In ontology, the theory of categories concerns itself with the categories of being: the highest genera or kinds of entities according to Amie Thomasson. To investigate the categories of being, or simply categories, is to determine the most fundamental and the broadest classes of entities. A distinction between such categories, in making the categories or applying them, is called an ontological distinction. Various systems of categories have been proposed, they often include categories for substances, properties, relations, states of affairs or events. A representative question within the theory of categories might articulate itself, for example, in a query like, Are universals prior to particulars?

• Indefinite Modality
• Definite Modality

Ontology is the philosophical discipline studying the nature and types of existence. Singular existence is the existence of individual entities while general existence refers to the existence of concepts or universals.

• concerning the description whether it is a category which is
  • Concerning absolute , definite , measured , approximate , estimated , known
  • Concerning ambiguity , indefinite , ambiguous , predicament , unknown
• Concerning the understanding of what a concept is according to contemporary philosophy ^[1]
  • Concepts as mental representations, where concepts are entities that exist in the mind (mental objects)
  • Concepts as abilities, where concepts are abilities peculiar to cognitive agents (mental states)
  • Concepts as Fregean senses , where concepts are abstract objects, as opposed to mental objects and mental states.
• Concerning the predicament of priori and posteriori
  • experience , discovery , invention , inspiration
  • mathematical understanding , logic , reason , geometry

• Space

• Primary category
  • Substance
    • genus
      • matter
    • species
      • solid
      • liquid
      • gas
  • सम्बन्ध सिद्धान्त (Relation )
  • Quantity
    • number
    • space
  • Quality
    • property
      • dimensions
      • Size
      • shape
      • form
      • mass
      • energy
      • temperature
      • humidity
      • current
      • material
    • Accident
  • Events or phenomena
    • sound
    • light

• Secondary category
  • Time
  • place
  • situation
  • Condition
  • Action
  • Passion

SINGULAR AND GENERAL EXISTENCE

Singular existence is the existence of individual entities while general existence refers to the existence of concepts or universals.

PHYSICAL AND MENTAL EXISTENCE

In contemporary philosophy, there are at least three prevailing ways to understand what a concept is:

ABSTRACT AND CONCRETE

Entities present in space and time have concrete existence in contrast to abstract entities, like numbers and sets. The type–token distinction identifies physical objects that are tokens of a particular type of thing. The type of which it is a part is in itself an abstract object. The abstract–concrete distinction is often introduced and initially understood in terms of paradigmatic examples of objects of each kind:

In metaphysics, a universal is what particular things have in common, namely characteristics or qualities. In other words, universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. For example, suppose there are two chairs in a room, each of which is green. These two chairs share the quality of chairness, as well as greenness or the quality of being green; in other words, they share two universals. There are three major kinds of qualities or characteristics: types or kinds (e.g. mammal), properties (e.g. short, strong), and relations (e.g. father of, next to). These are all different types of universals.

• INDEFINITE UNIVERSAL CATEGORY
• DEFINITE UNIVERSAL CATEGORY

• relative action and motion
• relative velocity
• social relations

• Variables
  • unknown variable
  • known variable
• parameter
  • known
  • unknown
• known
  • indefinite
  • definite
• unknown
  • indefinite , doubtful , suspicion
  • definite parameter