Kant's Three Critiques Explained 1/3

Critique of Pure Reason: What Can We Know?

There are certain philosophers that are important but opaque. And more opaque because they won the debate. Their assumptions are often our assumptions and therefore unquestioned. One of those philosophers is Immanuel Kant (1724–1804).

Kant’s system itself was influencial, but it did not win out. What did win out what where he believed the new starting point of the philosophical conversation.

Immanuel Kant’s philosophy is built on three major critiques, each addressing a fundamental question about knowledge: What can we know? What should we do? And what is beauty and purpose? I plan to summarize each and then give a critique of his system of critique.

Critique of Pure Reason (1781): What Can We Know?

Kant explores the limits and capacities of human reason, particularly in relation to knowledge. He distinguishes between two types of knowledge: a priori, which is independent of experience, and a posteriori, which comes from experience. He argues for transcendental idealism, the idea that we can only know things as they appear to us (phenomena) but never as they truly are in themselves (noumena). Our experience of the world is shaped by built-in categories in our mind, such as causality and substance, which structure our experiences of the otherwise unrelated phenomena of color, shape, motion, etc. we actually take in with our senses.

Phenomena are the things as they appear to us—the reality that is filtered through our senses and then structured by our minds. Kant argues that our perception of the world is shaped by a priori categories of understanding (such as space, time, and causality). Our mind categorizes and organize sensory input into coherent experiences. We see a ball rolling, we naturally perceive movement over time and mind attributes causality (the push causes it to roll). This structured world of experience is what Kant calls the phenomenal world. It is sense perception plus the organization our mind adds.

Noumena, on the other hand, refer to things as they are in themselves, independent of human perception. This is reality beyond our senses and mental structures—what truly exists outside our experience. However, Kant argues that we can never know noumena directly because all our knowledge is mediated through the way our minds shape experience. Noumena is, by definition, that which is beyond sense perception. By Kant’s definition of knowledge (derived from Plato), it cannot be known. We can think about noumena as a concept (for example, we might wonder about what an object is beyond how we perceive it), but we cannot perceive or understand them in any concrete way. And only the concrete fits the the prerequisite category of knowledge, (though there are other things necessary as well).

Kant does not deny the possibility of metaphysical realities. He denies the possibility of our knowledge of those realities by developing a two tiered understanding of knowledge. We do not perceive the world as it is, but rather as it appears to us through the structure of our minds. This can be called knowledge, because minds share the same structure, but it isn’t knowledge of the things outside of us. We can’t know things in themselves.

The Impressionist movement was the artistic expression of this starting point. Monet and others sought to capture immediate visual experience rather than objective reality, because we aren’t the kind of creature for whom objective reality is available to know.

This new starting point became the norm. Even though Kant’s answer is not embraced, his assumptions were.