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.
Two things fill the mind with ever-increasing wonder and awe, the more often and the more intensely the mind of thought is drawn to them: the starry heavens above me and the moral law within me... Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.
There is needed, no doubt, a body of servants (ministerium) of the invisible church, but not officials (officiales), in other words, teachers but not dignitaries, because in the rational religion of every individual there does not yet exist a church as a universal union (omnitudo collectiva).
Nature does nothing in vain, and in the use of means to her goals she is not prodigal. Her giving to man reason and the freedom of the will which depends upon it is clear indication of her purpose. Man accordingly was not to be guided by instinct, not nurtured and instructed with ready-made knowledge; rather, he should bring forth everything out of his own resources.
We find that the more a cultivated reason devotes itself to the aim of enjoying life and happiness, the further does man get away from true contentment.
The universal and lasting establishment of peace constitutes not merely a part, but the whole final purpose and end of the science of right as viewed within the limits of reason.
If an offender has committed murder, he must die. In this case, no possible substitute can satisfy justice. For there is no parallel between death and even the most miserable life, so that there is no equality of crime and retribution unless the perpetrator is judicially put to death.