Immanuel Kant: The Critique of Pure Reason

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The article below was originally written as an undergraduate assignment for the Greek Open University in 2007, during a period when the author’s academic skills were still developing. Although the quality of this article does not match that of later examples of the same author’s work, it is written in a thorough manner and contains useful information for students and other readers with non-specialised knowledge; therefore, it has been proudly included on this website.

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Introduction

In the introduction to the second edition of his Critique of Pure Reason (1787, B30), Immanuel Kant (AD 1724-1804) notes: “So, I had to abolish Knowledge in order to secure a place for Faith”. In his thesis, Kant employs a critical approach that harmonises the coexistence of Theoretical and Practical Reason. Based on the above statement, this paper discusses Immanuel Kant's philosophical ideas regarding Reason and his contribution to the evolution of European philosophical thought during the transition from the Enlightenment to the 19th century. The paper is divided into four sections.

The first section discusses two of the most popular philosophical movements during the final phase of the Enlightenment, Rationalism and Empiricism, which impacted Immanuel Kant’s thoughts. The approaches of these schools led to two philosophical dead ends, which Kant acknowledged and sought to bridge. The second section presents a brief introduction to the division between Practical and Theoretical Reason, which was discussed in Kant’s volume Critique of Pure Reason. The third section examines the role of religious faith in Kant’s theoretical scheme, which was characterised by the disengagement between faith and knowledge. Still, Kant saw certain limitations in human knowledge; therefore, he noted the contribution of faith in the development of human morality. The final section presents a summary and some general conclusions on Kant’s approach.

Philosophical traditions before Immanuel Kant

Before Kant, the Enlightenment movement had already impacted contemporary philosophical thought and had established a new scientific tradition: the pursuit of knowledge through the observation of the empirical world. This shift occurred under the influence of Isaac Newton (AD 1643-1727), who saw the universe as an understandable entity. In metaphysics, the connection between experience and Reason, which was believed to be responsible for acquiring knowledge, sparked a debate that challenged Newton’s evidential approach (Molyvas 2001, 67).

At the end of the 18th century, metaphysics was dominated by two opposing movements: Rationalism, introduced by Benedict de Spinoza (AD 1632-1677) and Gottfried Wilhelm Leibniz (AD 1646–1716), and Empiricism, introduced by David Hume (AD 1711-1776). The main question set by contemporary metaphysics was whether human beings could achieve objective knowledge of the world. Leibniz argued that such objective knowledge was possible and could be independent of the observer’s perspective; however, the world contemporary scholars examined was deemed unreal. By contrast, Hume argued that the world, which used to be captured by the human senses, was indeed real; however, it was the human beings who were unable to build an objective knowledge of this world (Molyvas 2001, 67-8).

Kant realised that human experience was not enough to guide someone to knowledge. In that sense, his conclusion stood in opposition to the Empiricist approach. Although Kant recognised that knowledge is derived from human experience, he defined a natural force as the primary motive for acquiring knowledge. This force was named causality. Of course, Kant's acquisition of knowledge was subject to the limitations of human experience; therefore, knowledge had boundaries. Kant’s model of limited knowledge contrasted with Leibniz’s Rationalism, which stated that there were no constraints to empirical observation, and therefore, no limits to human knowledge. Further on, Kant saw that the analysis of the origins of knowledge, which was followed by other philosophical schools, was superficial; instead, he decided to analyse the content of empirical knowledge (Molyvas 2001, 67-8).

Kant realised that the existence or non-existence of objective knowledge in the universe was endangering human faith in God. Both Gottfried Leibniz (AD 1646–1716) and Christian Wolff (AD 1679-1754) adopted Rationalism from René Descartes (AD 1596-1650) and turned it into a rather extreme dogmatic system. They used to argue that a rational mind was so powerful that it could enable humans to understand and record every little detail of the surrounding world with absolute certainty. In this effort, God was unnecessary (Vallianos 2001, 30). As a result, Rationalists not only rejected the role of experience in the formation of knowledge, but also rejected God and His role in human understanding of His universe. On the Other hand, David Hume (AD 1711-1776) and the Empiricists considered scientific knowledge a plain belief of the human mind. As it had with any such belief, the Empiricists saw that scientific knowledge had only a psychological effect on humans; it was not supported by rational or empirical evidence; and, finally, it had no practical application (Vallianos 2001, 31-2). According to the same rationale, the Empiricists saw that the presence of God in the universe was another unsupported belief of the human mind, the importance of which was purely psychological.

