Introduction to Ethics

TAMUCC Introduction to Ethics Don Berkich
Philosophy Kantian Ethical Theory Notes

The best way to understand Kantian Ethical Theory (KET) is to grasp Kant's objections to UET. Kant proposed that there are two kinds of Oughts, which are distinguished by their logical form. Hypothetical Oughts are in the form of a conditional, while Categorical Oughts are not--they are unconditional.

Examples of Hypothetical Oughts:

  • If you would maximize utility, then harvest Lisa's organs.
  • If you would maximize utility, then keep your promise.

But of course one may not care about maximizing utility. Hypthetical Oughts are binding only to the extent that we have the appropriate desires. In the absence of appropriate desire, Hypothetical Oughts are not binding; we need not perform the action indicated by the Hypothetical Ought.

For Kant, moral duties are absolutely binding. Moral Oughts must be absolute. Categorical Oughts are unconditional.

Examples of Categorical Oughts:

  • Keep your promises.
  • Don't lie.

Categorical Oughts are absolutely binding. They are exceptionless. It follows for Kant that only Categorical Oughts can count as moral duties.

Kant argued that Categorical Oughts (moral duties) could be derived from a principle, which he called the Categorical Imperative. He gave three versions of the Categorical Imperative, but he thought that they were all equivalent. Here are two.

The Categorical Imperative

First Formulation


Act only according to that maxim by which you can at the same time will that it should become universal law.


Second Formulation


Act so that you treat humanity, whether in your own person or in that of another, always as an end and never as a means only.

The Second Formulation will prove to be useful when we consider specific issues in Medical Ethics. The First Formulation, on the other hand, is the basis for Kantian Deductions, which is how particular moral (absolute) duties are implied by KET.

Students sometimes make the mistake of thinking that the First Formulation of the Categorical Imperative is but a badly worded version of the Biblical "Golden Rule"--Do unto others as you would have them do unto you. Nothing could be further from the truth.

The Golden Rule, as Kant well knew, is a deeply misguided ethical principle. To see this, consider the following somewhat salacious example.

The Horny Martin Example

Suppose that Martin is 20 year-old college student. Suppose further that Martin has never been out on a date. The woman of his dreams finally agrees to go out with him. So Martin gets all dressed up and takes her out to a nice dinner, after which they drive up to Lookout Point. And...


Martin does unto others as he would have done unto himself,


with disastrous consequences.

Because the same result cannot be obtained by application of the Categorical Imperative, it follows that the Golden Rule and the Categorical Imperative are not extensionally equivalent.

Kant was not without his critics, however, and KET in particular has been challenged on Reflective Equilibrium grounds. The most famous such challenge is called the Case of the Inquiring Murderer.

The Case of the Inquiring Murderer

Suppose that Susan lives next door to Theresa and her abusive husband, Ulrich. Lately, the violence in Theresa and Ulrich's home has escalated. Theresa has even told Susan that Ulrich sometimes threatens to kill her. Late one evening, Susan gets a knock on the door. It's Theresa. Her face is bloodied and she's obviously terrified. Slamming the door shut and pushing past Susan, Theresa runs up the stairs to hide in Susan's bedroom. Before Susan has a chance to think, another knock comes at the door. Susan opens it, and sees Ulrich standing there, face flushed, breathing heavily. He asks, "Do you know where Susan is?"


What should Susan do?

  1 If KET is true, then Susan should tell the truth.  
  2 Susan should not tell the truth.  
3 KET is not true. 1&2

You may wonder, why on earth would KET imply that Susan should tell the truth, and thereby enable Theresa's murder? Remember from the example Kantian Deduction that everyone has the absolute duty to not lie. Hence premise (1) is true.

Of course, pretheoretically--i.e., judging solely by common moral intuition--whatever Susan does, she must not enable Theresa's murder. Hence she should not tell the truth.

Kantians, those who think that KET is true, have an answer to the Case of the Inquiring Murderer which you may or may not find plausible. They argue that the absolute duty to not lie is neither equivalent to, nor does it imply, the absolute duty to tell the truth. They say, for instance, that Susan can avoid lying and avoid enabling Theresa's murder merely by refraining to speak. Of course, you might imagine some problems with this response.

Because there are responses to the Case of the Inquiring Murderer, we conclude that KET arguably passes Reflective Equilibrium.