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Happiness is not an ideal of reason, but of imagination.

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The whole interest of my reason, whether speculative or practical, is concentrated in the three following questions: What can I know? What should I do...more

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Enlightenment is man's release from his self-incurred tutelage. Tutelage is man's inability to make use of his understanding without direction from an...more

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...new prejudices will serve as well as old ones to harness the great unthinking masses.For this enlightenment, however, nothing is required but freed...more

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Laziness and cowardice are the reasons why so great a portion of mankind, after nature has long since discharged them from external direction (natural...more

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Metaphysics... is nothing but the inventory of all we possess through pure reason, ordered systematically. Nothing here can escape us, because what re...more

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(On the seeming futility of metaphysics) Why then has nature afflicted our reason with the restless striving for such a path, as if it were one of rea...more

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...Reason should take on anew the most difficult of all its tasks, namely, that of self-knowledge, and to institute a court of justice, by which reaso...more

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[At the beginning of modern science], a light dawned on all those who study nature. They comprehended that reason has insight only into what it itself...more

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All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

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Skepticism is thus a resting-place for human reason, where it can reflect upon its dogmatic wanderings and make survey of the region in which it finds...more

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Enlightenment is man's emergence from his self-imposed immaturity. Nothing is required for this enlightenment except freedom; and the freedom in quest...more

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...[N]ature generally in the distribution of her capacities has adapted the means to the end... [so nature's] true destination must be to produce a wi...more

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...We find that the more a cultivated reason applies itself with deliberate purpose to the enjoyment of life and happiness, so much the more does the ...more

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In the physical constitution of an organized being, that is, a being adapted suitably to the purposes of life, we assume it as a fundamental principle...more