What is the Transcendental Deduction of the Categories?
An Introduction to Immanuel Kant’s Most Important Philosophical Idea
mmanuel Kant (1724–1804) is one of the most famous philosophers of all time. He is a must for every student philosophy with many reading him in their first year of philosophical studies.
While he is known for many things, but perhaps his most important idea was the transcendental deduction of the categories. This position, laid out in his book, The Critique of Pure Reason, still impacts philosophical research to this day.
In this story, I will outline and breakdown this famous, but often confusing, position. I hope that it might help you all in your attempts to understand Kant and improve your philosophical journey.
What is the Transcendental Deduction of the Categories?
The Transcendental Deduction of the Categories is the way in which concepts are able to refer to objects a priori — meaning independently of any particular experience. In other words, it is how we come to have knowledge of the a priori categories that are universal and necessarily valid at work in experience.
The Transcendental Deduction of the Categories is offered as a response primarily to David Hume, who says that it impossible to empirically deduce objective a priori metaphysical concepts. Kant agrees with Hume but argues that a transcendental deduction of categories is possible.
What Does Kant Mean by Transcendental?
Kant defines transcendental as dealing, “not so much with objects but rather with our a priori concepts of objects.” In other words, the transcendental is concerned with what is necessary for something else to take place.
In the case of the categories, it is the conditions necessary for there to be such a thing as human experience; something which even Hume can agree exists. Kant has to then show the following:
What appearance needs in order to count as experience?
Where these things come from?
How these things are a priori, universal, and necessary?
Having moved from sensations to appearances in the Transcendental Aesthetic — which deals with principles of a priori sensibility —, Kant argues that one has still not reached the level of experience.
We do not have experience of things simply in time and space, which is what appearances are. Rather, we have experience of objects to which appearances contribute.
In other words, when one considers experience, one finds that it contains both appearances and concepts. Yet, the concepts that are a part of experience must come from something besides the appearance, as the appearance is only sensations presented in time and space.
For example, I experience an apple. Yet, if I consider the appearance of the apple in front of me, all I find is the qualia of red, sweet, and round. Nowhere do I perceive ‘apple’. Kant argues that just as time and space are the preconditions for appearance, certain concepts must be in place prior to experience; and just like time and space, must be located in the mind, in particular in the understanding.
What Kantian Categories Are About?
Kant calls the concepts that are imposed on appearance by the mind the categories.
Categories are the fundamental principles by which the disorganized atomistic manifold is organized into objects of experience. Kant gives twelve such categories, organized in four sets of three.
Quantity: unity, plurality, and allness.
Quality: reality, negation, and limitation.
Relation: inherence, causality, and community.
Modality: possible, existence, and necessity.
For Kant, all appearances are organized in at least one of these twelve ways; thus allowing it to rise to the level of experience.
If it is the case that one is given the ‘stuff’ — the disorganized atomistic manifold — from appearance and concepts are provided by the understanding, then how is it possible that the two are connected?
Kant acknowledges that in experience, “a category already presupposes a combination;” That is, a combination of concept and appearance in an object. Kant claims that this combination is a synthetic unity.
This is to say that something other than appearance and concepts is required prior to their combination. Implied in a synthetic unity is the need for something external to synthesis the two. Kant calls this unity before the unity of appearance and concept the transcendental unity of apperception.
What Is the Function of the Transcendental Unity of Apperception?
The transcendental unity of apperception is the unity within appearance to present bundles of perceptions as going together. Peter Frederick Strawson says,
it must be one and the same understanding which is busy at its conceptualizing work on all the intuitions belonging to a single consciousness.
That is, the appearance of red, sweet, and round must be connected before they can be subsumed under a concept.
For what it is for something to fall under the concept of ‘apple’, and be experienced as such an object is not just one of the above perceptions but the set of them.
Yet, there is still a need to account for the act of connecting the now unified manifold with concepts. Kant claims that it is the imagination which performs this act.
Kant thinks of the imagination, in a way, as the force required to join appearance and concepts which are essentially distinct. Strawson puts it this way:
[A]ll combination, all connexion is produced by imagination which assembles and reproduces as necessary the discrete data of sense, acting always under the control of understanding, the source of concepts.
