Kantianism refers to a line of thought that is broadly based on the philosophy of Immanuel Kant. The term can also refer directly to Kant’s own philosophy (see the article on Kant).


The revolutionary impact of Kant’s critical method on western thought has been such that practically every thinker in the last two hundred years has been affected by it to some extent. In that sense, all philosophers in that period could be said to come under the general umbrella of Kantianism, even those who oppose Kant’s conclusions, sometimes vehemently. Practically speaking, the term Kantianism refers to the thought of Kant and those immediate followers who remained within the general framework of his system. It may also be used to describe an orientation of thought of later thinkers who have taken over key elements from Kant’s philosophy. The renewal of Kantianism towards the end of the nineteenth century is usually referred to as Neo-Kantianism. The general epistemological position of Kantianism is that knowledge comes about through a synthesis performed by the subject. In ethics, Kantianism is synonymous with the deontological position expressed by the notion of the categorical imperative. The term Kantianism, or Kantian, is still often used to describe contemporary positions in philosophy of mind, epistemology, and ethics.

Origins of Kantianism

Immanuel Kant’s critical philosophy represents one of the major turning points in the history of western thought. Kant’s immediate predecessors, the great German philosopher Gottfried Leibniz and the systematizer of his thought, Christian Wolff had proposed an ambitious metaphysical system. Like René Descrates and others before them, they had sought to replace the religious dogma inherited from the middle ages by a rationalist deduction of ultimate truths about God, the human condition, and the universe. At the same time, in England the movement of British Empiricism, culminating with the philosophy of David Hume, had moved into the exactly opposite direction, that of skepticism towards any claim to knowledge about ultimate things, and an approach to knowledge based almost entirely on experience. Cause and effect, in that view, was not an absolute law but a simple habit of thinking based on repeated observation.

At a time when science was experiencing great progress based on the Newtonian revolution, a double question was thus raised: First, was the validity of scientific conclusion unquestionable, or was the scientific method a mere approximation for practical purposes? Even more importantly, was it possible to reach certain knowledge about transcending reality and ultimate things, given the contradictory claims of existing metaphysical systems, and in spite of the challenge of skepticism?

Principles of Kantianism

Kant offered a bold answer to the questions in his critical philosophy, known as a synthesis between Leibniz’s rationalism and Hume’s skepticism. Kant himself spoke of his “Copernican Revolution,” because his philosophy moved away from claims (of whatever kind) about an objectively given reality to an investigation of the human mind’s subjective processes. The conclusion that certainty was possible only to the extent that one could prove the validity of the subject’s mental processes would remain the permanent trademark of Kantianism.

In his first major work, the groundbreaking Critique of Pure Reason (1781; 1787), Kant would make the distinction between phenomena and noumena, the former referring to the unknowable nature of things-in-themselves and the latter to the way they appear to observers through the mediums of space and time (the forms of human intuition) and the categories of our mind, such as causality, identity, and substance. In other words, for Kant, observers only know things as they appear to them in space-time and the way the mind synthesizes them as concepts according to basic rules of thinking (the categories). These rules are the way people automatically think, thus they are a priori, that is, independent from experience. However, there is no guarantee whatsoever that intuition and thinking correspond to an objective reality. Entities that do not correspond to phenomena in space-time, so-called transcendent notions, including that of God, cannot be the object of any theoretical knowledge. For Kant, seeking to know them theoretically can only result in empty speculation. On the other hand, scientific knowledge arrived at by the proper use of the categories of the mind based on intuition in time and space yields to reliable knowledge, but only in terms of phenomenal knowledge about the world as it appears to humans. Reaching so-called “apodictic” certainty within the bounds of reason’s legitimate application, making philosophy into a science was Kant’s stated goal.

This conclusion led to what has become known as Kant’s agnosticism, the conviction that one cannot know with certainty what is related to ultimate issues. However, Kant himself saw his position as completely different from Hume’s skepticism. For him, it was important to realize that a theoretical knowledge about God comparable to scientific knowledge about the world was an illusion entertained by earlier metaphysics. Yet, there is an explanation as to why people seek to apply categories beyond experience, namely, why metaphysics is a natural human disposition. Why? Because of the very nature of human reason, which seeks to totally unify all reality into a systematic whole, thus resulting in notions such as "God" and "the eternal soul." Kant himself was firmly convinced of the existence of the noumenal realm, including God, and simply believed that certainty in these matters had to be arrived at in different ways. In his own words, reason had to make place for faith.

