Kant’s Ethics: A Guide to Moral Duty and Practical Reason
Introduction
In practical reason, ethics answers the question, “What should I do?” Its function, as identified by Kant, is to guide our behavior. While theoretical reason deals with knowledge and makes judgments about phenomena, practical reason issues imperatives or commands. Kant’s Critique of Pure Reason marked a turning point in the explanation of science, and his work on ethics was equally novel. He proposed a formal ethics, distinct from previous material ethical theories that defined a highest good (e.g., happiness, pleasure) and deemed actions good or bad based on their contribution to that end. Kant recognized that humans desire happiness, but argued that actions are not inherently good or bad. The only unqualified good is the good will, and actions derive their moral worth from the will behind them. We act morally when we act out of duty, understanding the necessity of acting with respect for the law.
Duty and the Categorical Imperative
Kant distinguishes actions contrary to duty from those in accordance with duty. Within the latter, some are performed for personal gain (e.g., money, pleasure), while others are done for duty. Duty is expressed as an imperative (e.g., “Do not overcharge,” “Be honest”). Kant differentiates hypothetical imperatives from categorical ones. Hypothetical imperatives depend on a desired outcome (e.g., “Don’t overcharge if you want to retain customers“). Categorical imperatives, on the other hand, oblige unconditionally and are the sole source of moral worth. A maxim (e.g., “Don’t overcharge”) can be either hypothetical or categorical depending on the motive. The moral law is expressed in the categorical imperative, which has three formulations. The first, “Act only according to that maxim whereby you can at the same time will that it should become a universal law,” reveals its formal nature. It doesn’t prescribe specific rules but dictates the form moral standards must take. The subject’s maxims should be universalizable, applicable to all rational beings.
Moral Autonomy
Kant critiques previous ethical theories as heteronomous because they rely on external factors. True morality requires autonomy, where the subject gives themselves the law. External influences (e.g., desires, constraints) compromise morality. For example, the desire for profit diminishes the moral value of not overcharging. Only when reason dictates duty independently does the action have moral merit.
The Postulates of Practical Reason
In Critique of Practical Reason, Kant argues that freedom of the will, immortality of the soul, and the existence of God are postulates of practical reason, necessary for morality. While Critique of Pure Reason showed the limits of metaphysics as a science and the impossibility of knowledge about the soul, world, and God, Kant doesn’t deny their existence. He simply asserts that they are not subjects of scientific knowledge. Practical reason, however, requires them. Freedom is necessary for moral action, as it allows us to overcome inclinations and desires. Immortality of the soul is required for the pursuit of virtue, which may not be attainable in a finite lifespan. God’s existence guarantees the link between virtue and happiness, ensuring that acting morally is ultimately worthwhile. God represents an ideal of perfection, where being and duty align. The highest good (the union of virtue and happiness) is achievable only if God exists.
Other Formulations of the Categorical Imperative
The other two formulations of the categorical imperative are: “Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end,” and “Act as if you were through your maxims a law-making member of a kingdom of ends.” These formulations emphasize the dignity of human beings as ends in themselves and the possibility of a community where individuals are treated as absolute values.