The eye sees only what the mind is prepared to comprehend.

When we find a thinker reflecting or echoing an apparently erroneous, narrow, or even illogical thought that was popular or authoritative in his time, we must never rule out the possibility that what we have discovered is not the limit of his vision but only an example of his deliberate rhetorical accommodation to reigning prejudice which he does not share but thinks it best not to expose.

The psychologists and the metaphysicians wrangle endlessly over the nature of the thinking process in man, but no matter how violently they differ otherwise they all agree that it has little to do with logic and is not much conditioned by overt facts.

Every step in human progress, from the first feeble stirrings in the abyss of time, has been opposed by the great majority of men. Every valuable thing that has been added to the store of man's possessions has been derided by them when it was new, and destroyed by them when they had the power. They have fought every new truth ever heard of, and they have killed every truth-seeker who got into their hands.

The human race is divided into two sharply differentiated and mutually antagonistic classes, almost two genera- a small minority that plays with ideas and is capable of taking them in, and a vast majority that finds them painful, and is thus arrayed against them, and against all who have traffic with them. The intellectual heritage of the race belongs to the minority, and to the minority only. The majority has no more to do with it than it has to do with ecclesiastic politics on Mars. In so far as that heritage is apprehended, it is viewed with enmity. But in the main it is not apprehended at all.

Any man who inflicts the human race with ideas must be prepared to see them misunderstood.