Kantian ethics is fundamentally committed to a radical critique of human social life, especially of social life in its “civilized” form. This critical tendency is not a mere ancillary feature or contingent concomitant of Kantian ethics. It conditions the fundamental conception of Kantian ethical theory.

The Kantian philosophy is no more than at best a half-secularized version of such a theocratic ethics, with “Reason” in the place of God. This does not amount to much more than a change of names.

Don’t children have the same rights to life and equal concern as adults? Don’t we have moral reasons to concern ourselves with the welfare of nonrational beings, such as animals? Mustn’t that status rest on some value independent of the rational nature in persons?
Kantian ethics must answer the last question in the negative, but it answers the other two in the affirmative. I think the right account of the moral status of nonrational living things and of human beings who lack personality in the strict sense can best be derived from Kantian principles, even though Kant himself did not worry about these questions as much as he should have, and some of the things he said about them do not seem to me entirely cogent, or to be the best account available to him.

Kantian ethic, or what passes for it today, has always seemed to me to be the height of arrogance and folly. Claiming always to behave according to the precepts of universal maxims is either totally inept or totally hypocritical; one can always find a maxim to justify whatever behavior one chooses. I could not count the times (for example, when I tell people I never vote in elections) that I have heard the objection: "But if everyone were to behave like you..." - to which I usually reply that this possibility seems to me so implausible that I do not feel obligated to take it into account.

Thus Kantian autonomy, once it is understood, will (and ought to) disappoint those shallow minds and immature souls who are attracted to the doctrine of autonomy for the wrong reasons. They were hoping for some radical individualist revolution in morality, in which paroxysms of human self-will overthrow the divine will’s numinous majesty (thereby replacing, as many such revolutions sadly do, one arbitrary and unjust tyranny with another and bringing to power merely a different mob of unprincipled scoundrels). The sober rationalism of Kantian ethics is equally incompatible with voluntarism in its theological and its Promethean forms.

in the field of ethics, of moral knowledge, it was approached by Kant with his principle of autonomy. This principle expresses his realization that we must not accept the command of an authority, however exalted, as the basis of ethics. For whenever we are faced with a command by an authority, it is for us to judge, critically, whether it is moral or immoral to obey. The authority may have power to enforce its commands, and we may be powerless to resist. But if we have the physical power of choice, then the ultimate responsibility remains with us. It is our own critical decision whether to obey a command; whether to submit to an authority.

Free will is as philosophical a question, in that sense, as there is. Kantian ethics should not represent itself as having a solution to it. If the problem of freedom is a philosophical open wound, then the right way to think about Kant’s utterly unacceptable theory of noumenal freedom is that it is the salt that philosophers have a professional obligation to rub in the wound so that they can’t forget about it.

There are two main reasons that Kant refuses to allow that sympathy or any other empirical sentiment or desire could constitute the foundation of morality. One is that no sentiment of this kind can yield the kinds of objective and universal principles that morality requires. They can approximate to this only by claiming a greater empirical uniformity in human nature than experience shows to be there. […] Kant’s other main reason for rejecting sympathy or love as the basis of morality involves his view of the empirical psychology of these feelings as they arise in us in our social condition, and especially in the “civilized” condition of modern European society.

The pure normative standpoint that Kant’s ethics tries to occupy, a standpoint in which we consider only the normatively relevant features of a possible world, abstracting strictly from the real world and the empirical accidents of concrete situations, is an expression of what Dewey called “the quest for certainty.” In an insecure world, weak humans struggle convulsively to reach some kind of stability; the a priori is an overcompensation in thought for experienced human weakness. This is one of the origins of Kant’s notorious rigidity, his authoritarian devotion to “principles,” and his tendency to promote local habits of thought to constituents of the absolute framework in which alone (purportedly) any coherent experience was possible; thus, Euclidean geometry is declared the a priori condition of human experience, and sadistic remnants of Puritanism become demands of pure practical reason. Classical liberalism rejected Kant’s practical philosophy, but perhaps this is not enough. Perhaps one should also reject the very idea of a pure normative standpoint.

This point is, in essence, the most important and overlooked one regarding the rationality of ethics. The traditional dispute between Kantians and sentimentalists rests on an assumption that to be rational, morality must be grounded on a priori principles of disinterested reason. This is false. If we understand what rationality means in an appropriately catholic way, we see that it it is a matter of providing reasons for belief and that the sources of these reasons are not confined to a priori principles of logical or scientific facts. Once we accept that, we can see that although the Kantian project of founding ethics on pure reason is doomed, reason is still at the very heart of morality.

Psychoanalysis is not science. But very few things are science. Nor is Kant's ethics a science, but it is a high-level reflection about the human being in his relation with the world, as is Freud's reflection. What seems curious is the scarce insistence about the fact that Kantian ethics is not science, while everyone seems so preoccupied with stressing the non-scientificity of psychoanalysis.

Kantian liberals thus avoid affirming a conception of the good by affirming instead the priority of the right, which depends in turn on a picture of the self given prior to its ends. But how plausible is this self-conception? Despite its powerful appeal, the image of the unencumbered self is flawed.

It may seem as if Kant was content with such a radically dualistic view of human action, but ultimately he was not. … What Kant is assuming here is that morality is not just a matter of making rightful or virtuous choices, but also requires us to put those choices into practice by attempting to realize the goals or ends that they entail in the arena of action, that is, nothing less than the realm of spatial, temporal, and causal nature in which we live and act.

Like Plato, Kant believed that human beings have a dual nature: part animal and part rational. The animal part of us follows the laws of nature, just as does a falling rock or a lion killing its prey. There is no morality in nature; there is only causality. But the rational part of us, Kant said, can follow a different kind of law: It can respect rules of conduct, and so people (but not lions) can be judged morally for the degree to which they respect the right rules. What might those rules be? Here Kant devised the cleverest trick in all moral philosophy. He reasoned that for moral rules to be laws, they had to be universally applicable. If gravity worked differently for men and women, or for Italians and Egyptians, we could not speak of it as a law. But rather than searching for rules to which all people would in fact agree (a difficult task, likely to produce only a few bland generalities), Kant turned the problem around and said that people should think about whether the rules guiding their own actions could reasonably be proposed as universal laws. If you are planning to break a promise that has become inconvenient, can you really propose a universal rule that states people ought to break promises that have become inconvenient? Endorsing such a rule would render all promises meaningless. Nor could you consistently will that people cheat, lie, steal, or in any other way deprive other people of their rights or their property, for such evils would surely come back to visit you. This simple test, which Kant called the “categorical imperative,” was extraordinarily powerful. It offered to make ethics a branch of applied logic, thereby giving it the sort of certainty that secular ethics, without recourse to a sacred book, had always found elusive.