Do not use power to suppress opinions you think pernicious, for if you do the opinions will suppress you.

From the height of their disillusionment they look down upon those whom they despise as simple souls. For my part I have no sympathy with this outlook. All disenchantment is to me a malady, which, it is true, certain circumstances may render inevitable, but which none the less, when it occurs, is to be cured as soon as possible, not to be regarded as a higher form of wisdom.

There can't be a practical reason for believing something that is not true.

I am firm; YOU are obstinate; HE is a pig-headed fool.

One of the chief obstacles to intelligence is credulity, and credulity could be enormously diminished by instructions as to the prevalent forms of mendacity.

I am not myself in any degree ashamed of having changed my opinions.

The scientific attitude of mind involves a sweeping away of all other desires in the interests of the desire to know-it involves suppression of hopes and fears, loves and hates, and the whole subjective emotional life, until we become subdued to the material, able to see it frankly, without preconceptions, without bias, without any wish except to see it as it is, and without any belief that what it is must be determined by some relation, positive or negative, to what we should like it to be, or to what we can easily imagine it to be.