Relations Complex ideas of relations derive from the mental...

Relations Complex ideas of relations derive from the mental operation of comparing distinct ideas without thereby combining them together into an entirely new whole. [Essay II xii 1, 7] Since this comparison considers each of the ideas in light of its extrinsic conformity with the other, it is commonly expressed by means of one of a pair of reciprocal relative terms-"parent"/"child" or "cause"/"effect," for example.

This is not invariably the case, however, so we must be alert to the possibility that apparently positive terms implicitly signify comparison with something else: "old" or "imperfect," for example. The tip-off to such cases, on Locke's view, is that (as in the case of relations of the other sort) removal of the correlative destroys the relation completely, rendering the term inapplicable.

[Essay II xxv] Many of our ideas of relations are acquired through sensory experience of the modes of time, place, and number. The correlative ideas of cause and effect are a special instance, on Locke's view: observing the changes produced in one thing by the operation of another, we form a sensitive notion of the causal relation even though we have no conception of the underlying mechanism at all.

[Essay II xxvi 1-6] Because language is devised for our convenience in satisfying the needs of ordinary life, things that are commonly connected in observation give rise to our complex ideas of natural relations. But we also conceive of instituted or voluntary relations between things that are corrleated with each other only by virtue of our own personal or social agreements.

Among these, on Locke's view, the most important and vital are the moral relations drawn between the complex ideas of specific human actions, together with their circumstances and goals, and the moral rules by reference to which we evaluate them. [Essay II xxviii 1-4] We'll look at these much more closely later on. Substances According to Locke, the complex idea of a substance is a collection of simple ideas that is believed capable of existing independently.

Observing in experience that several features recur together frequently, we suppose that there must be some common subject that has all of them.