# Dominant group/Genus differentia definition

"A genus-differentia definition is a type of intentional definition ... composed by two parts:
* a genus (or family): An existing definition that serves as a portion of the new definition; ... [and]
* the differentia: The portion of the new definition that is not provided by the genera." Bold added.
There are rules for definition by genus and differentia.
“Where a synonymous definition is unavailable or inappropriate, we can use a definition by genus and difference.” “The possibility of defining terms by genus and difference depends upon the fact that some properties are complex, in the sense of being analyzable into two or more other properties.”
“One defines a term by genus and difference by naming a genus of which the species designated by the definiendum is a subclass, and then naming the difference which distinguishes it from other species of that genus.”
Dominant group may lend itself to this form of definition. Alternately, its relative synonyms may fit into a pattern of genera differentia.

## Theory of definitions

Def. "[a] distinguishing feature which marks something off from other members of the same family" is called a differentia.
Def. "[t]he attribute that distinguishes a species from others of the same genus" is called a differentia.
Def. "a rank in the classification of organisms, below family and above species; a taxon at that rank" is called a genus.
Def. "[a] group with common attributes" is called a genus.
Def. "[w]ithin a definition, a broader category of the defined concept" is called a genus.

## Rules

"Certain rules have traditionally been given for this particular type of definition." which are
* "A definition must set out the essential attributes of the thing defined."
* "Definitions should avoid circularity. A definition of a term must not be comprised of terms which are synonymous with it. This would be a circular definition, a circulus in definiendo."
* "The definition must not be too wide or too narrow. It must be applicable to everything to which the defined term applies (i.e. not [leave] anything out), and to nothing else (i.e. ... include [more objects or entities] to which the defined term [applies]."
* "The definition must not be obscure. The purpose of a definition is to explain the meaning of a term which may be obscure or difficult, by the use of terms that are commonly understood and whose meaning is clear."
* "A definition should not be negative where it can be positive."

## Genera differentia

The genera differentia for possible definitions of dominant group fall into the following set of orderable pairs:
Genera differentia for "dominant group" :
| Synonym for "dominant" | Category Number | Category Title | Synonym for "group" | Category Number | Catgeory Title |
| “superior” | 36 | SUPERIORITY | "arrangement" | 60 | ARRANGEMENT |
| “influential” | 171 | INFLUENCE | "class" | 61 | CLASSIFICATION |
| “musical note” | 462 | HARMONICS | "assembly" | 74 | ASSEMBLAGE |
| “most important” | 670 | IMPORTANCE | "size" | 194 | SIZE |
| “governing” | 739 | GOVERNMENT | "painting", "grouping" | 572 | ART |
| "master" | 747 | MASTER | "association", "set" | 786 | ASSOCIATION |
| ----- | --- | ------- | "sect" | 1018 | RELIGIONS, CULTS, SECTS |
'Orderable' means that any synonym from within the first category can be ordered with any synonym from the second category to form an alternate term for dominant group; for example, "superior class", "influential sect", "master assembly", "most important group", and "dominant painting". "Dominant" falls into category 171. "Group" is in category 61. Further, any word which has its most or much more common usage within these categories may also form an alternate term, such as "ruling group", where "ruling" has its most common usage in category 739, or "dominant party", where "party" is in category 74. "Taxon" or "taxa" are like "species" in category 61. "Society" is in category 786 so there is a "dominant society".

## Mosby's dominant group

In Mosby's Medical Dictionary definition that a dominant group is "a social group that controls the value system and rewards in a particular society." is a synonym for "ruling": "controls", which is a verb form of "controlling".
Combining two genera ('class' and 'sect') with two differentia ('superior' and 'ruling') provides a series of definitions for dominant group.
Def. a class that rules superiority and the sect is called a dominant group.
This is close to "a social group that controls the value system and rewards in a particular society."
By reducing Mosby's definition to "a class (group) that rules (controls) superiority (value system) and the sect (rewards, such as membership in the sect)", the core meaning of dominant group is isolated. Adding "social" and "a particular society" may not be needed to convey dominant-group meaning but places the definition in several fields such as anthropology, psychology, or sociology.
Alternately, "a class (group) that rules (controls) superiority (value system and rewards) and the sect (such as membership in the sect)" also matches the core meaning of dominant group.

## Mosby's five conditions

With Mosby's definition, the essential attributes are set out. (Rule 1)
The genera (class and sect) are relative synonyms of 'group'. But, they can be put into a hierarchy (class > sect). The differentia (rules and superiority) or (superior and rules) are free for multiple uses: 'a ruling class', 'rules superiority', or 'transcends its sect' so as to avoid circularity. (Rule 2)
The genera and differentia must be applicable to everything to which the defined term applies and nothing else. (Rule 3) This requires a careful examination of each of the small group study examples.
The purpose of a definition is to explain the meaning of a term which may be obscure or difficult, by the use of terms that are commonly understood and whose meaning is clear. (Rule 4) Initially, this appears to be the case, but words leading to a precising definition or theoretical definition may be needed as with Mosby's definition.
The genera differentia definitions are not negative. (Rule 5)
Choosing better relative synonyms may resolve any issues with Rule 3 and Rule 4.

