An introduction to Kant’s Categorical Imperative.

In 1755, Immanuel Kant (1724-1804) became a Privatdozent, or non-stipendiary lecturer, making a living by charging students for his lectures and giving private tuition. His students joked that he could cover for the entire philosophy faculty—which at the time included everything except the three “higher” faculties of theology, law, and medicine. He became a star lecturer, reputed for his wit, dry humour, and poker face.

When he lectured, Kant was, according to a contemporary account, “all things to all men.” He stood at a diminutive five foot two (1.57m), with blond hair, blue eyes, and rosy cheeks. Despite his slender build, flat and narrow chest, and “slight corkscrew twist”, he was described as attractive. According to his own account, his flat and narrow chest left “little room for the movement of the heart and lungs”, contributing to his delicate constitution, predisposition to hypochondria, and sedentary, regimented lifestyle.

Kant compensated for his physical frailties by being a sharp dresser. He took inspiration from nature for matching colours. Thus, in middle age, he often wore a yellow waistcoat with a brown tailcoat trimmed with gold braid. In public and in company, he sported a powdered wig, even after it had fallen out of fashion. As late as 1791, his friend and follower Joachim Christian Friedrich Schulz described him as having “the look of a good, honest watchmaker who has gone into retirement”.

From 1766, Kant derived a modest but regular income as sub-librarian of the university. From 1768 to 1777, he rented two rooms in the house of the publisher and bookseller Johann Jakob Kanter. In this period, his student Johann Gottfried Herder described him as “the most urbane fellow in the world”. He moved in the city’s most refined circles and often stayed out into the small hours.

Kant never considered himself quite rich enough to take a wife. He twice considered marriage, first to a “beautiful widow” and, much later, to a “pretty Westphalian girl”, but in each case prevaricated for so long that the ladies ended up marrying otherwise. Although he never married, Kant defended the institution of marriage, which he prosaically defined as “the union of two persons of different sexes for lifelong possession of each other’s sexual attributes”.

Kant’s Categorical Imperative

Kant is famous, among other things, for trying to put morality onto a rational basis, that is, for trying to make morality objective and “categorical” rather than subjective and arbitrary. His core ethical principle is the Categorical Imperative, according to which we should only obey those moral laws that we could consistently and rationally will as universal laws. This might be restated as, “Always act such that the maxim of your action can at the same time be upheld as a universal law.”

The Categorical Imperative is similar to the much older Golden Rule of the Bible and Indian Mahabharata, according to which we should treat others as we would ourselves wish to be treated. But whereas the Golden Rule is based on personal desire, which is subjective (I might, for example, be a masochist, or be willing to tolerate some mistreatment), the Categorical Imperative is based on reason, which is objective.

Hypothetical imperatives are practical rules for achieving a desired outcome, for example, “If you want to lose weight, you should watch what you eat.’ If you do not desire a particular outcome, you do not need to follow the rules. In this much, hypothetical imperatives are conditional and contingent. In contrast, Categorical Imperatives are universal moral commands that bind everyone regardless of their aims, for example, “Do not lie”, “Do not steal”, “Do not commit suicide”.

Hypothetical imperatives answer to the lower faculty of desire, which aims at pleasure. Categorical Imperatives answer to the higher faculty of will, which functions rationally and autonomously by following the laws which it legislates for itself, regardless of consequences or personal feelings. For Kant, true moral actions must be motivated by duty, not some desired outcome. Thus, Kantian ethics are sometimes described as deontological, or duty-based (Greek, deon, “duty”), and contrasted with consequentialism (for example, utilitarianism), which is outcome-based. For Kant, moral systems based on outcomes or desires operate on hypothetical imperatives, not true moral law.

Kant furnishes some examples to flesh out the bones of the Categorical Imperative. Imagine a person in financial need who borrows money and promises to pay it back, knowing full well that they never will. If this action were universalised, promises of repayment would no longer be believed and the practice of lending would end. Kant also points out that abusing the lender in this way reduces a dignified being with ends of his own to a mere means-to-an-end.

The universalizability formulation is only the first formulation the Categorical Imperative. The second formulation is the humanity formulation, or end-in-itself formulation: “Act always treating humanity, in yourself and others, as an end and never merely as a means.” 

When Is It Moral to Have Sex?

Kant’s rigid application of the Categorical Imperative led him to condemn many actions and behaviours that are no longer generally condemned, such as suicide out of world-weariness, homosexuality, and masturbation. He referred to homosexual acts and masturbation as “unnatural vices” on the basis that the natural purpose of sex and the reproductive organs is procreation. Marriage, he argued, is the only morally permissible context for sexual relations. But for those unable or unwilling to wait, sex is preferable to masturbation. Masturbation transgresses the natural order, sex, only the civil order.

What has aged a lot better is Kant’s insight that, during sex, one turns the other into an object of gratification, a means to an end rather than an end-in-himself or end-in-herself. This is only permissible if, in return, one makes oneself into an object of gratification for the benefit of the other. Marriage, on the other hand, is a unique union in which two people mutually surrender their bodies and selves to create a united whole.

For us, the take-home message is: Kant never had sex or even masturbated. 

Jokes aside, Kant grew into, and arguably remains, the supreme moral authority in the Western World. For better or worse, what he thought and how he thought remains part of our mental makeup.