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Dyadic Relation

1897 | The Logic of Relatives | CP 3.535

…a dyadic relation […] is nothing but an aggregation of pairs. Now any two hecceities may in either order form a pair; and any aggregate whatever of such pairs will form *some* dyadic relation. Hence, we may totally disregard the manner in which the hecceities are connected in determining the possibility of a hypothesis about *some* dyadic relation.

1897 [c.] | Recreations in Reasoning | CP 4.154

A fact true of a pair of subjects […] is a “dyadic relation.”

1897 [c.] | On Multitude | MS [R] 26:8

A *dyadic relation* is a predicate of an ordered pair of subjects, of which one, the grammatical subject, is called the *relate*, and the other, the grammatical object[,] is called the *correlate*.

1902 | Logic (exact) | DPP 2:27; CP 3.625

*Dyadic relation*. A fact relating to two individuals. Thus, the fact that *A* is similar to *B*, and the fact that *A* is a lover of *B*, and the fact that *A* and *B* are both men, are dyadic relations; while the fact that *A* gives *B* to *C* is a triadic relation. Every relation of one order of relativity may be regarded as a relative of another order of relativity if desired. Thus, *man* may be regarded as *man coexistent with*, and so as a relative expressing a dyadic relation, although for most purposes it will be regarded as a monad or non-relative term.

1903 | Nomenclature and Divisions of Dyadic Relations | CP 3.571-572

A *dyadic relation* is a character whose being consists in the logical possibility of a definite fact concerning an ordered pair, or *dyad*, of subjects; the first of these being termed the *relate*, the second the *correlate*; and the relation is said to *subsist* between the relate and correlate when the fact in whose possibility its being consists actually has place between these objects. The relation, by itself, is, therefore, an *ens rationis* and mere logical possibility; but its subsistence is of the nature of a fact. [—]

The broadest division of dyadic relations is into those which can only subsist between two subjects of different categories of being (as between an existing individual and a quality) and those which can subsist between two subjects of the same category. A relation of the former kind may advantageously be termed a *reference*; a relation of the latter kind, a *dyadic relation proper*.

1905-07 [c.] | Considerations concerning the Doctrine of Multitude | MS [R] 27:5

A dyadic relation is a genaral character of *dyads*, or ordered pairs. [—] A genuine dyadic relation is one which does not consist in the two members of any dyad between which it subsists having certain qualities.

1912 | Notes Preparatory to a Criticism of Bertrand Russell's Principles of Mathematics | MS [R] 12:5

By a “dyadic relation” I mean a predicate applicable to two subjects, usually independent.