Even great spirits have only their five-fingers' breadth of experience - just beyond it their thinking ceases and their endless empty space and stupidity begins.
But the greatest error of all the rest is the mistaking or misplacing of the last or farthest end of knowledge: for men have entered into a desire of learning and knowledge, sometimes upon a natural curiosity and inquisitive appetite; sometimes to entertain their minds with variety and delight; sometimes for ornament and reputation; and sometimes to enable them to victory of wit and contradiction; and most times for lucre and profession; and seldom sincerely to give a true account of their gift of reason, to the benefit and use of men.
Upon a given body to generate and superinduce a new nature or new natures is the work and aim of human power. To discover the Form of a given nature, or its true difference, or its causal nature, or fount of its emanation... this is the work and aim of human knowledge.
Enlightenment is the liberation of man from his self-caused state of minority... Supere aude! Dare to use your own understanding!is thus the motto of the Enlightenment.
Conversation with a friend will only bear good fruit of knowledge when both think only of the matter under consideration and forget that they are friends.
Metaphysical world.- It is true, there could be a metaphysical world; the absolute possibility of it is hardly to be disputed. We behold all things through the human head and cannot cut off this head; while the question nonetheless remains what of the world would still be there if one had cut it off.