The ethical theory of Immanual Kant, who wrote around the beginning of the nineteenth century, has greatly influenced subsequent philosophical and theological reflection on moral principles. Kant attempted to transpose into philosophical terms the traditional, Protestant moral outlook. The product of his effort was very heavily conditioned by his peculiar metaphysics and theory of knowledge, which almost no one today accepts. But this framework aside, Kant’s view of moral principles is not so much false as grossly inadequate. Hence, it is not treated in this chapter as a mistaken theory. Still, a brief treatment of Kant might help the reader to understand the relationship between his theory of morality and the one to be presented in the coming chapters.²³

Kant would reject all the theories of moral principles criticized in this chapter and also any view which would base morality on the effectiveness of actions for promoting human happiness. He thinks that any such theory would reduce morality to a mere technique and thus depersonalize human persons. He especially notices that if the rightness of an action depended upon its effectiveness in realizing limited objectives (a theory to be criticized in chapter six), then human freedom and thus morality itself would be impossible.

Kant assumes that the natural world is thoroughly deterministic; he thinks that all observable human acts, including inner thoughts and choices, are determined by natural, including psychological, laws. To ensure that this universal determinism will not preclude morality, Kant separates the moral self absolutely from the world of experience. Goodness, Kant thinks, is centered wholly in a good will—that is, in the uprightness of one’s attitude in choosing.

But what constitutes an upright attitude? Kant cannot answer this question except in terms of the inner standards of the rational work of the mind itself, for to go beyond these standards (even by taking psychological factors into account) would mean that something else was imposed upon the moral self. Such an imposition would not be a moral “ought” but a freedom-destroying “must.” Therefore, Kant says that the uprightness of moral attitude, good will, consists in acting for the purpose of doing what is morally right. In other words, our action is morally good only if it springs from a will bent on doing what we ought to do.

What ought we to do? Kant explains that whenever we act, our action implies a rule. Human action is meaningful with a meaning which our own intelligence puts into it. Implicit in the fact that we are acting intelligently there is the thought: “Since such-and-such is what I want to accomplish and the factors in the situation I am up against are so-and-so, an act like this is the appropriate thing for me to do.” Now, Kant says, if the rule we have in mind is consistent with itself and if it could fit into a system of rules that we could really want everyone to follow consistently, then actions shaped by the rule may be done. But if the rule we have in mind cannot meet this test, then it cannot reasonably be adopted, and action shaped by that rule ought not to be done and will not be done by a person of good will.

Kant believes that if human persons were only their reason, then they never could be unreasonable and so never would do anything immoral. But since persons also exist as objects in the world of experience, natural feelings can get the better of reason. Individuals act by a private rationale for action, which means that they are acting intelligently and deliberately in view of their actual desires. But reason could not approve their private rationale, for they would not be able to adopt it as a general rule for everyone to follow consistently. In this way immoral acts can be chosen. For instance, individuals can decide to lie when it is convenient to themselves, but could not want lying to be a general rule, for that would render affirming meaningless and so remove the very possibility of either lying or affirming truthfully. Hence, telling a lie as a matter of convenience is wrong; people who do this act intelligently but unreasonably, sanely but immorally.

Moral uprightness is essential to human goodness (see 5‑F); and the rightness of action is not settled by its efficiency in promoting human well-being (see 6‑F). But chapter seven, developing points to be outlined in chapter five, will explain that the ultimate principle of morality—that which makes for a good will—is much more inclusive of human good than Kant thought. The good will must be open to a continuing unfolding of human fulfillment in all the basic goods of persons—including life and health, skill in work and play, and knowledge of truth—not just to moral uprightness.

Moreover, chapter eight will show that there are eight basic requirements for right choices of which Kant’s consistency test is only one. There are more ways of acting unreasonably than he realized, and so his test for morality is too loose. One who is inclined to lie might not be able to want everyone to do the same whenever it is convenient. But attention to specific features of the situation usually will reveal factors which will provide a much narrower justification which will seem rationally acceptable. Kant himself points out that a general rule—for example, excluding suicide—might well not hold in situations in which individuals have special reasons for choosing to kill themselves.²⁴

There are other difficulties in Kant’s theory, including the supposition that human persons could not sin if they were pure spirits, free of the supposed determinism of the world of nature. Immorality also has roots in the ability of finite freedom to limit its own unfolding. Moreover, Kant’s effort to separate the world of freedom and morality from the world of nature and determinism ultimately is incoherent in itself and inconsistent with the unity of human action.²⁵