Summary
Kant begins by surveying the different realms of philosophy. There are physics, ethics, and logic. All rational knowledge (using our intelligence instead of just our senses) is either material—about the natural world, or formal—about ideas. This second kind is called logic. Material philosophy is divided into two again—about specific objects, and the laws that determine them. These are the laws of nature, and the laws of freedom. The science of nature is called physics, the science of freedom is called ethics.
Logic has no empirical content, that is, its laws can’t be derived from observing the world. Natural and moral philosophy both have an empirical part, since nature is about finding the laws of the visible world, and moral philosophy about human will as it affects things in the world.
All philosophy based on experience is empirical. All philosophy based on a priori principles, or intellectual principles, is “pure philosophy.” When it is purely formal, it is called logic. When it studies things we can experience, it’s called metaphysics. There are in turn two kinds of metaphysics: the metaphysics of nature (natural objects, as determined by the laws of nature), and metaphysics of morals (of objects as determined by the human will.)
Kant sees his Groundwork as a preparation for a moral philosophy. He compares it to a division of labor: just as you have to figure out how to build something before you start to build it, he argues we must understanding how morals are even possible before constructing a moral philosophy. This initial work is what the Groundwork will do.
Kant believes that for a moral philosophy to be truly valid, it has to be cleansed of everything empirical. We have to clear our common understanding of duty and of laws, because for a moral law to be truly binding, it has to be universally necessary. Our common understanding of morality is filled with all sorts of fuzzy concepts and conventional wisdom that ends up misleading us.
For, say "never tell a lie" to be a truly valid moral law, it has to be explained by reason, not experience. We can use experience to come up with practical rules for ourselves or helpful suggestions; but it will never give us universal moral laws.
Therefore, moral philosophy has to be grounded in abstract reason, not in experience, though experience can help sharpen our rational judgment. Insofar as we rely principally on our experience, morals will be subject to corruption and prejudice.
For something to be good, Kant insists, it has not just to accord with a moral law, but to be done for the sake of the law. Otherwise, that conformity is just accidental. The same inner inclination that motivates us to do good can just easily incline us to do evil.
Without universal moral law, there can be no moral philosophy, only limited situational judgments. Kant distinguishes his philosophy from that of Christian Wolff’s, which he claims is more of a psychology that attempts to analyze the way that the human will acts in certain situations. Kant believes that a valid moral philosophy has to analyze the very possibility of moral judgments, and not just the human will and its motives as we experience them.
Kant positions this moral philosophy as the corollary to his Critique of Pure Reason, which asked how knowledge was possible at all. He thinks that explaining the possibility of moral will be an easier task than the one he set himself in the first Critique, because moral philosophy is concerned with experience, and so we can at least use experience as a corrective, whereas the first one is pure abstract logic, and so risks easily falling into error.
The task of the project itself will be to say how such a pure philosophy of morals can be brought into line with actual moral action, and by what rights that is possible.
Kant closes by explaining that he will proceed by beginning with common ideas of morality and trying to figure out how a supreme moral principle can be determined from there. From there, he will try to show how these moral principles condition our actions.
Analysis
The preface for the Groundwork for the Metaphysics of Morals is similar to many of the openings to Kant’s major works. When Kant is tackling a question, he usually begins by distinguishing philosophy from other sciences and forms of knowledge. These distinctions give us helpful insight into Kant’s larger project and philosophical concerns, and more importantly, let us put the questions he is facing in the larger context of what philosophy is, and what it means to practice philosophy.
What is immediately striking is that Kant considers morals as a branch of metaphysics, which, as he argued in The Critique of Pure Reason, is the science of gaining knowledge through abstract thinking. This is strange for two reasons. First, it means that, methodologically speaking, we will be using abstract reason and logic to make sense of very concrete and lived situations. Second, it means that morality is a science, like physics.
This claim is no less counterintuitive to the modern reader than it was to the reader of Kant’s time. A common person, with no interest in philosophy, would have seen morality as rooted in religion and the authority of the church, while an enlightened reader, familiar with David Hume and Rousseau, would have believed that morality was rooted in human emotion. Both philosophers deeply impacted Kant, and we can read the Groundwork as an argument against their claims, as we will see in the next chapter.
But it is also important to remember that Kant lived in Prussia, a monarchic theocracy. The striking absence of God as the source of all goodness marks him as a thinker of the Enlightenment, and would cause problems for him with the authorities at the end of his life.
