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Immanuel Kant’s Categories of Understanding

Visual by Karen Coelho

Immanuel Kant (1724 –1804) was a German philosopher and a key figure of the Enlightenment. Kant is regarded as one of the most significant figures in modern Western philosophy due to his thorough and systematic works in the field of epistemology, metaphysics, ethics, and aesthetics. David Hume’s work arose Kant from his “dogmatic slumbers” as famously claimed in his Prolegomena to future metaphysicians. Hume’s thoroughgoing empiricism rendered causality nothing but a subjective, psychological mechanism devoid of logical sanctity, and ultimately led him to skepticism regarding knowledge. For Kant, the most important revelation of Hume’s work was that he showed how our most fundamental metaphysical principles lack a rationalistic justification for our belief in them. He agreed with Hume that we have no indubitable knowledge of causality, but thought that his skepticism was misguided. Instead, he hypothesized the structuring of the human mind through the categories of understanding.

A category is a pure concept of understanding that structures the human mind. It is a feature of any object's appearance in general, before it has been experienced- it is required even for the potential of gaining experience. They are notions of an object in general, by means of which its intuition (its spatio-temporal data) is viewed as determined with relation to one of the logical functions for judgments. The categories are pure primal notions, i.e., a priori knowledge (know-how) for the production of concepts, and they cannot be expressed in any sensual intuition as such.

Kant's monumental breakthrough in philosophy, the transcendental method, allowed him to fuse the salient objectives of rationalism and empiricism, the two integral yet distinct views of philosophy. Rationalism attributed intellectual intuition (i.e., innate ideas) to humans dispensing the notions of universality and necessary factual knowledge whereas empiricism accorded the sensible intuition, hindering the rationalist approach. Kant helped bridge this gap by agreeing with empiricists that all human factual knowledge begins with sensible intuition (the only kind we have), and by agreeing with rationalists that we bring something a priori to the knowing process. Factual knowledge, according to Kant, involves both sensory experiences, which provide its content, and a priori mental structures, which provide its form. It is insufficient to have one without the other. He famously writes, “Thoughts without content are empty, intuitions without concepts are blind”. There is nothing for us to know without empirical, sense content; nevertheless, without such a priori frameworks, we have no method of giving intelligible form to whatever content we may have.

Objective empirical judgments (i.e., empirical judgments that purport to refer to objects rather than merely subjective seemings or connections of sense impressions, and which purport to be universally valid for all judging subjects: the temperature of your coffee rather than the way it burns your tongue) are endowed with objectivity and generality in virtue of the a priori concepts embodied in the relevant forms of judgement, according to transcendental idealism. We can hope to uncover all of the most general ideas or categories that are used in making such judgements, and hence that are used in any cognition of things, if we can identify all of the potential kinds of objective empirical judgement.

In presenting four ways to describe any judgement, Kant begins with Aristotelian logic, outlining four ways to classify it: according to its amount, quality, relation, or modality. The key to identifying the twelve associated ideas of the understanding is to use these Aristotelian ways of sorting judgments. Kant ultimately distinguishes twelve pure concepts of the understanding, divided into four classes of three: 1. Quantity (Unity, Plurality, Totality), 2. Quality (Reality, Negation, Limitation), 3. Relation (Inherence and Subsistence (substance and accident), Causality and Dependence (cause and effect), Community (reciprocity)), and 4. Modality (Possibility, Existence, Necessity).

In this way, we can acquire knowledge of categories governing any possible object of cognition by delineating the concepts that are a priori necessary for object cognition. We can thus acquire a sort of descriptive set of ontological categories (though these must be understood explicitly as categories of objects of possible cognition, not of the thing in itself) by delineating the concepts that are a priori necessary for object cognition. Kant's categories have their origins in human understanding principles rather than inherent divisions in mind-independent reality, and that they can be discovered by paying attention to possible forms of human judgement rather than studying the world itself or our contingent ways of speaking.

By seeing the human as something that is tethered to the objective world only through his experience of it, Kant was able to realize the limits of our knowledge. He drew a hard line between the appearances (object as it appears to us) which is all one can know and the object as it exists independently and objectively which will forever remain elusive to us. Modern science seems to corroborate Kant’s hypothesis. The world seems to be very different from our intuitive ideas- down to the very fundamentals of space and time. Many neuroscientists now hold that perception does not just depend on the signals coming from the external world, it also depends on perceptual predictions coming from within the brain. We don’t just passively perceive the world; we actively generate it. Apart from the obvious limitations of our senses, our concepts seem inadequate to even ask questions about the true nature of reality, let alone capture it as it is.



Immanuel Kant, ‘Prolegomena to Any Future Metaphysics’

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