Sexual Desire and the Importance of Marriage in Kant's Philosophy of Law

• Date: 01 September 2014
• Author: Thomas Mertens
• Published date: 01 September 2014
• DOI: http://doi.org/10.1111/raju.12048

Sexual Desire and the Importance of

Marriage in Kant’s Philosophy of Law

THOMAS MERTENS

Abstract. In his moral writings, Kant states that moral duty cannot be derived from

“the special characteristics of human nature.” This statement is untenable if one

takes seriously Kant’s moral views on sexual desire. Instead close study reveals that

considerations based on both morality and nature play a role here. The combination

of these two elements leads to inconsistencies and difficulties in Kant’s under-

standing of sexual desire, but they enable us to better understand the importance

Kant attributes to marriage within his philosophy of law.

1. Introduction

In his Groundwork for the Metaphysics of Morals, Kant is clear that moral duty cannot

be derived from “the special characteristics of human nature.” The unconditional

character of the moral law holds for all rational creatures and whatever is derived

“from the special predisposition of humanity, from certain feelings and propen-

sities” can only supply a personal maxim and not a law: “It can give us a subjective

principle––one on which we have a propensity and inclination to act––but not an

objective one” on which we ought to act. This implies that practical philosophy, so

Kant continues, finds itself in a “precarious position” as it cannot be based on

anything in heaven or on earth. Morality, in other words, cannot be based on the

word of God or on the precepts of (“tutelary”) nature, but must find its origin in

the “sovereign authority” of reason alone. Mixing morality with anything that is

empirical would be highly “injurious to the purity of morals.” Practical philosophy

is therefore solely concerned with what ought to happen and not with what

happens; “reason thus entirely by itself determines conduct” and it does so a priori

(Kant 1911, 425–7).

Kant’s view on morality in the later Critique of Practical Reason does not differ.

Here, he confirms that nature has no role to play in moral duty. Moral will is

defined as a will that is determined solely by the “lawgiving form of its maxims.”

Since this form of law can be represented by reason alone, such moral determina-

tion of the will is completely “distinct from all the determining grounds of events

in nature in accordance with the law of causality.” In another passage, Kant

emphasizes that the will becomes a pathological will and thus deviates from the

requirement of morality, i.e., autonomy, as soon as it depends on a “natural law of

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Ratio Juris. Vol. 27 No. 3 September 2014 (330–43)

© 2014 The Author. Ratio Juris © 2014 John Wiley& Sons Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main

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