2.3 Immanuel Kant and Perception

Let us fast-forward to the 18th century. The field of MetaphysicsA branch of Philosophy that explores the nature of reality. underwent a radical transformation due to German philosopher Immanuel Kant (1724–1804). Kant shifted the focus from the external world to the limits of human perception, asking not just “What is real?” but “How do we know what is real?”.

The Two Worlds

Kant argued that there are two aspects of “reality”:

• The phenomenal world: This is the world as we individually experience and perceive it, which is filtered and shaped by our preconceptions. He stated that these perceptions are pre-existing frameworks in our minds that shape how we perceive and interpret the world, which includes concepts, categories, and moral principles. 
• The noumenal world: This is the “real world”, that is, reality as it exists independently of our perception of it. Kant argued that we can never truly experience or know this world because the raw sensory data of our experiences are interpreted and shaped by our mind.

This proposed a new perspective on the mind, one where we are not simply taking in sensory information and experiencing it exactly as it is, but one where our mind is actively filtering and shaping our experience of the world.

Likewise, Kant’s approach offered a radical new perspective on reality. Previous influential thinkers such as Isaac Newton had argued that space and time are fundamental features of the external world. In other words, they actually exist in reality. 

By contrast, Kant argued that space and time are not fundamental parts of the external world. Instead, they are mental constructs that help us to organise sensory information in our minds. He argued that we perceive objects in space and time because our mind imposes these structures onto the raw sensory data that we take in.

Throughout this course, you will see how the various thinkers influenced, expanded upon, and argued against each other’s ideas like this for centuries.