Movement of rotation in the mass initiated by Nous on a small scale, but gradually extending itself. Like particles congregate together — distinguishable aggregates are formed.

But though other things could not act upon mind, mind could act upon them. It first originated movement in the quiescent mass. The movement impressed was that of rotation, which first began on a small scale, then gradually extended itself around, becoming more efficacious as it extended, and still continuing to extend itself around more and more. Through the prodigious velocity of this rotation, a separation was effected of those things which had been hitherto undistinguishably huddled together.150 Dense was detached from rare, cold from hot, dark from light, dry from wet.151 The Homœomeric particles congregated together, each to its like; so that bodies were formed — definite and distinguishable aggregates, possessing such a preponderance of some one ingredient as to bring it into clear manifestation.152 But while the decomposition of the multifarious mass was thus carried far enough to produce distinct bodies, each of them specialised, knowable, and regular — still the separation can never be complete, nor can any one thing be “cut away as with a hatchet” from the rest. Each thing, great or small, must always contain in itself a proportion or trace, latent if not manifest, of everything else.153 Nothing except mind can be thoroughly pure and unmixed.

Nothing (except Νοῦς) can be entirely pure or unmixed, but other things may be comparatively pure. Flesh, Bone, &c. are purer than Air or Earth.

Nevertheless other things approximate in different degrees to purity, according as they possess a more or less decided preponderance of some few ingredients over the remaining multitude. Thus flesh, bone, and other similar portions of the animal organism, were (according to Anaxagoras) more nearly pure (with one constituent more thoroughly preponderant and all other coexistent natures more thoroughly subordinate and latent) than the four Empedoklean elements, Air, Fire, Earth, &c.; which were compounds wherein many of the numerous ingredients present were equally effective, so that the manifestations were more confused and complicated. In this way the four Empedoklean elements formed a vast seed-magazine, out of which many distinct developments might take place, of ingredients all pre-existing within it. Air and Fire appeared to generate many new products, while flesh and bone did not.154 Amidst all these changes, however, the infinite total mass remained the same, neither increased nor diminished.155

Theory of Anaxagoras compared with that of Empedokles.

In comparing the theory of Anaxagoras with that of Empedokles, we perceive that both of them denied not only the generation of new matter out of nothing (in which denial all the ancient physical philosophers concurred), but also the transformation of one form of matter into others, which had been affirmed by Thales and others. Both of them laid down as a basis the existence of matter in a variety of primordial forms. They maintained that what others called generation or transformation, was only a combination or separation of these pre-existing materials, in great diversity of ratios. Of such primordial forms of matter Empedokles recognised only four, the so-called Elements; each simple and radically distinct from the others, and capable of existing apart from them, though capable also of being combined with them. Anaxagoras recognised primordial forms of matter in indefinite number, with an infinite or indefinite stock of particles of each; but no one form of matter (except Nous) capable of being entirely severed from the remainder. In the constitution of every individual body in nature, particles of all the different forms were combined; but some one or a few forms were preponderant and manifest, all the others overlaid and latent. Herein consisted the difference between one body and another. The Homœomeric body was one in which a confluence of like particles had taken place so numerous and powerful, as to submerge all the coexistent particles of other sorts. The majority thus passed for the whole, the various minorities not being allowed to manifest themselves, yet not for that reason ceasing to exist: a type of human society as usually constituted, wherein some one vein of sentiment, ethical, æsthetical, religious, political, &c., acquires such omnipotence as to impose silence on dissentients, who are supposed not to exist because they cannot proclaim themselves without ruin.

Suggested partly by the phenomena of animal nutrition.

The hypothesis of multifarious forms of matter, latent yet still real and recoverable, appears to have been suggested to Anaxagoras mainly by the phenomena of animal nutrition.156 The bread and meat on which we feed nourishes all the different parts of our body — blood, flesh, bones, ligaments, veins, trachea, hair, &c. The nutriment must contain in itself different matters homogeneous with all these tissues and organs; though we cannot see such matters, our reason tells us that they must be there. This physiological divination is interesting from its general approximation towards the results of modern analysis.

Chaos common to both Empedokles and Anaxagoras: moving agency, different in one from the other theory.

Both Empedokles and Anaxagoras begin their constructive process from a state of stagnation and confusion both tantamount to Chaos; which is not so much active discord (as Ovid paints it), as rest and nullity arising from the equilibrium of opposite forces. The chaos is in fact almost a reproduction of the Infinite of Anaximander.157 But Anaxagoras as well as Empedokles enlarged his hypothesis by introducing (what had not occurred or did not seem necessary to Anaximander) a special and separate agency for eliciting positive movement and development out of the negative and stationary Chaos. The Nous or Mind is the Agency selected for this purpose by Anaxagoras: Love and Enmity by Empedokles. Both the one and the other initiate the rotatory cosmical motion; upon which follows as well the partial disgregation of the chaotic mass, as the congregation of like particles of it towards each other.

Nous, or mind, postulated by Anaxagoras — how understood by later writers — how intended by Anaxagoras himself.

