Unit 3: Overview

Both of our previous thinkers grounded morality in what we are. For Aristotle, the good life is the life that fulfills the distinctive function of a human being. For Aquinas, the natural law is what reason discovers about the kind of creatures God made us to be. In both cases, facts about human nature do the moral work.

Kant is going to reject this strategy completely. In his view, building ethics on human nature makes morality contingent: if human nature were different, morality would be different. Kant thinks genuine moral principles cannot depend on what kind of creatures happen to exist. They must be binding on every rational being as such, from us to an angel to a Martian, if any such exists. That means moral principles have to come from reason alone.

The Groundwork for the Metaphysic of Morals is Kant's attempt to show what such a morality would look like and why we are bound by it. The book is short: around 40 pages of text, structured as a Preface and three sections. But it is one of the most difficult books you will read in this course, and it has shaped ethics more deeply than almost any other work since Aristotle.

The core idea is the categorical imperative: a moral principle that holds unconditionally, regardless of what we want or what consequences might follow. Kant argues that there is exactly one such principle at the foundation of morality, and he gives us several different formulations of it. The most famous: act only on a principle you could will to be a universal law. Another: never treat other people merely as means to your ends, but always also as ends in themselves.

Kant is not easy. His prose is dense, his vocabulary is technical, and he builds arguments in long chains where one misstep early makes later sections hard to follow. Students who come in expecting to read Kant the way they read a novel usually bounce off the text.

There is good news. The Groundwork is a short book, and its argument, though elaborate, is reasonably linear. If you read the first section carefully, the second and third become much more tractable. The edition we will use is a modern English translation by Jonathan Bennett, which renders Kant's German in the clearest English available without sacrificing the substance of the argument. Bennett marks his own explanatory additions with dots and brackets, so you can always see what is Kant and what is editorial help.

By the end of this unit, you should be able to:

• Explain why Kant rejects ethics grounded in human nature, human happiness, or the consequences of action.
• Define the good will and explain why Kant holds that it is the only unconditional good.
• Distinguish hypothetical from categorical imperatives and give examples of each.
• State the universalization formulation of the categorical imperative and apply it to a concrete case.
• State the humanity-as-end formulation of the categorical imperative and explain what it means to treat someone merely as a means.
• Explain the connection, in Kant's view, between freedom, autonomy, and the moral law.

All of our Kant reading comes from a single text: the Groundwork for the Metaphysic of Morals, in Jonathan Bennett's modern English translation. The full text runs about 40 pages and is free to read online.

• Kant, Groundwork for the Metaphysic of Morals (1785), translated by Jonathan Bennett

We will take the text in order, one section per lecture page.

• Preface and Chapter 1: common morality, the good will, duty (paired with the Good Will and Duty lecture)
• Chapter 2: hypothetical and categorical imperatives, the formulations (paired with the Categorical Imperative lecture)
• Chapter 3: freedom, autonomy, the two standpoints (paired with the Freedom and Autonomy lecture)

What you need to complete this unit

Work through each item in order.

• Read the lesson pages in this unit and watch the lecture videos on them
• Read the assigned text (see Readings above)
• Complete the reflection prompt
• Take the unit quiz