Critique of Traditional Metaphysics: Kant’s Transcendental Idealism
Criticisms of Traditional Metaphysics
In the preface to the Critique of Pure Reason, Kant expresses his primary concern with the possibility of metaphysics. Specifically, he questions whether it is possible to secure knowledge about God, freedom, and the immortality of the soul.
There are two reasons for doubting the possibility of metaphysics:
- Science progresses, while metaphysics continues debating the same issues discussed centuries ago.
- Scientists agree on their theories and conclusions, while metaphysicians exhibit significant disagreement.
Therefore, it’s necessary to consider whether metaphysics is possible as a science. If it were, Kant believes, metaphysics would surpass its stagnant state and achieve agreement and progress. If not, it’s best to abandon the illusion of building metaphysical systems with pretensions of scientific knowledge.
The Transcendental Dialectic aims to answer the question of metaphysics’s possibility. However, if we accept the analysis of knowledge conducted in the Transcendental Aesthetic and Transcendental Analytic, it seems there’s nothing more to say about metaphysics. This analysis leads to some general conclusions about the subject. Fundamentally, metaphysics is possible as a science insofar as we can call transcendental criticism itself metaphysics. However, traditional metaphysics is not possible because it assumes the application of categories outside their legitimate scope.
The cognitive function of categories lies in their application to objects given in sensuous intuition. Things-in-themselves are not phenomena and cannot be intellectually intuited. Therefore, they cannot provide objects for a meta-phenomenal application of categories. This excludes classic metaphysics as objective knowledge.
However, Kant’s stance on metaphysics is more complex. He believed the metaphysical impulse is an ineradicable human drive. Metaphysics is possible and valuable as a natural disposition. Furthermore, Kant wants to illustrate and confirm this truth through a detailed critique of rational psychology, cosmology, and natural theology. The Transcendental Dialectic serves both purposes.
Natural Disposition to Metaphysics
To explain the natural disposition of human reason to metaphysics and its value, Kant states:
The understanding directly addresses phenomena and unifies them in judgment. Reason, as part of a syllogism, seeks the maximum unity, the unconditioned, which is not given by experience (transcendental ideas).
The unconditioned is a pure concept of reason. Kant believes there must be as many pure concepts of reason as forms of reasoning or syllogisms. He identifies three transcendental ideas following three pure concepts of reason: the idea of the soul, the idea of the world, and the idea of God.
Transcendental ideas are not valuable for establishing knowledge; they cannot have a transcendent use. They cannot be treated as objects of knowledge because they cannot be given to intuition (either sensible or intellectual). However, they have regulative value, providing a rule to expand knowledge and possessing an inherent use. The idea of the self encourages greater integration of psychic phenomena, the idea of the world encourages greater integration of natural phenomena, and the idea of God leads us to think about natural phenomena as a teleological and systematic unit.
Critique of Metaphysics
Regarding the detailed critique of metaphysics, Kant proceeds as follows:
Kant’s metaphysics is ultimately subject to a review of Wolff’s special metaphysics, divided into three disciplines:
- Rational psychology, whose object is the soul
- Rational cosmology, which aims at the world as a whole
- Natural theology, which seeks to demonstrate and know God
Rational Psychology
Rational psychology, in treating the soul as an object of knowledge, gives rise to four paralogisms. The first is to apply the category of substance to the “I think.”
Rational Cosmology
The critique of rational cosmology leads to antinomies—contrary claims, thesis and antithesis, about the world, which can be demonstrated both ways. There are four antinomies of pure reason:
- Thesis: The world has a beginning in time and is limited in space. Antithesis: The world has no beginning in time and no limits in space.
- Thesis: Every substance or compound thing is made up of parts that are ultimately indivisible. Antithesis: No compound thing is made up of indivisible ultimate parts; there is nothing simple, since the possibility of internal division is infinite.
- Thesis: Natural causation is not the only causation in the world; there is also a causality of freedom. Antithesis: There is no freedom; everything that happens in the world happens according to natural causes.
- Thesis: There is a necessary being that is either part of the world or its cause. Antithesis: An absolutely necessary being cannot be either a part of the world or its cause.
The first two antinomies have no solution; they are the consequence of taking space and time as things-in-themselves. The latter two may have another solution: the antitheses relate to the world of phenomena and, as such, are true. The theses could possibly be shown to refer to the noumenal world if a path to it other than that of knowledge were discovered. Kant will find this route in morality.
Natural Theology
Kant’s critique addresses three basic proofs that, in his view, do not conclude:
- Ontological proof: The concept of a perfect being includes all possible perfections. The consideration of the idea of a perfect being implies its actual existence. Kant criticizes this by stating that existence is not a perfection but a category of understanding that adds nothing to our knowledge.
- Cosmological proof: If there is a contingent being, there must also be an absolutely necessary being as its cause. Its misstep is to use the category of causality without justification. It would only be justified by relying on the ontological argument, which we have seen does not conclude.
- Physico-teleological proof: Based on the order and regularity in the world, it concludes that there is a highly intelligent creator, God, responsible for this wonderful order. One could assert the existence of an intelligent architect as the cause of order, but not a creator; to affirm the latter would require relying on the cosmological proof, which in turn relies on the ontological.
Conclusion
In conclusion, Kant’s critique establishes that, although only phenomena are knowable, noumena are at least conceivable. This opens the way for practical or moral reason to push the limits of experience and reach the unconditioned. Freedom, immortality, and the existence of God are postulates of practical reason.
- Freedom must be assumed as a condition for morality (only a free being can have moral duties).
- The immortality of the soul must be postulated because reason demands a perfect match between the will and the moral law, which is not possible in a finite time.
- The existence of God must be postulated because there must be a being that ensures a perfect match between what is and what ought to be, a being that is perfectly just and intelligent to match happiness appropriately with virtue.