The first duty of radical empiricism, taking given conjunctions at their face-value, is to class some of them as more intimate and some as more external. When two terms are _similar_, their very natures enter into the relation. Being _what_ they are, no matter where or when, the likeness never can be denied, if asserted. It continues predicable as long as the terms continue. Other relations, the _where_ and the _when_, for example, seem adventitious. The sheet of paper may be 'off' or 'on' the table, for example; and in either case the relation involves only the outside of its terms. Having an outside, both of them, they contribute by it to the relation. It is external: the term's inner nature is irrelevant to it. Any book, any table, may fall into the relation, which is created _pro hac vice_, not by their existence, but by their casual situation. It is just because so many of the conjunctions of experience seem so external that a philosophy of pure experience must tend to pluralism in its ontology. So far as things have space-relations, for example, we are free to imagine them with different origins even. If they could get to _be_, and get into space at all, then they may have done so separately. Once there, however, they are _additives_ to one another, and, with no prejudice to their natures, all sorts of space-relations may supervene between them. The question of how things could come to be anyhow, is wholly different from the question what their relations, once the being accomplished, may consist in.