The categories of the understanding are used in Immanuel Kant

Immanuel Kant

Immanuel Kant was a German philosopher from Königsberg , researching, lecturing and writing on philosophy and anthropology at the end of the 18th Century Enlightenment....

's philosophy

Philosophy

Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

.

Categories are a priori

A priori and a posteriori (philosophy)

The terms a priori and a posteriori are used in philosophy to distinguish two types of knowledge, justifications or arguments...

 features of our mind that permit our sensible apprehension and ordering of representations of objects. The categories include substance, quantity, quality, relation and modality:

Quantity - Unity, Plurality, Totality.

Quality - Reality

Reality

In philosophy, reality is the state of things as they actually exist, rather than as they may appear or might be imagined. In a wider definition, reality includes everything that is and has been, whether or not it is observable or comprehensible...

, Negation, Limitation.

Relation - Inherence

Inherence

Inherence refers to Empedocles' idea that the qualities of matter come from the relative proportions of each of the four elements entering into a thing. The idea was further developed by Plato and Aristotle....

 and Subsistence, Causality

Causality

Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....

 and Dependence, Community.

Modality - Possibility

Possibility

Possibility is the condition or fact of being possible. The Latin origins of the word hint at ability. Possibility also refers to something that "could happen", that is not precluded by the facts, but usually not probable...

 or Impossibility, Existence

Existence

In common usage, existence is the world we are aware of through our senses, and that persists independently without them. In academic philosophy the word has a more specialized meaning, being contrasted with essence, which specifies different forms of existence as well as different identity...

 or Non-Existence, Necessity or Contingence.

See Category (Kant)

Category (Kant)

In Kant's philosophy, a category is a pure concept of the understanding. A Kantian category is a characteristic of the appearance of any object in general, before it has been experienced...

for further information.