Every man is to be respected as an absolute end in himself; and it is a crime against the dignity that belongs to him as a human being, to use him as a mere means for some external purpose.
Religion is too important a matter to its devotees to be a subject of ridicule. If they indulge in absurdities, they are to be pitied rather than ridiculed.
Beneficence is a duty. He who frequently practices it, and sees his benevolent intentions realized, at length comes really to love him to whom he has done good. When, therefore, it is said, "Thou shalt love thy neighbor as thyself," it is not meant, thou shalt love him first and do him good in consequence of that love, but, thou shalt do good to thy neighbor; and this thy beneficence will engender in thee that love to mankind which is the fulness and consummation of the inclination to do good.
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.
Seek not the favor of the multitude; it is seldom got by honest and lawful means. But seek the testimony of few; and number not voices, but weigh them.
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.
Parents usually educate their children merely in such a manner than however bad the world may be, they may adapt themselves to its present conditions. But they ought to give them an education so much better than this, that a better condition of things may thereby be brought about by the future.
Ours is an age of criticism, to which everything must be subjected. The sacredness of religion, and the authority of legislation, are by many regarded as grounds for exemption from the examination by this tribunal, But, if they are exempted, and cannot lay claim to sincere respect, which reason accords only to that which has stood the test of a free and public examination.
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.
A science of all these possible kinds of space [the higher dimensional ones] would undoubtedly be the highest enterprise which a finite understanding could undertake in the field of geometry... If it is possible that there could be regions with other dimensions, it is very likely that God has somewhere brought them into being.
All thought must, directly or indirectly, by way of certain characters, relate ultimately to intuitions, and therefore, with us, to sensibility, because in no other way can an object be given to us.
Even if a civil society were to be dissolved by the consent of all its members (e.g., if a people inhabiting an island decided to separate and disperse throughout the world), the last murderer remaining in prison would first have to be executed, so that each has done to him what his deeds deserve and blood guilt does not cling to the people for not having insisted upon this punishment; for otherwise the people can be regarded as collaborators in his public violation of justice.