Carl Sagan Quotes

To avoid being drawn into error, keep a firm grip on the truth.

A man's most valuable trait is a judicious sense of what not to believe.

Logic and truth are two very different things, but they often look the same to the mind that's performing the logic.

For dear me, why abandon a belief Merely because it ceases to be true

Argument is not always truth.

You have to keep your mind as wide-open as your eyes, because almost nothing is what it seems.

The greatest challenge facing mankind is the challenge of distinguishing reality from fantasy, truth from propaganda.

Man is an emotional animal, occasionally rational; and through his feelings he can be deceived to his heart's content.

The first lesson about trusting your senses is: don't. Just because you believe something to be true, just because you know it's true, that doesn't mean it is true.

You have to be careful what you think you know.

The duty of criticism is neither to depreciate nor dignify by partial representations, but to hold out the light of reason, whatever it may discover; and to promulgate the determinations of truth, whatever she shall dictate

It is morally as bad not to care whether a thing is true or not, so long as it makes you feel good, as it is not to care how you got your money as long as you have got it.

If it doesn't make sense, it's usually not true.

Reason deceives us more often than does nature.

One does not want to be deceived, under the supposition that it is injurious, dangerous, or fatal to be deceived.

Most of the time you should use reason, there is no doubt about that because gut often makes us susceptible to lots of different biases, particularly if what you're deciding is something that you really, that expertise can be brought to bear on it, there is a way in which you can align the odds, so then you should really use reason.

It begins with skepticism. The history of human folly, and our own susceptibility to illusions and fallacies, tell us that men and women are fallible.

Talk about rationality can get very confusing unless the things with which rationality deals are also included.

Even as wisdom often comes from the mouths of babes, so does it often come from the mouths of old people. The golden rule is to test everything in the light of reason and experience, no matter from where it comes.

I know too well that these arguments from probabilities are imposters, and unless great caution is observed in the use of them, they are apt to be deceptive.

To think truly is noble and to be deceived is base.

Proof is boring. Proof is tiresome. Proof is an irrelevance. People would far rather be handed an easy lie than search for a difficult truth, especially if it suits their own purposes.

I hope you become comfortable with the use of logic without being deceived into concluding that logic will inevitably lead you to the correct conclusion.

Reason is so unreasonable, that few people can say they are in possession of it.

Seeing is not believing - it is only seeing.