Psychologists have hitherto failed to realize that imagination is a necessary ingredient of perception itself.

I ought never to act except in such a way that I could also will that my maxim should become a universal law.

If I am to constrain you by any law, it must be one by which I am also bound.

Even philosophers will praise war as ennobling mankind, forgetting the Greek who said: 'War is bad in that it begets more evil than it kills.'

The sight of a being who is not adorned with a single feature of a pure and good will, enjoying unbroken prosperity, can never give pleasure to an impartial rational spectator. Thus a good will appears to constitute the indispensable condition even of being worthy of happiness.

The function of the true state is to impose the minimum restrictions and safeguard the maximum liberties of the people, and it never regards the person as a thing.

The means employed by Nature to bring about the development of all the capacities of men is their antagonism in society, so far as this is, in the end, the cause of a lawful order among men.

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.

Only the descent into the hell of self-knowledge can pave the way to godliness.

To a high degree we are, through art and science, cultured. We are civilized -- perhaps too much for our own good -- in all sorts of social grace and decorum. But to consider ourselves as
having reached morality -- for that, much is lacking.

A man who has tasted with profound enjoyment the pleasure of agreeable society will eat with a greater appetite than he who rode horseback for two hours. An amusing lecture is as useful for health as the exercise of the body.

No one may force anyone to be happy according to his manner of imagining the well-being of other men; instead, everyone may seek his happiness in the way that seems good to him as long as he does not infringe on the freedom of others to pursue a similar purpose, when such freedom may coexist with the freedom of every other man according to a possible and general law.

Deaths, births, and marriages, considering how much they are separately dependent on the freedom of the human will, should seem to be subject to no law according to which any calculation could be made beforehand of their amount; and yet the yearly registers of these events in great countries prove that they go on with as much conformity to the laws of nature as the oscillations of the weather.

For if phenomena are things by themselves, freedom cannot be saved. Nature in that case is the complete and sufficient cause determining every event, and its condition is always contained in that series of phenomena only which, together with their effect, are necessary under the law of nature.

But freedom is a mere Idea, the objective reality of which can in no wise be shown according to the laws of nature, and consequently not in any possible experience; and for this reason it can never be comprehended or understood, because we cannot support it by any sort of example or analogy.

The sublimity and intrinsic dignity of the command in duty are so much the more evident, the less the subjective impulses favor it and the more they oppose it, without being able in the slightest degree to weaken the obligation of the law or to diminish its validity.

Have patience awhile; slanders are not long-lived. Truth is the child of time; erelong she shall appear to vindicate thee.

Space and time are the framework within which the mind is constrained to construct its experience of reality.

Out of the crooked timber of humanity, no straight thing was ever made.

A society that is not willing to demand a life of somebody who has taken somebody else's life is simply immoral.