The light dove, in free flight cutting through the air the resistance of which it feels, could get the idea that it could do even better in airless space. Likewise, Plato abandoned the world of the senses because it posed so many hindrances for the understanding, and dared to go beyond it on the wings of the ideas, in the empty space of pure understanding.
Upon the solution of this problem, or upon sufficient proof of the impossibility of synthetical knowledge a priori, depends the existence or downfall of metaphysics.
Marriage...is the union of two people of different sexes with a view to the mutual possession of each other's sexual attributes for the duration of their lives.
Men will not understand ... that when they fulfil their duties to men, they fulfil thereby God's commandments; that they are consequently always in the service of God, as long as their actions are moral, and that it is absolutely impossible to serve God otherwise.
It is the Land of Truth (enchanted name!), surrounded by a wide and stormy ocean, the true home of illusion, where many a fog bank and ice, that soon melts away, tempt us to believe in new lands, while constantly deceiving the adventurous mariner with vain hopes, and involving him in adventures which he can never leave, yet never bring to an end.
Natural science physics contains in itself synthetical judgments a priori, as principles. ... Space then is a necessary representation a priori, which serves for the foundation of all external intuitions.
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.
That Logic has advanced in this sure course, even from the earliest times, is apparent from the fact that, since Aristotle, it has been unable to advance a step, and thus to all appearance has reached its completion.
Both love of mankind, and respect for their rights are duties; the former however is only a conditional, the latter an unconditional, purely imperative duty, which he must be perfectly certain not to have transgressed who would give himself up to the secret emotions arising from benevolence.