History of Kantianism


The impact of Kant’s critical method was comparable to that of Plato introducing his theory of ideas some 2000 years ago. It changed everything in philosophy. Only very few thinkers and schools of thought (such as the much later Neo-Thomism) would seriously challenge the new starting point created by Kant. Nevertheless, Kant’s thought left open a whole series of new questions about its consequences. Kant spent the remaining part of his life addressing these questions to arrive at a comprehensive view of life, but he did not succeed in providing responses that would satisfy his various followers. Instead, new schools of thought grounded in various aspects of Kant’s overall vision would appear in the ensuing years. Much of what determined these responses had to do with the way Kant’s own vision was understood, and this remains true to this day.

As was the case with Plato, Kant’s immediate successor soon departed from his perspective, while retaining the starting point of his thought. Plato was succeeded by Aristotle, whose system in many ways contradicts Plato’s while adopting many of his basic premises. Only centuries later did a reaction against Aristotle and other philosophies lead to a renewal of Platonic thought, Neo-Platonism in its different forms. In the case of Kant, with the acceleration of history, it took only decades before there was a reaction to the intervening systems (German Idealism and Positivism) and the emergence of various types of Neo-Kantianism.

Early Kantianism: A brief overview

The period of early Kantianism comprises the period stretching roughly from the last decade of the eighteenth century, when Kant had completed his main works, to 1830 (Hegel passed away in 1831).

At the end of the eighteenth century, Kant’s figure was so dominant that no thinkers of real magnitude emerged to form a Kantian school as such. First-rank thinkers who followed Kant immediately in Germany, while relying on some of his key premises, developed systems of thought that considerably departed from Kant’s own conclusions, thus forming so-called German Idealism. They include Fichte, Schelling, and Hegel. Later, Schopenhauer would propose his own system in contradiction to the German Idealists, claiming to be the rightful heir to Kant. Schleiermacher, the founder of modern theology, was also strongly indebted to Kant’s insights. None of these thinkers, however, can really be considered Kantians, as their conclusions widely differ from Kant’s own.

Several philosophers who where contemporaries of Kant or lived shortly after him deserve to be mentioned because, without slavishly following their mentor’s way, they attempted to respond to issues left open by the Kantian system by offering specific improvements within Kant’s general perspective. They include Karl L. Reinhold (who helped disseminate Kant’s thought), G.E. Schulze, Salomon Maimon, and Jakob S. Beck. More important, however, are Friedrich Heinrich Jacobi (1749-1832) and especially Moses Mendelssohn (1729-1786), both of whom closely interacted with Kant, often critically but with respect, while maintaining their own perspectives. Jakob Friedrich Fries (1773-1843) forms an exception in that he tried to incorporate an intuitive element into Kant’s thought. He is perhaps the most significant among Kant’s immediate successors who did not break with his basic premises but tried to improve his system.

Much later, past Neo-Kantianism, philosophers like Edmund Husserl, the founder of phenomenology, the existentialist Martin Heidegger and representatives of postmodernism would reject much if not most of Kant’s conclusions, while recognizing their considerable indebtedness to his breakthrough.

The two, three, or four realms of Kantianism

Kantianism is usually divided and subdivided into a number of types and categories, such as metaphysical, epistemological, ethical, and psychological Kantianism, based on the aspect of Kant’s thought that has been stressed by any of his numerous successors, especially in Neo-Kantianism, where this has led to the emergence of various schools. For a systematic assessment of Kantianism, it might, however, be more useful to follow Kant’s own “course of action” after writing his first Critique. A discussion on later Kantian schools can be found in the article on Neo-Kantianism.

Pure theoretical reason

The first Critique (Critique of pure reason) has a clear epistemological starting point. In Kant’s own words: "What can we know?" But it eventually leads back to the original question about being, the ontological question of metaphysics: What is the ultimate nature of things? This is the question that had plagued Kant all along, as it had his predecessors. After concluding that theoretical knowledge on this level was impossible (against his hopes), Kant went on to seek how this realm of ultimate reality could be grasped otherwise.

Much of the early criticism leveled against Kant pertains to the perceived inconsistencies of the main items of his philosophy: The noumenon or thing-in-itself, and the transcendental Ego, the awareness of “I” prior to any experience. Jacobi was the first to note that Kant appeared to consider the noumenon as the cause of phenomena, while at the same time considering causality as a category pertaining to the phenomenal world, thus making a cause and effect relationship between noumena and phenomena inapplicable. How Kant could see the noumenon as the “ground” of phenomena (he never spoke of causality) and how he could even justify his belief in the reality of a noumenal world behind phenomena has remained a hot topic of debate to the present day.

