Back Your Government (1992)

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A generation which ignores history has no past and no future.

— Attributed

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If you don't care, then it doesn't matter. And if it doesn't matter, then it's not worth fighting about.

— The Moon Is a Harsh Mistress

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The ability to perceive or think differently is more important than the knowledge gained.

— Stranger in a Strange Land

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Man is not a rational animal; he is a rationalizing animal.

— Attributed

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Courage is not the absence of fear, but rather the assessment that something else is more important than fear.

— Attributed

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To be nobody but yourself in a world which is doing its best to make you everybody else...

— Misattributed

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