Critique of Pure Reason

by Immanuel Kant

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Last Updated on June 19, 2019, by eNotes Editorial. Word Count: 393

How We Acquire Knowledge

Kant is very interested in how human beings obtain knowledge of the world around them. He distinguishes between a priori knowledge, the intuitive knowledge we have of certain realities such as mathematics or colors, and a posteriori knowledge, which we acquire after having employed our senses to verify truths. He also distinguishes between two sorts of judgements: analytical judgements, which we make on the basis of self-evident truths, and synthetic judgements, in which we must engage in empirical observation and experiment to verify those truths. The four types of statements that Kant’s formulation of knowledge allow for are as follows:

  1. Analytic a priori
  2. Synthetic a priori
  3. Analytic a posteriori
  4. Synthetic a posteriori

Are all possible with the exception of analytic aposteriori, which is a contradiction.

Things As They Are and Things As They Appear

Kant is also concerned with the ancient question within philosophy as to whether things truly are as they appear to human observation. He does not believe that being and appearance are equivalent, proposing that human observations transform “Noumena,” a term he uses to refer to how things truly are in reality, into “Phenomena,” which is how they appear after being filtered by human understanding. For Kant, human beings are only ever capable of using their understanding on things as they phenomenally appear.

Space and Time

Kant’s examination of space and time as concepts has two parts. Initially, he endeavors to work out how we can know these concepts intuitionally as a priori. Secondly, he seeks to show how we might use our knowledge of these concepts to inform our understanding in other questions. He uses the example of geometry to validate his assertion that space is an a priori yet also a synthetic realm of knowledge. Imagine a triangle and the number three. Alone as a priori statements, these are insufficient to show that a triangle has three sides. A further synthetic step is needed, but this step takes place for Kant within the a priori realm nonetheless. Likewise, time exists as a priori, being that it can be observed at the core of mathematics, science, and every other province of a priori reason, though time does not lend itself to being analyzed under the laws of logic, since it can allow for one incident one minute and the complete opposite the next.

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