[As I begin this fourth part of my tutorial on Kant's ethical theory, I am forced to confront once more the fact that there is vastly more to be said than can be squeezed into even the most capacious tutorial. I shall try not to make too great a shambles of it.]
The core idea underlying Kant's analysis, about which we must be very clear, is the distinction between what we may call behavior and action. By behavior, I mean any physical movements [including speech, of course, as a physical movement of the larynx, etc.] that a human being exhibits. This is a tricky matter, because to be completely clear, we would have to decide whether we mean to include as behavior physical movements whose proper description makes essential reference to social meanings -- a bit of behavior such as giving a command, for example, or playing a game. But assuming that we can sort all that out, all behavior, on Kant's view, is causally determined. This follows directly from the Second Analogy teaching that to be real in the Realm of Appearances just is to stand in thoroughgoing causal relationship to what has gone before and what comes after. Because behavior is causally determined [and hence, Kant thinks, at least in theory totally predictable], it is morally neutral. A bit of human behavior cannot be characterized as either virtuous or vicious, good or bad. It simply is.
By action, on the other hand, I mean things done by agents [human or otherwise] in accordance with and because of reasons. [There is a very useful discussion of this distinction in an old book by the English philosopher R. G. Collingwood. See The Idea of History.] To act, according to Kant, is to be guided by reasons. Now, all reasons are in their logical structure general, not particular. [This is, of course, totally independent of whether they are good or bad reasons.] If I choose to do something for a reason, I implicitly commit myself to a subjectively general rule concerning all other cases that are like this one in the relevant ways. Kant calls such subjective rules maxims. It follows, on his view, that whenever we act, we do so in accordance with a maxim of action. Maxims, as we shall see, have the syntactic form of imperatives. Generally speaking, they are of the form: "Having as your goal or purpose G, do A."
Kant has the reputation of being a rather rigid and rigoristic moralist, very much an old school Puritanical prig. His teaching about maxims feeds into this stereotype. We can just imagine him, in every situation, pausing to ask himself, "What is the maxim of my action?" before doing anything at all. Not at all a swinger, let alone a Dionysian! Now, leaving to one side the fact that as a young man Kant had something of a reputation as a billiards player and bon vivant [no kidding], this reflects a fundamental misunderstanding of Kant's position. The point is that action, as opposed to behavior, is brought about by reasons rather than causes, and reasons, by their logical structure, are implicitly general, hence expressible in the form of maxims. Whether we pause sententiously to reflect on our reasons or act seemingly spontaneously, it remains true that insofar as we are acting, we are determining ourselves by reasons.
The central question of the Grundlegung, and for Kant of all moral philosophy, is whether there are any subjective maxims that all rational agents as such necessarily adopt as the rules of their action, simply in virtue of being rational agents. If there are, then those subjective maxims will be Objective Laws, binding on all rational agents regardless of their desires, sentiments, purposes, or other differentiating characteristics. If there is one such objective maxim from which all other objective maxims can be derived, then it will be The Moral Law. Its validity for us will be absolutely unconditional. That, in a nutshell, is what Kant is looking for in his moral philosophy. Anything less, in his view, does not deserve to be called moral philosophy at all.
If you are paying very close attention, it may occur to you that there is a really big problem here. Action takes place in the Realm of Appearance just as much as behavior does. Kant thinks, for example, that I am morally obligated to keep my promises, [more of this when we get to Section Two.] Now, a promise is a commitment made by one person to another person in the Realm of Appearance. The keeping [or breaking] of the promise also occurs in the Realm of Appearance. But since both the making and the keeping [or breaking] of the promise occur in the Realm of Appearance, they must be bits of behavior standing in thoroughgoing causal relation to everything else that happens. How on earth can the making of a promise be both a bit of behavior falling under universal causal laws and also an action undertaken in accordance with a maxim?
This is a simply huge problem, to which Kant devotes Section Three of the Grundlegung, and about which we shall have a very great deal to say.
A second point of information and clarification before we turn to the Three Propositions listed at the end of Part Three above. Because Kant is searching for rules of action that are binding on all rational agents as such, he conceives these rules as equally valid for non-human rational agents as well, which to him meant angels. [No snarky laughter please. If it makes you more comfortable, substitute aliens for angels] Our human condition -- our desire for pleasure, our aversion to pain, our mortality, our talents, sentiments, and predilections -- are all, from Kant's point of view, limitations or constraints on our nature as rational agents. Because of them, we have difficulty obeying The Moral Law, and find ourselves tempted to ignore it. Hence, we experience the Moral Law as an unconditional command, a Categorical Imperative. But it is at least possible that there should be rational agents unconstrained in this fashion, who recognize the objective validity of the Moral Law and abide by it simply because it is dictated by the universal principles of rationality. Such beings, Kant sometimes says, possess a Holy Will. They do not experience the Moral Law as a command, because they are not tempted to disobey it.
I find it interesting to compare this to the rules of formal logic, such as the Law of Contradiction. Mathematicians do not find themselves tempted to break the Law of Contradiction, secretly asserting "p and not p" when no one is looking, or wondering whether they can get away with an argument cast in one of the invalid syllogistic forms [Some A are B; some B are C; therefore Some A are C, for example.] If I may speak somewhat oddly, all of us, as mathematicians or logicians, have a holy will when it comes to reasoning in those disciplines. That is what it would be like to have a Holy Will in general.
By the way, there are lovely echoes here of the New Testament teaching that those reborn in Christ act naturally and spontaneously in conformity with the Law, as laid down in the Old Testament. Paul, of course, had some difficulty with several of the communities of followers of Jesus, who were doing some rather hinky things in the belief that, as reborn, they could do no wrong. He put a stop to that nonsense, I am happy to say. :)
Well, enough of throat clearing. Next part, I will address the three propositions directly.