## Kirby's dominant group

Def. groups of insects whose geographical distribution "extends to the tropics, [but] fall short of the polar circles" are called dominant groups.
For two genera ('class' and 'sect') with two differentia ('superior' and 'ruling') there is the following definition.
Def. a class (group) that rules (extends geographical distribution) superiority (tropics to short of the polar circles) and the sect (insects) is called a dominant group.
Here, the core genera differentia meaning of dominant group is isolated.

## Kirby's five conditions

Rule 1: the essential attributes are set out.
Rule 2: 'groups' is an exact synonym for 'group'. There can be a group of groups. 'Extends' is not a relative or exact synonym for 'rules'. 'Tropics to short of the polar circles' is not an exact or relative synonym for 'superiority' but is a value system assigned by Kirby. 'Insect' and 'sect' both mean 'separated' or 'segmented'; i.e., a group of 'separateds' or 'segmenteds'. 'Insect' is not an exact synonym for 'sect' nor is it likely to be considered a relative synonym.
Rule 3: using 'tropics' (Tropic of Capricorn to the Tropic of Cancer) and 'fall short of the polar circles' (Arctic Circle and Antarctic Circle) is an exact geographical extent. Arguments may even be offered using statistics: one ant puts three legs on the polar side of the Arctic Circle while the other three are on the other side may not be statistically significant to say that species of ant has a greater range than a dominant insect group, especially when all the other ants of the species are on the tropics side.
Rule 4: geographical limits such as those used have been commonly understood.
Rule 5: the definition can be written negative but is not.
Kirby's definition of dominant groups of insects is rigorous or can be made such with an application of statistics.

## Economics dominant group

In the economics article cited following: "sect" is used as "section", sections of the article itself, "class" usually refers to a "class of test statistics", "superior" refers to a "superior predictive ability", and "rules" refers to "decision rules" or "trading rules". A definition of dominant group per preceding cited article (only using three of the four genera differentia) may be
Def. a superior class [of test statistics] that [influences] [decision or trading rules] is called a dominant group.
Other definitions are likely. In the above article, the word "dominant" and the term dominant group did not occur.
A second article suggests some other situations. In the citation following, "class" refers to "A majority group, say, the workers, who control the policy might rationally choose to have a constitution which limits their power, say, to expropriate the wealth of the capitalist class.", "the class of feedback policy rules", and "[t]he most general class of decision policies"; "sect" refers to article sections again; "rules" refers to "policy rules" or "decision rules"; and "superior" refers to "Typically the iterative process of the policy rule change inducing investment function change inducing policy rule change, etc., did converge. Given that it converges, the limiting policy rule is consistent in the sense described in Sections I1 and IV. In all cases for which it did converge, we searched for and found linear feedback policy rules which were superior to this consistent rule, typically by a substantial amount." In this article dominant group does not occur but "dominant" does: "dominant player", "dominant firm", and "[f]or policy selection, the policymaker is dominant".
Here a dominant group definition is very similar to the above yet may be
Def. a superior class of [policy or decision] rules is called a dominant group.
These two examples are closer to a genus differentia definition.
A third article is not too different from the first two. Per the following citation: "class" occurs over 100 times in the article and refers to class of stock, as in "superior class of stock", class A shares owned by corporate insiders of top management, class B are the inferior class of stock; "sect" refers again to "section" of the article; "superior" as already indicated; and "rules" refers to takeover rules benefitting the insiders and "voting rules" also benefitting insiders.
Def. a superior class [of stock owned by the corporate insiders] rules [takeover gains and voting for the insiders] is called a dominant group of stock.
Each of the dominant group definitions requires additional words to clarify what's happening; i.e., to make the definition more precise to the specific situations.

## Economics five conditions

For rule 1, with the added terms making each definition more precise, each definition succeeds in setting out the essential attributes of the thing defined. The essential attributes for a dominant group are fulfilled by the superior-class-ruling variations.
Rule 2 requires non-circularity, which is arguably accomplished by the relative synonym "superior class" plus "rules".
Rule 3 may not be met in each example because each is specialized and requires the added terms to be precisely applied, yet what the dominant group consists of and what it is ruling (or how it is ruling) must be specified. While the "rules" on the one hand may be considered a "group of rules" or "set of rules". On the other hand, "rules" do rule.
Rule 4 examination of the three definitions suggests some obscurity, especially without the precising terms. Alternate relative synonyms may make the definitions more relevant.
None of the definitions is negative (rule 5).

## Hypotheses

* Dominant group, like volcano, has been around hominins so long that just about everyone has an intuitive meaning for the two-word term.