Kantian Ethics Explained: Immanuel Kant’s Life and Philosophy

Immanuel Kant (1724–1804) was an eighteenth-century German philosopher. As a crucial figure of the Enlightenment, he was both influenced by and contributed to a period in which human knowledge was rapidly expanding. He wrote about a wide number of subjects, but his most visible legacy is his work on ethics and metaphysics, a category in philosophy that deals with abstract concepts like time, being, and space.

The majority of Kant’s most famous and influential philosophical works weren’t published until he was past fifty years old.

• Early beginnings: Immanuel Kant was born in 1724 to a Prussian German family in Konigsberg (now Kaliningrad, Russia), East Prussia. His childhood household was strict and very religious, and he studied the Bible and Latin. Kant learned his lifelong habits of discipline as a child, and he soon applied them to areas of inquiry, such as the sciences, that would come into conflict with his spiritual beliefs. As a student, he was exposed to the work of Isaac Newton, Gottfried Leibniz, Christian Wolff, and other major figures.
• Chair of logic: Kant was quite active in his youth and even achieved a degree of notice for shorter publications on philosophy, including Observations on the Feeling of the Beautiful and the Sublime (1764). He also engaged with much of the natural science being practiced. He worked as a tutor before being appointed the chair of logic and metaphysics at the University of Konigsberg in 1770.
• Magnum opus: After his appointment to the University in 1770, he began work on The Critique of Pure Reason. This ten-year project, done mostly in solitude, was finally published in 1781.
• Later works: Kant kept writing and publishing at a steady pace. In subsequent works, he developed his critical philosophy, seeking a way to tie ideas together in a reasoned, coherent whole. He lived to the age of seventy-nine.
• Influence: It would be hard to find another modern Western philosopher whose influence was as deep and lasting as Immanuel Kant’s. Future figures such as John Stuart Mill, John Rawls, and Michel Foucault, as well as schools of thought such as utilitarianism, would take his ideas into account. He remains discussed today as a central subject of philosophy departments all over the world.

Kant’s philosophy is highly complex and wide-ranging. He sought to expand the relevance of his philosophical ideas, so that topics such as human nature, rightness, and moral duty, would be as certain as physics. One of the most consequential areas of his work is that of ethical theory. A break with the virtue ethics of Aristotle, his works on ethical theory represented a new way to think about rationality and morals.

1. 1. Knowledge: Deeply influenced by the work of David Hume, whose radical skepticism challenged the common-sense notion of causality, Kant sought to show how empiricism wasn’t enough to be the sole basis of knowledge. Human beings can intuit things, working from a synthesis of “a priori” knowledge and experience, and a proper appreciation of rationalism has to incorporate this. Although conceding Hume’s view on causation, he nevertheless was a realist like Rene Descartes or John Locke, believing there to be real things, but that humans’ “posteriori” sensible knowledge of them is necessarily incomplete.
2. 2. Kant’s categorical imperative: The categorical imperative was an essential part of Kant’s moral philosophy. He believed a categorical imperative is something that human beings ought to do, in every instance, regardless of their desire. He described it as “act according only to that maxim through which you can at the same time will that it become a universal law.” For Kant, this was a kind of practical philosophy since it served as a guide for people’s moral actions in life.
3. 3. Good will: Kant’s conception of good will meant that doing the right thing was the highest possible virtue. No matter the outcome or one’s self-interest, when one acts according to good will, they are behaving the correct way, and that this can be ascertained according to our rational faculties.
4. 4. The second formulation of the categorical imperative: The key to Kant’s second formulation is in always treating other humans as ends in themselves, not means. For Kant, this followed precisely from the first conception of good will, although the linkage remains a matter of debate and scholarly deliberation.
5. 5. Deontology: Kant broke from other philosophical traditions by insisting that the actions themselves held moral value and were not defined by their consequences, which is a distinctly deontological view. Other ethicists gave greater emphasis to end results, known as teleological or consequentialist ethics. For Kant’s moral philosophy, the rightness or wrongness of an act had to do with whether it was conducted in good will, which he viewed as a right end in itself.
6. 6. Duty: Kant’s views on ethics were further developed in his notion of duty. By acting out of duty, which might be in conflict with one’s desires or even one’s well-being, a person is using their rationality to choose the morally correct course of action. He distinguished this from acting in accordance with duty, where someone does the right thing but for reasons other than duty, such as empathy.

For Kant, only the rational choice of correct action has moral worth. He broke duty into two categories: perfect and imperfect duty.

• Perfect duties: Perfect duties are defined by the categorical imperative: We have a moral obligation to do them, for failing to fulfill a perfect duty would be a contradiction of the will. An example is telling the truth; rational agents must always tell the truth, and to fail to do so is to deny our rational knowledge of the universal goodness of truth.
• Imperfect duties: Imperfect duties are those which can be honored or not, depending on the circumstances. For Kant, an example is beneficence, which is good, but not always strictly necessary.

To get a sense of Kant’s contributions to the discipline, it can be helpful to approach them through the works he wrote over the course of his life.

1. 1. The Critique of Pure Reason (1781): A culmination of Kant’s views on metaphysics and epistemology, The Critique of Pure Reason was Kant’s magnum opus, although it received critical reviews.
2. 2. Prolegomena to any Future Metaphysics (1783): After the First Critique was poorly received, Kant sought to clarify his views in Prolegomena to any Future Metaphysics in 1783.
3. 3. Answer to the Question: What is Enlightenment? (1784): This essay marked a foray into the realm of political philosophy, where Kant asserted that greater acceptance of reason in decision-making would lead to inevitable social progress. Swiss philosopher Jean-Jacques Rousseau influenced Kant’s ideas on moral philosophy and society.
4. 4. Groundwork of the Metaphysics of Morals (1785): Kant’s first significant work on moral philosophy, this source of Kantian ethics, argues that moral law can be determined through rationalist means.
5. 5. The Metaphysical Foundations of Natural Science (1786): This publication significantly fleshed out Kant’s theory of physics. In it, he sought to define the laws of nature in terms consistent with his previous philosophical writings and observations of the natural world.
6. 6. The Critique of Practical Reason (1788): Kant further elaborates his theory of morality in The Critique of Practical Reason. He develops these ideas methodically, starting with the first formulation building upon the former. Here, he shows how rational beings can arrive at a system of laws based upon their own moral principles. He was working out his idea of the categorical imperative, which stated that humans’ awareness of universal law came from the ability to reason, and needed no empirical evidence from outside. This is different from physical needs or desires, which for Kant were hypothetical imperatives. This led to a view of the rational being as an end in itself, not a “mere means.” This work is also known as the second of Kant’s critiques.
7. 7. The Critique of Judgement (1790): Kant’s The Critique of Judgment applied his ideas to the study of aesthetics and teleology.
8. 8. Perpetual Peace: A Philosophical Sketch (1795): Kant argues it is possible to create a peaceful world order free from war via the cooperation of constitutional republics. Because of the universality of Kant’s moral theory, he postulated that it could be the final stage of world history, a utopian Kingdom of Ends, which could provide humanity with an ideal to seek.
9. 9. Anthropology From a Pragmatic Point of View (1798): In this publication, Kant wrote a summary of his ideas on anthropology, which he had lectured on for over two decades.

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