Immanuel Kant attempted to bridge the Rationalist and Empiricist approaches by noting Reason's inability to comprehend transcendental concepts. By stating this inability, he managed to rescue religious faith, which at that time was threatened by scientific knowledge. The science of the 18th century was believed to be almighty, and under the influence of Empiricism, the justification of God and religious faith was being attributed to irrational motives. Kant decided to change this.

The division between Practical and Theoretical Reason

In the introduction to the second edition of his Critique of Pure Reason, Immanuel Kant defines the difference between Practical and Theoretical Reason and offers the researcher a methodological tool to harmonise the gap. Kant notes the limitations of human knowledge and acknowledges the connection between science and logic, which requires the foundation of scientific Reason (Kant 1999 [1787], 30). Scientific Reason is divided into Theoretical and Practical. Theoretical Reason defines the meaning of a studied concept, while Practical Reason contributes to the practical application of the same concept (Kant 1999 [1787], 39).

Pure Reason, whether Practical or Theoretical, is used for the definition of ‘a priori’ concepts (Kant 1999 [1787], 39). Kant’s ' a priori’ concepts or ' a priori’ categories are those which exist beforehand. They are tools implanted in the human intellect, which arrange the empirical data coming from the senses, and lead to the production of ' a priori’ knowledge in the form of synthesis. The causality by Kant, which is the human predisposition that determines the causal structure of human experience, is characterised as an ' a priori’ category (Vallianos 2001, 34).

Mathematics and physics are two areas of scientific knowledge which fall under Theoretical Reason. Both fields are described as real sciences, and their aim is to define their ' a priori’ concepts. In mathematics, ‘a priori’ concepts are the theorems, to which the scientist concludes after following a process of evidentiary reasoning. In physics, ‘a priori’ concepts are all the physical laws, which are recorded as natural principles and are empirically confirmed by experiment and observation (Kant 1999 [1787], 40-2). Metaphysics is another area of Theoretical Reason, although it cannot be defined as scientific. Metaphysics cannot produce ' a priori’ concepts, as any conclusions are neither tangible nor mutually acceptable; therefore, the approaches of metaphysics fail when trying to define any form of intellectually refined concept. The initial conclusion of this statement is obvious: metaphysics does not consist of science (Kant 1999 [1787], 47-8).

In order to convert metaphysics to real science, Kant suggests that the focus of metaphysics should become the ' a priori’ concepts. Of course, the ' a priori’ concepts which are supposed to be examined by metaphysics are not the same as the tangible ' a priori’ concepts of mathematics and physics, which consist of real empirical knowledge. Humans are unable to grasp any concept that lies outside the empirical world; therefore, the discipline of metaphysics concerns concepts beyond human reach. Through metaphysics, humans can only define the transcendental ' a priori’ concept of the Absolute, which coincides with God; however, even this process is problematic and can lead to contradictions (Kant 1999 [1787], 47-8).

According to Kant, the concept of the Absolute is the connective link between Theoretical and Practical Reason. Studies in metaphysics already include the notion of the Absolute, which is used to acquire knowledge. Of course, Kant believes that metaphysical approaches define the Absolute as a speculative concept and do not follow proper scientific methodology. To bridge the gap, Kant proposes a methodological tool he defines as the critique of pure Reason. This tool is meant to pull metaphysics out of the speculative dead end, to define what is Absolute, and to use it to connect both forms of Reason (Kant 1999 [1787], 49-50).

The unification between Theoretical and Practical Reason is the result of Pure Reason. Pure Reason applies theoretical knowledge to improve human lives. The most practical use of Pure Reason is the definition of morality. It is achieved through the collaboration between Theoretical and Practical Reasons, both of which function together under the coordination of the Absolute. In relation to the Absolute, both Kant and traditional metaphysics agree that this is God (Kant 1999 [1787], 52).

