[30] So far, then, as concerns the efficient Principle this account will suffice for the present. But we must also give a brief account of what are called the Material Principles. ¹ Now that these are inapprehensible may easily be gathered from the disagreement which exists about them amongst the Dogmatists. For Pherecydes of Syros ² declared earth to be the Principle of all things; Thales of Miletus, water; Anaximander (his pupil), the Unlimited; Anaximenes and Diogenes of Apollonia, air; Hippasus of Metapontum, fire; Xenophanes of Colophon, earth and water; Oenopides of Chios, fire and air; Hippo of Rhegium, fire and water; Onomacritus, in his Orphica, fire and water and earth;

[31] the School of Empedocles as well as the Stoics, fire, air, water and earth—for why should one even mention that mysterious ‟indeterminate matter” which some of them talk about, ³ when not even they themselves are positive that they apprehend it? Aristotle the Peripatetic takes as his Principles fire, air, water, earth, and the ‟revolving body;” ⁴

[32] Democritus and Epicurus, atoms; Anaxagoras of Clazomenae, homoeomeries ⁵ ; Diodorus, surnamed Cronos, minimal and non-composite bodies; Heracleides Ponticus and Asclepiades the Bithynian, ⁶ homogeneous masses; the School of Pythagoras, the numbers; the Mathematicians, the limits of bodies; Strato the Physicist, the qualities.

[33] Since, then, there exists amongst them as much divergence as this, and even more, regarding the Material Principles, we shall give assent either to all the positions stated, and all others as well, or to some of them. But to assent to all is not possible; for we certainly shall not be able to assent both to Asclepiades, who says that the elements can be broken up and possess qualities, and to Democritus, who asserts that they are indivisible and void of quality, and to Anaxagoras, who leaves every sensible quality attached to the homoeomeries.

[34] Yet if we shall prefer any one standpoint, or view, to the rest, we shall be preferring it either absolutely and without proof or with proof. ⁷ Now without proof we shall not yield assent; and if it is to be with proof, the proof must be true. But a true proof can only be given when approved by a true criterion, and a criterion is shown to be true by means of an approved proof.

[35] If, then, in order to show the truth of the proof which prefers any one view, its criterion must be proved, and to prove the criterion in turn its proof must be pre-established, the argument is found to be the circular one which will not allow the reasoning to go forward, since the proof keeps always requiring a proved criterion, and the criterion an approved proof.

[36] And should any one propose to approve the criterion by a criterion and to prove the proof by a proof, he will be driven to a regress ad infinitum. Accordingly, if we are unable to assent either to all the views held about the elements or to any one of them, it is proper to suspend judgement about them.

[37] Now though it is, perhaps, possible to show by these arguments alone the inapprehensibility of the elements and of the Material Principles, yet in order that we may be able to refute the Dogmatists in a more comprehensive manner we shall dwell on this topic at appropriate length. And since the opinions about the elements are, as we have shown, numerous and well-nigh infinite, we will excuse ourselves— because of the character of our present treatise— from discussing each opinion in detail, but will make answer to them all implicitly. For since the elements, whatever view one takes of them, must be finally regarded either as corporeal or incorporeal, ⁸ we think it enough to show that corporeal things are inapprehensible and incorporeal things inapprehensible; for thus it will be clear that the elements also are inapprehensible.