1
" ...[A]ll the elements which belong to the notion of happiness are altogether empirical, that is, they must be borrowed from experience, and nevertheless the idea of happiness requires an absolute whole, a maximum of welfare in my present and all future circumstances. Now it is impossible that the most clear-sighted and at the same time most powerful being (supposed finite) should frame to himself a definite conception of what he really wills in this. Does he will riches, how much anxiety, envy, and snares might he not thereby draw upon his shoulders? Does he will knowledge and discernment, perhaps it might prove to be only an eye so much the sharper to show him so much the more fearfully the evils that are now concealed from him and that cannot be avoided, or to impose more wants on his desires, which already give him concern enough. Would he have long life? Who guarantees to him that it would not be a long misery? Would he at least have health? How often has uneasiness of the body restrained from excesses into which perfect health would have allowed one to fall, and so on? In short, he is unable, on any principle, to determine with certainty what would make him truly happy; because to do so he would need to be omniscient. "
― Immanuel Kant , Groundwork of the Metaphysics of Morals
10
" In the physical constitution of an organized being, that is, a being adapted suitably to the purposes of life, we assume it as a fundamental principle that no organ for any purpose will be found but what is also the fittest and best adapted for that purpose. Now in a being which has reason and a will, if the proper object of nature were its conservation, its welfare, in a word, its happiness, then nature would have hit upon a very bad arrangement in selecting the reason of the creature to carry out this purpose. For all the actions which the creature has to perform with a view to this purpose, and the whole rule of its conduct, would be far more surely prescribed to it by instinct, and that end would have been attained thereby much more certainly that it ever can be by reason. Should reason have been communicated to this favored creature over and above, it must only have served it to contemplate the happy constitution of its nature, to admire it, to congratulate itself thereon, and to feel thankful for it to the beneficent cause, but not that it should subject its desires to that weak and delusive guidance, and meddle bunglingly with the purpose of nature. In a word, nature would have taken care that reason should not break forth into practical exercise, nor have the presumption, with its weak insight, to think out for itself the plan of happiness and the means of attaining it. Nature would not only have taken on herself the choice of the ends but also of the means, and with wise foresight would have entrusted both to instinct. "
― Immanuel Kant , Groundwork of the Metaphysics of Morals
13
" [A man] finds in himself a talent which with the help of some culture might make him a useful man in many respects. But he finds himself in comfortable circumstances and prefers to indulge in pleasure rather than to take pains in enlarging and improving his happy natural capacities. He asks, however, whether his maxim of neglect of his natural gifts, besides agreeing with his inclination to indulgence, agrees also with what is called duty. He sees then that a system of nature could indeed subsist with such a universal law, [where] men... let their talents rest and resolve to devote their lives merely to idleness, amusement, and propagation of their species - in a word, to enjoyment; but he cannot possibly will that this should be a universal law of nature, or be implanted in us as such by a natural instinct. For, as a rational being, he necessarily wills that his faculties be developed, since they serve him, and have been given him, for all sorts of possible purposes. "
― Immanuel Kant , Groundwork of the Metaphysics of Morals
19
" If now we attend to ourselves on occasion of any transgression of duty, we shall find that we in fact do not will that our maxim should be universal law, for that is impossible for us; on the contrary, we will that the opposite should remain a universal law, only we assume the liberty of making an exception in our own favor or (just for this time only) in favor of our inclination. Consequently, if we considered all cases from one and the same point of view, namely, that of reason, we should find a contradiction in our own will, namely, that a certain principle should be objectively necessary as a universal law, and yet subjectively should not be universal, but admit of exceptions. As, however, we at one moment regard our action from the point of view of a will wholly conformed to reason, and then again look at the same action from the point of view of a will affected by inclination, there is not really any contradiction, but an antagonism of inclination to the precept of reason, whereby the universality of the principle is changed into mere generality, so that the practical principle of reason shall meet the maxim half way. Now, although this cannot be justified in our own impartial judgement, yet it proves that we do really recognize the validity of the categorical imperative and (with all respect for it) only allow ourselves a few exceptions which we think unimportant and forced from us. "
― Immanuel Kant , Groundwork of the Metaphysics of Morals