mathematical and theological—Aristotle makes the last the "most excellent,"[14] "for it is conversant about that one amongst entities which is more entitled to respect than the rest."[15] It is to the discussion of this subject in Book XI. that the greater part of the Metaphysics leads up. He has established in the previous portions of the work the two substances which he calls "natural or physical"—namely, matter and form—and now he proceeds to justify the hints he has given of a third substance which is "immovable."[16] It has been customary to divide this discussion of Aristotle into several formal theistic arguments,[17] but in the opinion of the writer the text of the Metaphysics does not lend itself readily to any such cut and dried arrangement of its argument. Aristotle does, indeed, to avoid the absurdity of an endless regress, argue from the κινούμενα and the κινοῦντα of the physical World to a πρῶτον κινοῦν which is a pure ἐνέργεια, ἀκίνητον, ἄνευ ὕλης, and hence foreign to all the passivity and contingency of matter;[18] concludes from motion in the world that there must be a First Mover;[19] and asserts the actuality of the eternal as opposed to potentiality; but these arguments are so blended together, and take each one so much from the others, that I cannot be convinced that Aristotle had ever clearly differentiated them.

But it is clear enough that the crown of Aristotle's whole system is this "prime mover," "unmoved" and "apart from matter," and that this conception, up to which his thought leads from every side, as the necessary implication from the motion everywhere seen in the world, is his chief contribution to the argument for the existence of the Divine. Aristotle's chief interest lay in the cosmological problem, and his form of proof and the result which he reached by it were moulded by this fact. His argument did not lead him to a Creator of the world, for the universe, no less than the prime mover, was eternal, and the latter is nothing more than a principle of reason immanent in the world—pervading it, not distinguished from it—and the author of motion only in a passive way, after all, as a sort of magnetic object of desire.[20] In other places Aristotle makes passing references to different forms of the argument to prove the existence of the gods,[21] but it is evident that his own interest centered around this unmoved final cause, and it is in his proof of its existence from cosmological considerations that his significance for us lies.

In the post-Aristotelian schools we have an entire change of the point of view, and instead of a philosophy of nature, such as occupied the attention of the pre-Socratic thinkers, or a philosophy of mind, such as Socrates, Plato, and to a large extent, Aristotle attempted to construct, we find the interest of men in speculative questions centered in a philosophy of life, of morals. Corresponding to this change in the point of view, we may easily detect an alteration in the manner of dealing with the arguments for the existence of the gods.

There was, in the first place, an increased emphasis laid upon this line of thought, in common with religious subjects in general, and the reasons for the belief in the existence of the gods (for the Greek schools never transcended polytheism—when they speak of θεός they mean simply the abstract divinity of the many separate divinities) seems, so far as we may judge from the comparatively scanty remains that have come down to us, to have been discussed at great length; critically and negatively by the Sceptics, positively and apparently with full conviction by the Stoics, and with a curious mixture of both of these attitudes by the Epicureans. These latter, if the reported doctrine of Epicurus himself be trustworthy, denied the popular gods, and, in order to insure freedom, rejected the Stoic doctrine of providence; but, on the other hand, asserted a belief in gods whose essential characteristics are immortality and perfect happiness (to insure which they must care nothing for the world or for men), and whose existence was held to be proven on the basis of the common consent of all men ("Argumentum e Consensu Gentium"). This argument is the result of a "natural idea" or "pre-notion," which Epicurus called πρόληψις;—"that is, an antecedent conception of the fact in the mind, without which nothing can be understood, inquired after, or discoursed on."[22]

The Stoics, on the other hand, with their strong conviction of providence working in the world, were rather inclined to deny the validity of this argument from common consent, and rested their belief in the gods, as Cicero makes his Stoic do in De Natura Deorum,[23] on the evidence of design and purpose in the universe, but by this process succeeded only in proving to their own satisfaction that the world is divine—a fatalistic pantheism which roused the ire of the Epicurean and Sceptic alike, and which even Cicero seemed hardly to be able to accept.

From this necessarily brief review of the development of the argument for the existence of a Divinity in Greek and Roman thought, it will be seen that, at one time or another, in a more or less fully developed form, each one of the principal types of the theistic argument received the chief emphasis and had its method enunciated. The pre-Socratic natural philosophers, on the basis of the maxim as old as philosophy itself—Ἀδύνατον γίνεσθαι τι ἐκ μηδενὸς προυπάρχοντος— pointed to an Ἀρχή—a real behind phenomena, a permanent behind the change—and thus pointed to the so-called Aetiological argument founded on the principle of causality. Socrates, with his pre-eminently practical disposition and ethical point of view, saw above all things intention in nature, and so from the consideration of this choice and adaptation of means to their end, and the