Journal of the Evangelical Philosophical Society, Vol. 8, 1985

Would Kant Tell a Lie?

Stephen M. Clinton

Address to the Evangelical Philosophical Society, 1985


This article will discuss three questions which arise in connection with the moral philosophy of Immanuel Kant.1

1. Why is it wrong to lie?

2. How is the principle regarding lying derived from the categorical imperative (CI)?

3. Is it always wrong to lie?

The second formulation of the CI is known as the End-in-Itself Formulation.

    1. Act in such a way that you always treat humanity, whether in your own person or in the person of any other, never simply as a means, but always at the same time as an end. (GMM, p. 429)

I. Discussion

First, the use of the word "act" and the phrase "treat humanity" put us in actual moral situations. Kant is stating an ethical principle which will be applicable to specific moral choices. Second, he is concerned with "humanity" in persons (oneself or others). This will be important for the application of the principles.

On a casual reading "humanity" refers to a set of objects--human beings--and we are asked to treat the members of this set as ends. There is some justification in this, for Kant seems to do it in some passages (GMM, 430, 436, 437). Hill (1980, 85) suggests that it is better to understand "humanity" as referring to a characteristic or set of characteristics in persons, which Kant also does (LE, 196-197; DV, 441). In this sense, humanity is contrasted with animality. Its distinguishing feature is the power to set ends (DV 392, 423). 2

The third point regards how we treat humanity as an end. Kant discusses various points (which are summarized in Hill's article pp. 89-90). The central point seems to be that we should always act toward others based on principles which we can will that they would act on if faced with an identical situation.

Fourth, (1) uses the word "always" twice. Both lead to the same point: We are always to treat humanity in persons as an end. This universalizes actions which will fall under the CI. If, for example, lying is wrong because it offends or mistreats the humanity of a person, then it is always wrong in such cases to lie. 3 Therefore we may form two subpoints of (1):

(1a) Actions which are wrong are any actions which violate the humanity of persons.

(1b) We ought never to do wrong actions.

With this brief survey of the EIF we can now see how the problem of lying is derived from the EIF. Lying, Kant maintains, is a form of untruth (specifically, a medacium, LE, 226) one practices against oneself (DV, 428). Therefore, not lying is a negative perfect duty to oneself (DV, 81-82). Kant says that lying is the "greatest violation of man's duty to himself merely as a moral being (to humanity in his own person)" (DV, 428).

The main point made here is:

(2) Lying is a violation of a duty to oneself because it offends the humanity in a person.

The latter point picks out the specific relation of lying to the EIF. It is a violation of the humanity in a person. This offends (1). Therefore, since Kant holds to (1), and since (1a) and (1b) are understood. by Kant as part of (1), and since (2) stipulates that lying offends humanity in persons (namely in the liar) by (2), (1a) and (1b), we ought never to lie. Conclusion: One ought (has a duty) not to lie.

The initial questions may now be answered.

1. Why is it wrong to lie? Because lying violates a duty one has to oneself never to offend the humanity in oneself.

2. How is the principle regarding lying derived from the CI? By establishing that lying offends humanity in a person as shown by the argument above, and showing that the EIF of the CI includes that one should never offend humanity in a person.

3. Is it always wrong to lie? Yes, because the EIF is a universalizable formula. We ought always to act to promote humanity as an end. Therefore we should never violate humanity as an end.

Other arguments against lying are found in Kant, based on a duty to others. In GMM a lying promise is seen as a violation of the humanity of others (422, 429). In LE lying is "an infringement on the rights of humanity" (227).

Therefore, in cases of lying, one violates humanity in oneself and the humanity of mankind in general (in the humanity of the person[s] lied to in particular). Since EIF is universal, all lying is wrong. This covers even cases of well-intentioned lies. Such lies are meant to bring about good and do not violate humanity in others (LE, 229). But they still violate humanity in oneself.

Therefore, "a lie is a lie, and is in itself instrinsically base whether it be told with good or bad intent" (LE, 229).

II. Would Kant Tell a Lie?

All of the preceding builds a strong case against lying. Is there a situation in which Kant allows, or advocates, lying? One would think not.

However, in Lectures on Ethics, under "Ethical Duties Towards Others: Truthfulness," Kant says that there are numerous situations in which telling a lie does not offend humanity in the one to whom the lie is told. His examples are: when being robbed, when being swindled, and when our words will be improperly used against us (226-229).

Lest this seem to open the door to lying, he points out that these situations still violate the main point of the prohibition against lying: It harms the humanity of the agent. He then adds that lying also violates the humanity of mankind in general. This last qualifier is easily understood, but it is unusual for Kant to generalize a characteristic of a person or all persons to an extent where it gains independent status [more or less like one of Plato’s forms].

The point is made. Kant would never commend lying (as he defines lying), because it violates the humanity of the agent and general humanity, which thus violates the EIF.  


1I will use the following abbreviations throughout the paper:

CI - Categorical Imperative

EIF - End In Itself Formulation of the CI

GMM - Groundwork of the Metaphysic of Morals

LE - Lectures on Ethics

DV - The Doctrine of Virtue

2See Hill's paper pp. 86-88 for a list of other features.

3For more discussion of this absolutizing, see Jussi Tenkku, Are Single Moral Rules Absolute in Kant's Ethics (1967) and T. Hill's review comments.


Hill, Thomas E., Jr. "Humanity as an End in Itself," Ethics 91 (Oct.,1980): 84-99.

Kant, Immanuel. The Doctrine of Virtue. Part II of The Metaphysic of Morals (originally published 1797). Translated by Mary Gregor. Philadelphia: University of Pennsylvania Press, 1964.

Groundwork of the Metaphysic of Morals. (Original publishing date not given). Translated and analyzed by H. J. Paton. New York: Harper Torchbooks, 1964.

Lectures on Ethics. Translated by Louis Infield. New York: Harper Torchbooks, 1963.