But, for the same reason, the laws have not proved an unmixed blessing to psychology. Aristotle, it is clear, was simply raising a practical question; and practical questions are answered in terms of meaning, not of process. Moreover, Aristotle was temperamentally a logician, and he could not help throwing even this bit of everyday practice into formal logical shape. Notice the arrangement in pairs: like-contrary, coexistent-successive; that is logical. Notice also the nature of the pairs. Like-contrary is the extreme way of saying like-unlike; and when you mention succession, you mention the only kind of non-coexistence that can come into account for psychology; so that both pairs have the form ‘A and not-A’ (like and not-like, coexistent and not-coexistent); and that is logical again. _Aristotle’s four rules are therefore not really empirical_, in the sense that they are directly derived from a study of experience; they rather show the inveterate logician, who is bound to schematise and tabulate. Later writers, swayed now by experience and now by logic, have both increased and decreased the number of these ‘laws’ of association; _the general tendency has been to reduce them to two, or even to one_. Thus, we can make contrast, logically, a case of likeness; the palace reminds us of the hovel, apparently by contrast; yet are not the palace and the hovel alike, as human habitations? We can, still more easily, reduce space to time. If the two pictures hung together on the wall, they were seen at the same time. Simultaneity, however, is one kind of contiguity in time; succession is another; and temporal contiguity thus includes everything. The four laws have become two: _similarity, and contiguity in time_. Can we go further? Yes, if we go on arguing. The picture reminded me of Van Eyck; it was _like_ a Van Eyck; the association seems to be an association by similarity. Yet it is practically certain that the picture in question was, at some time or other, present in my mind _along with_ some picture by Van Eyck. It is practically certain, in other words, that the two ideas were in temporal contiguity; and every instance of association by similarity raises the same sort of presumption. That being the case, we may discard the law of similarity; and =contiguity= stands alone, the sole survivor of the Aristotelian quartet. Only, =this is all logic=, a matter of meanings, a translation of psychological fact; we have not got to the facts themselves.