Kant's Epistemology: Understanding Knowledge and Reality

Kant's Faculties of Knowledge: Sensitivity and Understanding

Immanuel Kant distinguishes two fundamental faculties of knowledge in human beings: sensitivity and understanding.

• Sensitivity: This faculty is how things are given to us. It is an intuitive, direct, and immediate feeling, but it is passive or receptive. Sensitivity receives stimuli, allowing us to be impressed or affected by something external to us.
• Understanding: This faculty is how we think about our sensations. It is active, spontaneously producing representations, but it is discursive, proceeding step by step.

Kant's Concept of Intuitions

Intuitions are the acts or operations of sensitivity. For Kant, intuition is always sensitive, never intellectual. Human beings lack an intellectual intuition of things, which would possess the advantages of both sensitivity (immediate and direct) and understanding (active). Intuitions are divided into two types: empirical and pure.

Empirical Intuitions Explained

Empirical intuitions are sensations and perceptions—sensory experiences caused by external reality. This raw experience would disintegrate into chaos if it were not unified or organized by what Kant called pure intuitions.

Pure Intuitions: Space and Time

The pure intuitions are space and time. Independent of empirical experience, these intuitions are fundamental conditions that make experience possible. They do not derive from experience but precede it (are a priori), applying to experience and imposing order and structure upon it.

Understanding the Phenomenon

The phenomenon is the unified entity formed by empirical intuitions and pure intuitions; it is sensory experience structured within space and time. The phenomenon represents the appearance of reality—something that manifests to our sensitivity, a 'this-here-now' that is unknown until conceived by the intellect.

Kant's Theory of Concepts

Concepts are the operations or acts of understanding. They are divided into two main classes:

• Empirical Concepts: These concepts, according to Kant, hold little importance in the foundational structure of knowledge.
• Pure Concepts (or Categories): These are crucial for organizing experience.

Pure Concepts: The Categories

There are twelve basic pure concepts, also known as categories, with which we organize experience. These are empty forms of understanding that provide knowledge when applied to experience and are filled by it. They are not images or representations of anything specific, but rather schemes for constructing knowledge from empirical data. With these concepts, we can understand phenomena; we think about what we feel and experience.

At the level of understanding, categories play the same role for concepts that space and time play for sensitivity. Independent of pure experience, categories precede experience—they are a priori—serving as conditions that make knowledge possible.

Defining the Object of Knowledge

The object of knowledge, for Kant, is what we know. It is the categorization of empirical data within space and time; it is thinking about phenomena through pure concepts or categories. Kant also refers to the object of knowledge as the phenomenon.

The Thing-in-Itself (Noumenon)

The thing-in-itself (or noumenon) represents reality as it is, independent of our perception. This reality is unknowable and, indeed, unthinkable by us. It is fundamentally distinguished from the object of knowledge.

We are familiar with objects, but not with the things-in-themselves of reality, because when we attempt to apprehend them, we inevitably modify them with the structures of our sensibility (space and time) and our understanding (categories). However, it makes sense to speak of things-in-themselves and to think of them as existing behind phenomena, for the phenomenon must always be the appearance or manifestation of something; it would be absurd if nothing manifested.

The Self: Object vs. Thing-in-Itself

Kant's theory makes no exception for the 'I' or the self; the self does not enjoy any special privilege in relation to other objects of knowledge. Thus, in introspection, I know myself as a phenomenal object, not as a thing-in-itself. I do not know myself as I truly am, but as I appear before myself, as I experience myself in space and time.

Kant's Theory on the Possibility of Science

From his theory of knowledge, Kant explains why mathematics and physics are possible as sciences.

Mathematics as Science

Mathematics is made possible by the a priori forms of sensibility:

• The a priori intuition of space makes possible a priori synthetic judgments of geometry.
• The a priori intuition of time makes possible a priori synthetic judgments of arithmetic.

This is not to be confused with mathematical logic: logic is analytic, meaning it does not extend knowledge, and it deals with understanding and concepts. Mathematics, however, is synthetic, meaning it expands knowledge, and it deals with sensibility and intuition, albeit at a pure or a priori level, not an empirical one.

Physics as Science

Physics is made possible by the pure concepts of understanding (the categories). The categories allow for a priori synthetic judgments regarding physical first principles and their general laws, as these principles are derived from them.