Immanuel Kant was born on the 22nd of April, 1724, in Koenigsberg, Prussia (now Kaliningrad) and he died in the same city on the 12th of February, 1804. He was the fourth of nine children of his parents, Anna Regina, nee Reuter, and Johann Georg Kant, who both belonged to a Pietist branch of the Lutheran Church. When Immanuel Kant was eight, he entered the Piestist school, Friedrichskollegium, and remained there until 1740. As his parents were rather poor, he was dependent on financial support from Franz Albert Schultz (1692-1763), who had realized Kant’s immense talent, and who was headmaster of Kant’s school, professor of theology, and pupil of the famous German thinker of the Enlightenment, Christian Wolff (1697-1754).
Kant’s mother died in 1737 while he was still at school. From 1740 to 1746, the year his father died, Kant attended the University of Koenigsberg, studying philosophy, mathematics, natural sciences, and theology. After university, Kant earned his income as a private tutor for three families in the area of Koenigsberg. In 1755, he completed both his doctoral degree (Meditationum quarundam de igne succinta delineatio), as well as his habilitation (postdoctoral qualification) thesis (Principiorum primorum cognitionis metaphysicae nova dilucidatio).
In autumn 1755, he started to lecture at the University of Koenigsberg, and he had to finance himself from the fees he received from his students. The first time Kant had a salaried post was in 1766 as a librarian. Later, he was offered various professorships (e.g., Erlangen, Jena), which he turned down. He had to wait until 1770, when he was already forty-six, to become Professor of Logic and Metaphysics at the University of Koenigsberg. Eleven years later, Kant’s groundbreaking work, Kritik der reinen Vernunft (Critique of Pure Reason, 1781) was released. Schopenhauer named it the most important book ever written in Europe; however, initial response was not so favorable. As a consequence, he wrote the Prolegomena zu einer jeden künftigen Metaphysik which was published in 1783, the same year Kant bought himself a house. In 1785 Kant published the Grundlegung zur Metaphysik der Sitten; in 1787 the second edition of the Kritik der reinen Vernunft; in 1788, the Kritik der praktischen Vernunft; and in 1790, the Kritik der Urteilskraft. In 1793, Kant published Die Religion innerhalb der Grenzen der bloßen Vernunft, and it was this work that brought him into conflict with state authorities who wished to censor the work. A year later, he even wrote a second treatise on the philosophy of religion, Das Ende aller Dinge. As a consequence, he received an official letter accusing him of degrading Christianity and violating his duties as a teacher of youth. Even though he rejected the accusations, he agreed to refrain from writing further works about the philosophy of religion. Zum ewigen Frieden (1795), was Kant’s first book after his conflict with the authorities, and Die Metaphysik der Sitten was released in 1797. In Anthropologie in pragmatischer Hinsicht (1798), Kant published further material on the philosophy of religion since Friedrich Wilhem II, who was mainly responsible for the intolerant political atmosphere, had died. In October 1803, Kant became seriously ill. He died on the 12th of February, 1804.
Reason is a faculty for gaining knowledge. Kant wrote critiques of aspects of reason in order to find out what can be known. In doing so, he did not condemn reason, but rather determined its limits and sources. In the end, Kant rejected both empiricism and rationalism as appropriate theories of knowledge. There are purely rational ideas, but only as regulative principles, which means the ideas are connected to empirical data. Kant employed the following distinctions for his investigations: a priori/a posteriori; and analytic/ synthetic. A priori judgments are judgments independent of empirical experiences. A posteriori judgments are judgments founded in empirical experiences. Analytic judgments are judgments in which the predicate is already contained in the subject. Synthetic judgments are judgments in which the predicate is not contained in the subject but provides further information about it.
According to Kant, reason has both a material and a formal aspect. The formal aspect of reason is concerned with laws of thinking irrespective of any object, or general logic. General logic does not have any material aspect, as it solely rests on the necessary laws of thinking, deals with analytic, a priori judgments and is constituted from two aspects: Analytics, by means of which one positively tries to describe what understanding is capable of; and dialectics, by means of which one tries to rule out what reason is not able to achieve. Reason, in its narrower sense, is the highest source of knowledge, and it brings together whatever has already been structured by means of our understanding to establish the highest unity of thinking. Understanding also belongs to the higher sources of knowledge, but has a common root with sensibility. In addition, it is capable of structuring and linking anything given to it, and of establishing laws.
The material aspect of reason, on the other hand, deals with objects and the laws by which they interact. These laws are either laws of nature or laws of freedom. The science that deals with the laws of nature is called physics, whereas the science which deals with the laws of freedom is referred to as ethics. Both physics and ethics have empirical as well as nonempirical aspects. Whatever is nonempirical is rational and valid a priori, and all areas with which rational investigation is concerned are called types of metaphysics. In contrast to general logic, which deals with analytic, a priori judgments, metaphysics is supposed to help promote knowledge; it deals with synthetic, a priori judgments. However, it is far from obvious whether such judgments are possible. Consequently, Kant asked in his Kritik der reinen Vernunft, how are synthetic judgments a priori possible?
