The ultimate destiny of the human race is the greatest moral perfection, provided that it is achieved through human freedom, whereby alone man is capable of the greatest happiness.
The desire which a man has for a woman is not directed towards her because she is a human being, but because she is a woman ; that she is a human being is of no concern to the man; only her sex is the object of his desires.
We ourselves introduce that order and regularity in the appearance which we entitle "nature". We could never find them in appearances had we not ourselves, by the nature of our own mind, originally set them there.
. . . as to moral feeling, this supposed special sense, the appeal to it is indeed superficial when those who cannot think believe that feeling will help them out, even in what concerns general laws: and besides, feelings which naturally differ infinitely in degree cannot furnish a uniform standard of good and evil, nor has any one a right to form judgments for others by his own feelings. . . .
Enlightenment is man's leaving his self-caused immaturity. Immaturity is the incapacity to use one's intelligence without the guidance of another. Such immaturity is self-caused if it is not caused by lack of intelligence, but by lack of determination and courage to use one's intelligence without being guided by another. Sapere Aude! Have the courage to use your own intelligence! is therefore the motto of the enlightenment.
The instruction of children should aim gradually to combine knowing and doing. Among all sciences mathematics seems to be the only one of a kind to satisfy this aim most completely.
This spirit of freedom is expanding even where it must struggle against the external obstacles of governments that misunderstand their own function. Such governments are illuminated by the example that the existence of freedom need not give cause for the least concern regarding public order and harmony in the commonwealth. If only they refrain from inventing artifices to keep themselves in it, men will gradually raise themselves from barbarism.
The existence of the Bible, as a book for the people, is the greatest benefit which the human race has ever experienced. Every attempt to belittle it is a crime against humanity.