Immanuel Kant (1724-1804)

References

The Philosophical Dictionary.

Kant: Synthetic A Priori Judgments

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Wikipedia.

Immanuel Kant

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Key Concepts

Kant asserted that human reasoning is devoted to asking the simple question, "How will I live my life in the future?" He noted one could never know for certain if there is a God and an afterlife. But, then again, one could not be certain that these entities did not exist! So, as a practical matter, one might as well behave as if they did exist. He noted that if one can neither prove nor disprove a thing, then one might reasonably ask if it is in one's interest to accept the thing as real as a matter of practicality. Hence, the question is not whether the thing exists, but whether it is practical to assume that it does. Metaphysics should focus upon what is experienced and how it is experienced rather than wondering what really exists.

Kant therefore distinguished between "

phenomena

, things as they appear to our senses, and

noumena

, things that are purely objects of thought independently of sense perception, which, by definition, we can never experience" (

The Philosophy Dictionary

). Thus, Kant offers a "critique of pure reason," or attempts to understand and know what can never be understood or known.

In his influential book,

The Critique of Pure Reason

, Kant attempts to reconcile rationalism (i.e., reliance upon reason as a method of knowing) and empiricism (i.e., reliance upon observations as a method of knowing). David Hume had argued effectively that cause and effect cannot be inferred from observations alone; one must use reason as well. At the same time, Kant thought that sound reasoning demanded grounding in empirical observations. Kant's

transcendental idealism

reconciles rationalism and empiricism by arguing that a reality exists that we might, by reason, know about. But we can never know the true nature of this reality because our knowledge of it is always filtered through our limited perceptions of it.

Notes

Kant bridged rationalism and empiricism by noting that the mind shapes the world as we observe it. In the same manner as Copernicus taught us to view the solar system from the point of view of the observer, Kant taught us to view reality through the lens of the observer. He did not reject rationalism, which was needed to order our observations. He did, however reject pure reason. He retained the central premise of the Enlightenment, which was a reliance upon empirical observation, but noted that all observations were colored by reason and necessarily organized by reason. Kant also taught scientists to act with a sense of pragmatism. We can never know "the truth." We can, however, act upon the world based upon our best guesses about causes and effects.