[Footnote 106: The great principle of Herakleitus, which Aristotle states in order to reject (Physic. viii. 3, p. 253, b. 10, [Greek: phasi/ tines kinei=sthai tô=n o)/ntôn ou) ta\ me\n ta\ d' ou), a)lla\ pa/nta kai\ a)ei\; a)lla\ lantha/nein tou=to tê\n ê(mete/ran ai)/sthêsin]) now stands averred in modern physical philosophy. Mr. Grove observes, in his instructive Treatise on the Correlation of Physical Forces, p. 22:
"Of absolute rest, Nature gives us no evidence. All matter, as far as we can discern, is ever in movement: not merely in masses, as in the planetary spheres, but also molecularly, or throughout its intimate structure. Thus every alteration of temperature produces a molecular change throughout the whole substance heated or cooled: slow chemical or electrical forces, actions of light or invisible radiant forces, are always at play; so that, as a fact, we cannot predicate of any portion of matter, that it is absolutely at rest."]
[Footnote 107: Many references to Herakleitus are found in the recently published books of the Refutatio Hæresium by Pseudo-Origen or Hippolytus--especially Book ix. p. 279-283, ed. Miller. To judge by various specimens there given, it would appear that his juxta-positions of contradictory predicates, with the same subject, would be recognised as paradoxes merely in appearance, and not in reality, if we had his own explanation. Thus he says (p. 282) "the pure and the corrupt, the drinkable and the undrinkable, are one and the same." Which is explained as follows: "The sea is most pure and most corrupt: to fish, it is drinkable and nutritive; to men, it is undrinkable and destructive." This explanation appears to have been given by Herakleitus himself, [Greek: tha/lassa, _phêsi\n_], &c.
These are only paradoxes in appearance--the relative predicate being affirmed without mention of its correlate. When you supply the correlate to each predicate, there remains no contradiction at all.]
[Side-note: Empedokles--his doctrine of the four elements, and two moving or restraining forces.]
After Herakleitus, and seemingly at the same time with Parmenides, we arrive at Empedokles (about 500-430 B. C.) and his memorable doctrine of the Four Elements. This philosopher, a Sicilian of Agrigentum, and a distinguished as well as popular-minded citizen, expounded his views in poems, of which Lucretius[108] speaks with high admiration, but of which few fragments are preserved. He agreed with Parmenides, and dissented from Herakleitus and the Ionic philosophers, in rejecting all real generation and destruction.[109] That which existed had not been generated and could not be destroyed. Empedokles explained what that was, which men mistook for generation and destruction. There existed four distinct elements--Earth, Water, Air, and Fire--eternal, inexhaustible, simple, homogeneous, equal, and co-ordinate with each other. Besides these four substances, there also existed two moving forces, one contrary to the other--Love or Friendship, which brought the elements into conjunction--Enmity or Contest, which separated them. Here were alternate and conflicting agencies, either bringing together different portions of the elements to form a new product, or breaking up the product thus formed and separating the constituent elements. Sometimes the Many were combined into One; sometimes the One was decomposed into Many. Generation was simply this combination of elements already existing separately--not the calling into existence of anything new: destruction was in like manner the dissolution of some compound, not the termination of any existent simple substance. The four simple substances or elements (which Empedokles sometimes calls by names of the popular Deities--Zeus, Hêrê, Aidoneus, &c.), were the roots or foundations of everything.[110]