The Metaphysics of Morals

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

Innocence is indeed a glorious thing, only, on the other hand, it is very sad that it cannot well maintain itself, and is easily seduced.

....Happiness is not an ideal of reason but of imagination, resting solely on empirical grounds, and it is vain to expect that these should define an action by which one could attain the totality of a series of consequences which is really endless.

What then is it which justifies virtue or the morally good disposition, in making such lofty claims? It is nothing less than the privilege it secures to the rational being of participating in the giving of universal laws, by which it qualifies him to be a member of a possible kingdom of ends, a privilege to which he was already destined by his own nature as being an end in himself, and on that account legislating in the kingdom of ends; free as regards all laws of physical nature, and obeying those only which he himself gives, and by which his maxims can belong to a system of universal law, to which at the same time he submits himself. For nothing has any worth except what the law assigns it.

Now I say: man and generally any rational being exists as an end in himself, not merely as a means to be arbitrarily used by this or that will, but in all his actions, whether they concern himself or other rational beings, must always be regarded at the same time as an end.

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.

For now we see that when we conceive ourselves as free we transfer ourselves into the world of understanding as members of it, and recognise the autonomy of the will with its consequence, morality; whereas, if we conceive ourselves as under obligation we consider ourselves as belonging to the world of sense, and at the same time to the world of understanding.

It is a remark which needs no subtle reflection to make, but which we may assume that even the commonest understanding can make, although it be after its fashion by an obscure discernment of judgment which it calls feeling, that all the 'ideas' that come to us involuntarily (as those of the senses) do not enable us to know objects otherwise than as they affect us; so that what they may be in themselves remains unknown to us, and consequently that as regards 'ideas' of this kind even with the closest attention and clearness that the understanding can apply to them, we can by them only attain to the knowledge of appearances, never to that of things in themselves.

Happiness is not an ideal of reason, but of imagination.