The balance between knowledge and faith

The debate between the Empiricists and the Rationalists created a separation between knowledge and faith, which Kant sought to bridge. To do this, Kant restrained the potentialities of knowledge and allowed more room for the development of faith, which at that time was under heavy critique.

According to Kant, the study of nature offers the primary material of human experience. Human logic receives empirical material through the senses and categorises it according to a set of inherent concepts, which Kant calls categories. Such concepts are ‘a priori’ and also universal. The initial categorisations by the human mind take place in relation to space and time; after this categorisation, the mind tests its conclusions by the application of experimental methods. At the end of this process, the human mind composes knowledge as a combination of external empirical data and internally inherent ‘a priori’ categories (Vallianos 2001, 34-7).

On their own, Kant’s categories do not consist of pieces of knowledge; instead, they need empirical data in order to be converted to a synthesis of knowledge. Although composite, human knowledge has certain limitations. The human mind can only explain what is sensed, or in other words, the natural phenomena conceived by the sense organs; however, the essence of such phenomena cannot be conceived by the mind. The reality of the natural world is incomprehensible, lying beyond the reach of the human senses. Based on this rationale, Kant rejects the rational dogmatism of his predecessors and introduces the first epistemological boundaries in scientific knowledge (Vallianos 2001, 34-7).

Kant argues that Human empirical knowledge differs from actual knowledge, which is real yet unreachable by humans. The form of imprinted intellect of the human mind cannot be compared with the archetypal intellect of the Creator; therefore, only God has true knowledge of the actual cosmos. Any human attempt to comprehend this divine cosmos and its objects of Pure Reason is pointless. Kant concludes that there is no rational explanation for the existence of transcendental concepts, such as God or the Soul. Scientific knowledge should be aware of its boundaries, which are found within the limitations of human experience; hence, science should be characterised by humility (Vallianos 2001, 40-1).

In his Critique of Pure Reason, Kant notes the necessity to reject the misconceptions of metaphysics and limit the arrogance of Theoretical Reason, particularly in relation to understanding the Absolute. As an Absolute notion, God cannot be defined by human logic; however, faith assists in the practical improvement of human life. In that sense, Kant abolishes part of knowledge to make space for the growth of faith. He clarifies the role of God in the universe by removing the fallacies and delusions of science and the paraphrases of dogmatic philosophical schools (Kant 1999 [1787], 56-9).

Kant’s hyper-sensible beings cannot be accessed and analysed by Theoretical Reason; hence, there cannot be knowledge about them. Humans can only approach these hyper-sensible beings for their own practical satisfaction through moral reflection. Although Kant recognises laws in nature, he believes that human beings are characterised by freedom of will and freedom of choice. He then visualises a form of morality based on free, conscious human choice rather than compulsion. As the command of Pure Reason, such morality aims to define what is best for all humans as their self-justified cause, thereby laying the foundation for a new society based on quality of life (Vallianos 2001, 42-4).

Human efforts towards moral perfection and a quality of life cannot take place without faith in God, who leads human beings in this direction. With his critique, Kant wishes to free morality from the psychological constraints of Empiricism and place it on a logical basis, independent of fluctuating daily experiences. Of course, Kant acknowledges that present-day societies are characterised by selfishness and egotism, which prevent moral perfection. Kant places the existence of his ultimate moral society in the afterlife and sees it as God’s reward for immortal human souls. In Kant’s approach, posthumous life has solid rational validity, although it cannot be scientifically proven. The immortality of the soul and God become the ultimate quests of Practical Reason (Vallianos 2001, 52).