For example, the imagination takes the bundle of red, sweet, and round and with the pure concept of ‘apple’ provided by the understanding, unifies the two to form the image of an apple, which allows for the experience of an apple.
It is now that Kant says that one has finally reached the level of experience. With the unity of apperception, concepts provided by the understanding, and the connective force of the imagination unifying the two, we are able to experience objects in the way that is familiar to us.
A Debate Between Kant and Hume
What is interesting to note is just how much Kant thinks Hume missed when he considered experience. Experience is far from given to us ready-made; rather we supply two-thirds of the necessary components of experience.
We provide not only the concepts, that appearances are subsumed under, but the unification of the appearances which allow them to be understood as falling under a certain category. Further, we also provide the actual combination of the components of experience via the imagination.
How, then, is all of this a priori, necessary, and universal if we supply so much?
Simply put, the categories and the unity of apperception are a priori, universal, and necessary as a result of being deducted via a transcendental method.
When one brackets out everything that is a posteriori, particular, and contingent (i.e. everything found in experience), what is left must be a priori, universal, and necessary.
Considering each in particular, the fact that the categories and the unity of apperception cannot be found in experience, something Hume proved extensively, means that they are not a part of experience and are thus a priori. While Kant does claim that we require experience to become aware of them, they are not themselves empirical.
The categories and unity of apperception are necessary due to the fact that Kant shows that they are presupposed by our notion of experience. There would be no such thing as experience without them being in place. The categories and unity of apperception are universal in that every person experiences in the way that Kant describes.
Since the categories and unity of apperception are necessary, one would not have something worth calling experience as we know it without them. Further, the categories and unity of apperception are not subject to the control of the subject. I cannot choose not to experience objects in a different way than the way that we all, as humans, do. This means that they must be objective rather than subjective.
Finally, why must there even be a Transcendental Deduction of the Categories?
Why Is the Deduction Considered Necessary?
If the categories are a priori, necessary, and universal, then why must one work through the empirical to determine them?
The reason the deduction is necessary, according to Kant, is that they are not innate, that is, we do not have innate knowledge of them. Contrary to others such as Plato and Descartes, it is only when we have experience, that is at least one experience, that it becomes possible to become aware of the categories. This is to say that we are only able to know the categories by “catching them in the act.”
For example, if one never experiences anything, the concept of quantity will never arise as there will be nothing that has quantity. Kant says:
Without sensibility no object would be given to us; and without understanding, no object would be thought. Thoughts without content are empty; intuitions without concepts are blind.
Once we have experience one is able to separate out what belongs to experience and see what remains and call it transcendental.
Conclusion
While the importance of Kant and the transcendental argument in professional philosophy are indisputable, what about their importance beyond the academy?
What we can take away from Kant’s transcendental deduction for the categories is not so much the details as the approach itself. The transcendental deduction for the categories came at a time in philosophy when skepticism and subjectivity seemed unbeatable. There was simply no way to say with certainty that there was anything universal about the world one experienced.
The result of this defeat of skepticism was a renewed interest in scientific study as human experience was once again connected to objective reality. In other words, we could again trust experiments and their results, especially when it came to things related to time and space.
Kant's argument shows that from even the most simplest of things (i.e. a simple experience), we are able to deduce universal truths. Thus, it shows that even when we feel that there is no possible common ground, there is still hope for finding something, even if it is just that we are both human living in time and space.
References
Kant, Immanuel, Critique of pure reason (Cambridge: Cambridge University Press, 2009).
Morris, William Edward and Charlotte R. Brown, “David Hume”, The Stanford Encyclopedia of Philosophy (Winter 2023 Edition), Edward N. Zalta & Uri Nodelman (eds.).
Pereboom, Derk, “Kant’s Transcendental Arguments”, The Stanford Encyclopedia of Philosophy (Fall 2024 Edition), Edward N. Zalta & Uri Nodelman (eds.).
Strawson, Peter, The Bounds of Sense (London: Harper and Row, 1973).
Snowdon, Paul and Anil Gomes, “Peter Frederick Strawson”, The Stanford Encyclopedia of Philosophy (Summer 2023 Edition), Edward N. Zalta & Uri Nodelman (eds.).