Bibliography

Book II. Division I. Part 2. Logic of Relatives. Chapter XII. The Algebra of Relatives

A fact is an element of truth expressible as a proposition.

The scholastic doctors used to talk of first intentions and second intentions. First intentions were conceptions obtained by generalizing ordinary experiences. Second intentions were conception[s] obtained by generalizing conceptions themselves considered as objects of logical comparison.

As all of logic deals with relations, it is more accurate to describe the branch of logic with which I am going to expound as the logic of relatives, i.e. relative terms. Relations as relatives are either dual, as in “A loves B” or plural, as “A gives B to C”.

A relation is precisely defined as a fact about several subjects. A fact is an element of truth expressible as a proposition.

The scholastic doctors used to talk of first intentions and second intentions. First intentions were conceptions obtained by generalizing ordinary experiences. Second intentions were conception[s] obtained by generalizing conceptions themselves considered as objects of logical comparison. Now an abstract notion, that is, the name of a quality, is the first fruit of second-intentional thought.

The scholastic doctors used to talk of first intentions and second intentions. First intentions were conceptions obtained by generalizing ordinary experiences. Second intentions were conception[s] obtained by generalizing conceptions themselves considered as objects of logical comparison. Now an abstract notion, that is, the name of a quality, is the first fruit of second-intentional thought. I have therefore called that branch of formal logic which takes account of this operation, and expresses it, Second Intentional Logic.