Kant places religious faith within the boundaries of Pure Reason and defines God as the guarantor of universal moral order. His approach promotes the existence of God and allows religious faith to develop freely. This is probably the reason why contemporary theologians accused him of atheism (Vallianos 2001, 53)

In Kant’s view, the human being is not the possession of the Creator; humans are characterised by freedom of will and freedom of choice. As with Jean-Jacques Rousseau (AD 1712-1778), Kant defends human primacy over God and promotes faith towards fellow humans rather than towards the Creator. For Kant, God is the equivalent of Plato’s Idea: He is meant to guide humans towards moral life. The theological and moral elements of God remain united; however, Kant places greater emphasis on God’s role as the driving force. Kant also suggests that, for the same reason, theology has no direct impact on improving human life. God acts as the guarantor of world order and provides deeper meaning to human life; He commands respect for human laws and love for fellow humans. Kant appears to place the fellow-human above God himself; hence, contemporary theology saw this as a sign of arrogance, which led to Kant’s final conviction by the Church (Pelonidis 2001, Φ102).

Summary and conclusions

Immanuel Kant belongs to the philosophers of the transitional period between the Enlightenment and the 19th century. His thoughts were used to bridge the knowledge gap generated by two previous philosophical movements, Empiricism by David Hume and Rationalism by Gottfried Wilhelm Leibniz. By questioning the existence of real knowledge for humans, Kant limited scientific knowledge in favour of faith in God, who was attributed a practical role in human life.

According to Kant, human knowledge has boundaries. Human beings acknowledge facts that can only be confirmed via human experience. They conclude on these facts based on ' a priori’ categorisations, which are inherent in human intellect. In that sense, human knowledge is just the knowledge of empirical phenomena. By contrast, human intellect is unable to grasp transcendental concepts, such as God or the Soul, which cannot be part of human knowledge. This is where science stops, and faith begins.

In Kant’s theory, the items of empirical knowledge are processed by Practical Reason, and the transcendental concepts are approached by Theoretical Reason. Both forms of Reason do not communicate with each other; however, Kant argues that they can be combined through what he describes as Pure Reason, which aims to define the Absolute. Pure Reason converts sporadic and unsystematic metaphysical quests into official scientific conclusions. To promote this role, Kant bequeaths to the next generations a methodological tool, which bridges the gap between Theoretical and Practical Reason: this is the Critique of Pure Reason. This critique is meant to lead the way towards a new metaphysical science that defines the Absolute and makes it practically useful for improving human life.

Kant’s Absolute is God. Kant's science holds that knowledge of God is impossible because God stands outside the boundaries of human experience. Religious faith and its focus on divine concepts are only meant to guide humans towards moral perfection. If human egotism becomes an obstacle to this moral perfection, the All-wise Creator will offer it to humans post-mortem.

Despite the restriction of scientific knowledge in favour of faith, Kant’s theoretical scheme was criticised by the theological circles of his time. The main theological argument against Kant’s approach was that he granted humans freedom of choice and freedom of will; therefore, he placed them above their Creator. Furthermore, Kant promoted morality as the primary concern for all humans rather than religion. These ‘violations’ of divine order brought him accusations of arrogance, conceit and atheism.

As opposed to the above accusations, Kant’s real intention was to match logic with experience in order to establish the Newtonian understanding of the universe. To do this, he introduced the notion of Pure Reason as an archetype for the definition of transcendental concepts. Through this definition, Kant expected to unify empirical and non-empirical reality. At the same time, he acknowledged the vanity of his aim by arguing on the restrained capacity of scientific knowledge, which was trapped within the boundaries of human experience. Kant’s science was supposed to know this limitation and be modest enough to accept it.

It can be argued that the next generation of scientists and philosophers adopted Kant’s approach and rejected the supposed humility of science. Furthermore, future philosophers modified the archetypal instrument of Pure Reason and founded a new metaphysical science, which led to 19th-century German Idealism (Vallianos 2001, 59).

Bibliography

Kant, I., 1999 [1787], Kritik der reinen Vernunft, second edition, translated by A. Giannara, Athens: Papazisis.
Molyvas, Y. (ed.), 2001, Philosophy in Europe, Volume II, The Age of Enlightenment (17th-18th century AD), Patra: Greek Open University.
Pelonidis, Th., 2001, Introduction to Metaphysics: Critique of Pure Reason, available at www.edit.auth.gr, Φ.102.
Vallianos, P. (ed.), 2001, Philosophy in Europe, Volume III, Modern and Latest Philosophical Movements (19th-20th century AD), Patra: Greek Open University.