It is difficult for the isolated individual to work himself out of the immaturity which has become almost natural for him.

Human reason is by nature architectonic.

Two things fill the mind with ever new and increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me. I do not seek or conjecture either of them as if they were veiled obscurities or extravagances beyond the horizon of my vision; I see them before me and connect them immediately with the consciousness of my existence.

It is often necessary to make a decision on the basis of knowledge sufficient for action but insufficient to satisfy the intellect.

This can never become popular, and, indeed, has no occasion to be so; for fine-spun arguments in favour of useful truths make just as little impression on the public mind as the equally subtle objections brought against these truths. On the other hand, since both inevitably force themselves on every man who rises to the height of speculation, it becomes the manifest duty of the schools to enter upon a thorough investigation of the rights of speculative reason, and thus to prevent the scandal which metaphysical controversies are sure, sooner or later, to cause even to the masses.

I learned to honor human beings, and I would find myself far more useless than the common laborer if I did not believe that this consideration could impart to all others a value establishing the rights of humanity.

Always treat people as ends in themselves, never as means to an end.