Classification of the Idea

This Article groups ideas according to five aspects or bases of classification:

• a) Origin
• b) Perfection in representing
• c) Comprehension
• d) Extension
• e) Relations

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a) Origin: Intuitive and Derivative

Intuitive ideas are those which originate in the direct grasp of that which they represent. Such are the ideas formed immediately upon sensation — ideas of sensible things, and ideas one forms of one’s own feelings and thoughts.

Derivative ideas are derived from intuitive ideas. Such are the ideas of supersensible things like soul, spirit, God, unity, truth. Such also are the ideas that originate in arbitrary synthesis of intuitive ideas — ideas like a sea of fire, a golden mountain, a talking tree.

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b) Perfection: Clear, Distinct, Complete

1. Clear / Obscure. An idea which represents its object as discernible from all other objects is clear; otherwise it is obscure. If I know the circle merely as a plane figure, my idea is obscure, because the circle as a plane figure is not discernible from the triangle, the quadrilateral, etc. When I come to know the circle as discernible from all other plane figures, my idea becomes clear.

2. Distinct / Vague. A clear idea that presents its object in such wise that the more important essential notes are distinguishable one from another is distinct; otherwise it is vague or confused. If I am able to distinguish what the circle is in itself as well as to know it from other plane figures, my idea is clear and distinct. If I merely know it as discernible from other plane figures, without being able to give any sort of definition of it in itself, my idea is clear but vague.

3. Complete / Incomplete. When an idea is so perfectly distinct that all its essential notes can be distinguished and enumerated, the idea is complete; otherwise, although clear and distinct, it is incomplete. If I know that man is a rational animal, my idea is distinct — but it is not complete unless I can enumerate the essential notes comprised in the idea animal (viz., bodily, living, sentient substance).

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c) Comprehension: Simple/Compound; Concrete/Abstract

1. Simple and Compound. Ideas that have but one note in their Comprehension are simple. Ideas that have more than one such note are compound. The idea of being (and its synonyms and equivalents) is simple. The idea of man — although representing a single essence — is compound, for it has six essential notes in its Comprehension.

2. Concrete and Abstract. An idea that represents something as a substrate or subject together with its determinant is concrete. An idea that represents a determinant as separated from a subject is abstract. The idea man is concrete, for it represents some thing with the determinant humanity. The idea humanity is abstract, for it represents the determinant apart from its subject.

• Examples of concrete ideas: body, spirit, object, white horse, pious man.
• Examples of abstract ideas: bodiliness, objectivity, whiteness, piety.

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d) Extension: Singular, Universal, Particular, Transcendental

1. Singular. An idea that has only one object in its Extension is singular. Such are the ideas of this circle, my father, Herbert Hoover, Pittsburgh, Ohio.

2. Universal. An idea which represents an essence that many objects may have is universal. Such are the ideas of circle, father, president, city, state.

3. Particular. A universal idea taken partially and indeterminately is particular. Such are the ideas of some circles, many fathers, certain presidents, a few cities, numerous states.

4. Transcendental. An idea that is so general or universal that it transcends the bounds of class and applies to all classes and individuals (though not in precisely the same manner and sense to each) is transcendental. The idea of being is transcendental.

Note that the universal idea differs from the collective idea. A collective idea signifies a number of individuals taken as a unit, but does not represent an essence common to all the individuals, only to the group unit. Thus the ideas of army, jury, family, committee are collective ideas. The collective idea may itself be singular (this army), universal (all juries), or particular (some families).

The universal idea is a subject of supreme importance in Dialectics, and receives its own full treatment in the next Article.

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e) Relations: Identical/Different; Associable/Opposed

1. Identical and Different. Ideas that have the same Comprehension or Extension are identical. Those with the same Comprehension are formally identical (e.g., man and rational animal). Those with the same Extension are materially identical (e.g., John Brown and this sailor, or Herbert Hoover and our president). Non-identical ideas are different.

2. Associable and Opposed. Different ideas that are not mutually exclusive and may be harmoniously joined in the same idea are associable or congruous (e.g., living and sentient). Ideas that are not associable are repugnant or opposed.

Opposed ideas take four forms:

i. Contrary. Two opposed ideas are contrary when they exclude each other but leave a ground between them — they do not exhaust the possibilities. Black and white are contrary: they exclude each other, but there are many things neither black nor white.

ii. Contradictory. Two opposed ideas are contradictory when they exclude each other and leave no common ground — they exhaust all possibilities. White and not-white are contradictory: there is nothing conceivable which is neither white nor not-white.

iii. Relative. Two opposed ideas stand in the opposition of relation when one implies the other as a different object. Parent and child are relative: the idea parent involves the idea child but indicates that what is parent is not at the same time child. The idea involved in another is an implicit idea; the other is the explicit idea. Examples: husband/wife; superior/inferior; ruler/subject.

iv. Privative. Between two opposed ideas there exists privation when one is the idea of a perfection that should be present in a given subject, and the other is the negation of that perfection. Sight and blindness (with reference to man) stand in the opposition of privation. The privative idea is merely negative (not privative) when it denotes the absence of a perfection in a subject that could not have that perfection in any case — e.g., blindness applied to a stone.

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Summary of the Article

Ideas are classified as follows:

a) By Origin: intuitive / derivative

b) By Perfection:

• obscure → clear → distinct → complete

c) By Comprehension:

• simple / compound
• concrete / abstract

d) By Extension:

• singular · universal · particular · transcendental

e) By Relations:

• identical: formally (same Comprehension) / materially (same Extension)
• different: associable / opposed
  • opposed by: contrariety · contradiction · relation · privation