Fichte, who seemed destined to become Kant’s designated heir, insisted that the thing-in-itself was nothing else than the moral activity of the transcendental “I,” thus opening the way for the speculative approach of German Idealism. In his last, unpublished work, the Opus Postumum, Kant seems to have moved towards the idealist position. However, he never accepted Fichte’s conclusions, which meant that it is possible to directly grasp the thing-in-itself through “intellectual intuition.”

In the twentieth century, the young Paul Tillich based his philosophy of religion on Kant’s notion of the unconditioned horizon of the mind, a horizon transcending all conditioned (that is, relative) reality. Tillich’s position was highly unusual, since he did not seek a foundation for his notion of religion in Kant’s more religious writings, but in the first Critique’s conclusion that the mind inevitably aims at the limit of the unconditioned. In doing so, Tillich pioneered attempts to include secular attitudes under the umbrella of religion newly defined as “ultimate concern.”

Practical reason and ethics

Kant’s next step, in his Critique of Practical Reason and other writings, was to stress the certainties and duties of moral reason. For him, the ideas of God, freedom, and immortality, though not within the realm of theoretical reason, can and should be affirmed in virtue of practical reason. This led to the so-called moral proof for the existence of God: The ideas of justice and goodness entitle people to assume the existence of God, and no logical reason opposes the assumption, hence it is legitimate to make it. Furthermore, Kant held that reason required humans to act according to the categorical imperative, which he defined as the conscience’s call to act as one would expect others to act in the same situation, without any consideration for personal sympathies, let alone interests, or even outcome. All actions are performed in accordance with some underlying maxim or principle, and it is this that the moral worth of an action is judged according to. Simply put, the test is that one must universalize the maxim of one’s behavior. Kant's ethics are founded on his view of rationality as the ultimate good and his belief that all people are fundamentally rational beings.

Kant’s recourse to the moral argument as the only alternative to an impossible theoretical proof for the existence of God has always been widely criticized as unconvincing and even contrary to the spirit of Kant’s own critical method. The categorical imperative, however, was saluted by some as the philosophical expression of human conscience. Twentieth century theologian Emil Brunner has called it, “the penitent attitude in the language of the philosopher” and Karl Barth had a similarly positive view. Many others have looked at Kant’s deontological ethics as a manifestation of empty formalism remote from practical reality. The notion of absolute duty without a specific content has even been said to have negatively affected the psyche of the German people. To this day, Kant’s deontological ethics have remained as one of the key positions in ethics, alongside British utilitarianism and Aristotelian ethics of virtue. Few, however, would retain Kant’s views in their original strictness and many Kantians have sought to amend Kant’s position to make them more acceptable to the modern mind (for example, by trying to avoid such unacceptable conclusion as that of having to betray a persecuted fugitive by telling the truth to his potential killers).

Generally, those who see Kant’s philosophy as consisting of two parts, a theoretical one and a practical or ethical one, without a proper interaction between the two, have a negative, or at least critical, view of his overall achievement.

Aesthetics and teleology

In his third Critique, the Critique of Judgment, Kant intended to create a bridge between theoretical reason and practical reason by means of reflective judgment. Kant compares aesthetic judgment with the teleological judgment based on the apparent harmony within nature. The harmonious beauty of the universe seems to imply the presence of a Designer, just as the beauty of an artwork does. In Kant’s eyes, this goes further than the mere evidence from moral reasoning, but it still does not amount to theoretical certainty.

Kant’s third Critique has often been ignored as an inconsistent and failed attempt, eventually leading back to his philosophy’s dichotomy between theory and ethics, since it does not change the fact that theoretical, scientific truth about God is impossible. The reflective judgment based on an aesthetic perception of the universe merely has a “regulative” function, according to Kant. Still, this work has had an impact, with some considering it a bona fide, third component of Kant’s system, that of aesthetics. In Kant’s triad, it answers the question of what one can hope for. It is interesting to note that Moses Mendelssohn seems to have anticipated some of Kant’s views on aesthetics and teleology.