In his transcendental Elementarlehre (teaching of the main elements) Kant answered his question. His Elementarlehre addresses transcendental aesthetics, the transcendental logic wherein one can distinguish the transcendental analytic, and the transcendental dialectic. Aesthetics encloses the realm of the senses; analytic, the realm of understanding; and dialectic, the realm of reason. Within his transcendental aesthetics, Kant articulated that all sense perceptions must be structured within space and time as pure forms of intuition. Within his transcendental analytic, he explained that all thinking must be based upon the categories of, for example, causation. These are two of Kant’s most influential insights.
As both physics and ethics have rational aspects, there is a metaphysics of nature (physics deals with laws of nature) and a metaphysics of morals (the nonempirical aspect of ethics is referred to as moral philosophy). Theoretical reason deals with the metaphysics of nature. There is an analytics of pure theoretical reason which progresses from sensual experiences to notions and then to principles. Practical reason deals with the metaphysics of morals. There is an analytics of practical reason which progresses from the possibility of practical principles a priori to the notion of the objects of practical reason to moral feelings. Analytics is always concerned with notions (both of nature and of freedom) and principles. As a side note, rational investigations concerning the existence of God, the soul, and free will are impossible, according to Kant, as these things are beyond sense perceptions, and if one applies human forms of sensual perception (time and space) and human forms of thinking (e.g., causation) to things which are beyond sensual experience, one is led into contradictions.
Areas of study concerned with the empirical aspect of physics are now referred to as natural sciences. The empirical aspect of ethics is called practical anthropology. In practice, practical anthropology is the empirical investigation into all ethical questions. One must not forget that all laws, finally, are one aspect of reason. The formal aspect of reason deals with the laws of logic, and the material aspect of reason with laws of ethics and physics. One of the early Platonists, Xenokrates was the first to distinguish philosophy into categories of logic, ethics, and physics. This distinction played a vital role for Platonists and Stoics. Kant’s ethics owe a lot to Cicero’s, who in his final phase held a traditional Stoic position.
Kant distinguished between empirical and rational ethics. Empirical ethics is mostly practical anthropology; rational ethics, or the metaphysics of morals, is a rational investigation of moral law. The central aspect of the moral law is the will, as the will is responsible for one’s acts. The will constitutes character, which can be good, evil or holy. Ethics is concerned with the law of freedom, for without the realm of freedom, human choices would be determined solely by drives ornatural instincts as all animals are. Since human beings also belong to the realm of freedom or reason, reason decides when to act according to instinct and when to act according to reason. As humans belong to both realms, it is impossible not to be affected by one of them. All humans act sometimes according to reason, and sometimes according to instincts. Whether the will can be referred to as good or evil depends on which aspect is dominant. If a person acts mainly according to reason, then the will is good, if not, then it is evil. The moral law or the law of freedom has to be a law of duty, as individuals always have the inclination to act according to instinct and must force themselves to act according to reason. Once the inclination to act according to instincts is absent, the will is holy.
An individual acting according to reason bases actions on moral law which can be determined by the categorical imperative whose general formulation is, “Act so that the maxim may be capable of becoming a universal law for all rational beings” (Note: A maxim is the determining motive of the will). Each act that, if taken as a general rule, leads, for example, to the extinction of humanity, or to self-contradiction, does not fulfill the demands of this imperative. It is an imperative, as individuals are not inclined by instinct to act in accord with it. It is categorical, because it is unconditionally valid. Kant also mentions the hypothetical imperative that refers to all conditional connection without the end being a necessary one. If one wishes x, one has to do y, without y being a necessary motive for all rational beings. The moral law encloses the categorical imperative only.
To be able to base one’s actions on the moral law, or to be autonomous—which is the same—is the reason for a being to have dignity. All rational beings can base their acts on the moral law, and all human beings are rational. Therefore, all human beings have dignity. In the realm of purposes, everything either has a price, or dignity. That which has a price does have something that is its equivalent: It can be exchanged for something else. That which has dignity, on the other hand, is beyond all price; therefore, Kantian ethics exclude the possibility of calculations which are basic for a utilitarian. In utilitarianism, it can be justifiable for one person to kill another in order to save the life of a hundred, but Kantian ethics hold the dignity of one person as beyond all price.
As all rational beings have such dignity, one might wonder from what point a human being is rational. Rationality is linked to the capacity for making abstractions, forming concepts, and having a language. One might be tempted to infer that human beings achieve rationality around the age of three; however, Kant asserted that rationality is part of the immortal soul of a human being. Therefore, human beings already are in the possession of rationality before their bodies are able to express that capacity. Around the age of three, the body is able to express that capacity, but human beings are already rational from the time their bodies and souls are united. All these discussions are particularly relevant for the current bioethical debates, as dignity is a fundamental part of many current constitutions, and Kant’s concept of dignity is the most popular one.
- Guyer, P. (Ed.). (1992). The Cambridge companion to Kant. Cambridge, UK: Cambridge University Press.
- Jacobs, B., & Kain, P. (2003). Essays on Kant’s anthropology. Cambridge, UK: Cambridge University Press.
- Kant, I. (1900ff). Gesammelte schriften (Koeniglich Preussischen Akademie der Wissenschaften, ed.) Berlin: Akademie-Ausgabe.