From these considerations we see that objects are said to be related, when there is any fact, simple or complex, either apprehended by the senses or otherwise, in which they both figure. Any objects, whether physical or mental, are related, or are in a relation, to one another, in virtue of any complex state of consciousness into which they both enter; even if it be a no more complex state of consciousness than that of merely thinking of them together. And they are related to each other in as many different ways, or in other words, they stand in as many distinct relations to one another, as there are specifically distinct states of consciousness of which they both form parts. As these may be innumerable, the possible relations not only of any one thing with others, but of any one thing with the same other, are infinitely numerous and various. But they may all be reduced to a certain number of general heads of classification, constituting the different kinds of Relation: each of which requires examination apart, to ascertain what, in each case, the state of consciousness, the cluster or train of sensations or thoughts, really is, in which the two objects figure, and which is connoted by the correlative names. This examination the author accordingly undertakes: and thus, under the guise of explaining names, he analyses all the principal cases which the world and the human mind present, of what are called Relations between things.—Ed.
8 I. The only, or at least the principal, occasions, for naming simple sensations, or simple ideas, in pairs, seem to be these:
1 When we take them into simultaneous view, as such and such;
2. When we take them into simultaneous view, as antecedent and consequent.
II. The principal occasions on which we name the complex ideas, called objects, in pairs, are these four:
9 1. When we speak of them as having an order in space;
2. When we speak of them as having an order in time;
3. When we speak of them as agreeing or disagreeing in quantity;
4. As agreeing or disagreeing in quality.
III. The occasions on which we name the complex ideas of our own formation in pairs, are,