In his 1911 Philosophy of "As If" (Philosophie des Als Ob), German philosopher Hans Vaihinger based his pragmatic development of Kantianism on Kant’s insistence, in his third Critique, that everything in the world happens “as if” there was a conscious Creator and planner behind phenomena. Jakob Friedrich Fries (1773-1843) suggested that aesthetic sense (Ahndung) allowed us to directly perceive or intuit the reality of the supernatural, and that Kant’s mistake had been to try to explain what merely needed to be shown. For Fries, the capacity to appreciate beauty was a sign of moral excellence and thus related to the capacity to perceive the divine. Fries’s conclusions can be found in his 1805, Knowledge, Belief, and Aesthetic Sense (Wissen, Glaube, und Ahndung).

Rudolf Otto (1869-1937) based his groundbreaking notion of the “numinous” on Kant’s notion of the sublime. Compared to regular beauty, the sublime elicits a feeling of awe in addition to aesthetic appreciation. For Otto, the numinous, that is, the non-rational sense for the divine, is closely related to the sublime’s sense of awe and even fear of the supernatural (added to a mysterious sense of attraction). The thoughts of Fries and Otto can be seen as an extension of Kant’s third Critique. Recently, Kant’s influence on Fries, Otto, and philosophy of religion via his third Critique has been positively evaluated by Harvard Divinity School’s Adina Davidovich in her, Religion As a Province of Meaning: The Kantian Foundations of Modern Theology (1994). Based on Kant’s third Critique especially, it is possible to speak of Kant’s inductive method in metaphysics, that of reaching tentative conclusions based on given data.

Kant's positions in teleology were neglected by scientists for many years because in their minds they were associated with vitalist views of evolution. Their gradual rehabilitation recently is evident in teleonomy which bears a number of features, such as the description of organisms, that are reminiscent of the Kantian conception of final causes as essentially recursive in nature.

Rational religion

The fourth and perhaps most disputed aspect of Kant’s system is the properly religious element. For decades, Kant has been accused of being a purely rationalist deist opposed to all forms of established religion and devoid of any genuinely religious sense or interest. It has repeatedly been said that, for Kant, religion merely amounted to ethics.

In his only major work on religion, Religion Within the Limits of Reason Alone (1793), written towards the end of his life, Kant offers an explicit appreciation of the role religion should play in human society. Even those with a positive appreciation of Kant’s religious content have often dismissed that particular work based on its very title, suggestion a reduction of religion to mere reason. A careful reading of this work does not fully vindicate that interpretation, however, and neither does it support the opinion that the book was merely meant to appease the government’s suspicion that Kant was anti-Christian. The opposite charge that the book is an expression of Kant’s anticlericalism is also difficult to explain based on the text. Kant does indicate that the core of religion is and should be rational, but this also amounts to a considerable stretching of the meaning of “rational.” In his Kant (1957), contemporary German philosopher Karl Jaspers expresses this when stating that, in religion, reason perceives a realm that forms its own limit, a realm that reason wants to attract to its own light. Kant also stresses that the unexplainable presence of evil in the human soul, a presence that makes it impossible to respond to the commands of the moral imperative also present in our soul, makes it reasonable to expect supernatural help.

Long ignored, Kant’s only properly theological book has received renewed and positive attention in recent years as evidenced by Kant and the New Philosophy of Religion (2006), edited by Chris Firestone and Stephen Palmquist. From the perspective of such Kantian scholars, the apprehension of the religious realm forms a genuine fourth aspect of Kant’s work, one where the aging philosophers sought to stretch his system to its utmost limits in order to attain what had been the fundamental goal from the beginning. By giving the word reason a sense that goes beyond the ordinary sense of mere logical reasoning, Kant offers an alternative to thinkers that emphasize the role of the irrational as a counterpart to reason, with the result of creating a dichotomy between the two. Similarly, Fries would state that faith as the understanding of the divine represents the highest function of reason.

Political philosophy

In addition to the four main realms of his thought, Kant’s “philosophical sketch on Perpetual Peace” written in high age (1995), is also widely credited to have anticipated and inspired the creation of the League of Nations and later the United Nations.

In political philosophy Kant has had wide and increasing influence with the major political philosopher of the late twentieth century, John Rawls drawing heavily on his inspiration in setting out the basis for a liberal view of political institutions. The nature of Rawls' use of Kant has engendered serious controversy but has demonstrated the vitality of Kantian considerations across a wider range of questions than was once thought plausible.


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External links

All links retrieved May 29, 2014.

General philosophy sources


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