Mastering Definition Types: Rules for Logical and Effective Definitions

Ideal and Effective Definition Types

Definition by Comprehension (Ideal Scheme)

Definition by comprehension follows the ideal scheme: definiendum = superordinate concept + essential characteristics. If defined outside a system, all concepts must be known to the user. Example (Crab Trap): A type of fishing gear with a square base, specifically designed to catch crab species (e.g., crabs and crayfish).

Definition by Extension: Listing Concepts or Objects

Definition by extension can be achieved in three ways:

• A) Listing all subordinate concepts (Classification Level): Example: This thesis defines 'representation of a concept' as: term, definition, explanation, and illustration.
• B) Listing all individual objects: Example: The planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
• C) Stating the rule that leads to the enumeration: Example: Prime numbers are integers greater than 1 that are only divisible by 1 and themselves.

Genetic and Operational Definitions

A genetic or operational definition relates the various operations necessary for determining the definiendum. Example (Report): A description, oral or written, of the characteristics and circumstances of an event or issue.

Contextual Definition (Definition by Example)

A contextual definition is formulated by providing an example. Example: 'Portrait of my brother with a camera.' (This sentence defines the camera by its context of use.)

Nominal Definition (Substitution)

A nominal definition is defined by substituting a difficult-to-understand name with a more familiar synonym. Example: Concept is defined as an opinion.

Types of Defective Definitions

Narrow Definition

A narrow definition chooses a feature that overly limits the scope, excluding one or more objects that should be included. Example (Medicine Bottles): 'Bottles that are made of glass and used to store medications, preferably liquid.' (This excludes plastic bottles or solid medications.)

Overly Broad Definition

An overly broad definition fails to include specific characteristics necessary to exclude objects that do not belong to the defined concept. Example (Hinge): 'Binding element.' (This definition is too broad, as many things are binding elements, not just hinges.)

Negative Definition

A definition should generally avoid denial unless the concept itself is inherently negative. Example (Celibate): 'Unmarried.' (This is acceptable because the concept celibate is defined by the absence of marriage.)

Circular Definition

A circular definition occurs in two main cases:

1. The definiendum appears in the definiens (unless part of a defined system). Example: ISO Standards: Standards issued by the ISO.
2. Using an equally unknown synonym. Example (for children): Car: An automobile... (If 'automobile' is unknown to the audience).

Redundant Definition

A redundant definition includes non-essential or superfluous features. Example (Table): 'Furniture that is made of material such as wood, iron, or acrylic.' (Specifying the material type is often redundant if the essential function is already defined.)