The Nous of Anaxagoras was understood by later writers as a God;158 but there is nothing in the fragments now remaining to justify the belief that the author himself conceived it in that manner — or that he proposed it (according to Aristotle’s expression159) as the cause of all that was good in the world, assigning other agencies as the causes of all evil. It is not characterised by him as a person — not so much as the Love and Enmity of Empedokles. It is not one but multitudinous, and all its separate manifestations are alike, differing only as greater or less. It is in fact identical with the soul, the vital principle, or vitality, belonging not only to all men and to all plants also.160 It is one substance, or form of matter among the rest, but thinner than all of them (thinner than even fire or air), and distinguished by the peculiar characteristic of being absolutely unmixed. It has moving power and knowledge, like the air of Diogenes the Apolloniate: it initiates movement; and it knows about all the things which either pass into or pass out of combination. It disposes or puts in order all things that were, are, or will be; but it effects this only by acting as a fermenting principle, to break up the huddled mass, and to initiate rotatory motion, at first only on a small scale, then gradually increasing. Rotation having once begun, and the mass having been as it were unpacked and liberated the component Homœomeries are represented as coming together by their own inherent attraction.161 The Anaxagorean Nous introduces order and symmetry into Nature, simply by stirring up rotatory motion in the inert mass, so as to release the Homœomeries from prison. It originates and maintains the great cosmical fact of rotatory motion; which variety of motion, from its perfect regularity and sameness, is declared by Plato also to be the one most consonant to Reason and Intelligence.162 Such rotation being once set on foot, the other phenomena of the universe are supposed to be determined by its influence, and by their own tendencies and properties besides: but there is no farther agency of Nous, which only knows these phenomena as and when they occur. Anaxagoras tried to explain them as well as he could; not by reference to final causes, nor by assuming good purposes of Nous which each combination was intended to answer — but by physical analogies, well or ill chosen, and especially by the working of the grand cosmical rotation.163

Plato and Aristotle blame Anaxagoras for deserting his own theory.

This we learn from Plato and Aristotle, who blame Anaxagoras for inconsistency in deserting his own hypothesis, and in invoking explanations from physical agencies, to the neglect of Nous and its supposed optimising purposes. But Anaxagoras, as far as we can judge by his remaining fragments, seems not to have committed any such inconsistency. He did not proclaim his Nous to be a powerful extra-cosmical Architect, like the Demiurgus of Plato — nor an intra-cosmical, immanent, undeliberating instinct (such as Aristotle calls Nature), tending towards the production and renewal of regular forms and conjunctions, yet operating along with other agencies which produced concomitants irregular, unpredictable, often even obstructive and monstrous. Anaxagoras appears to conceive his Nous as one among numerous other real agents in Nature, material like the rest, yet differing from the rest as being powerful, simple, and pure from all mixture,164 as being endued with universal cognizance, as being the earliest to act in point of time, and as furnishing the primary condition to the activity of the rest by setting on foot the cosmical rotation. The Homœomeries are coeternal with, if not anterior to, Nous. They have laws and properties of their own, which they follow, when once liberated, without waiting for the dictation of Nous. What they do is known by, but not ordered by, Nous.165 It is therefore no inconsistency in Anaxagoras that he assigns to mind one distinct and peculiar agency, but nothing more; and that when trying to explain the variety of phenomena he makes reference to other physical agencies, as the case seems to require.166

Astronomy and physics of Anaxagoras.

In describing the formation of the Kosmos, Anaxagoras supposed that, as a consequence of the rotation initiated by mind, the primitive chaos broke up. “The Dense, Wet, Cold, Dark, Heavy, came together into the place where now Earth is: Hot, Dry, Bare, Light, Bright, departed to the exterior region of the revolving Æther.”167 In such separation each followed its spontaneous and inherent tendency. Water was disengaged from air and clouds, earth from water: earth was still farther consolidated into stones by cold.168 Earth remained stationary in the centre, while fire and air were borne round it by the force and violence of the rotatory movement. The celestial bodies — Sun, Moon, and Stars — were solid bodies analogous to the earth, either caught originally in the whirl of the rotatory movement, or torn from the substance of the earth and carried away into the outer region of rotation.169 They were rendered hot and luminous by the fiery fluid in the rapid whirl of which they were hurried along. The Sun was a stone thus made red-hot, larger than Peloponnesus: the Moon was of earthy matter, nearer to the Earth, deriving its light from the Sun, and including not merely plains and mountains, but also cities and inhabitants.170 Of the planetary movements, apart from the diurnal rotation of the celestial sphere, Anaxagoras took no notice.171 He explained the periodical changes in the apparent course of the sun and moon by resistances which they encountered, the former from accumulated and condensed air, the latter from the cold.172 Like Anaximenes and Demokritus, Anaxagoras conceived the Earth as flat, round in the surface, and not deep, resting on and supported by the air beneath it. Originally (he thought) the earth was horizontal, with the axis of celestial rotation perpendicular, and the north pole at the zenith, so that this rotation was then lateral, like that of a dome or roof; it was moreover equable and unchanging with reference to every part of the plane of the earth’s upper surface, and distributed light and heat equally to every part. But after a certain time the Earth tilted over of its own accord to the south, thus lowering its southern half, raising the northern half, and causing the celestial rotation to appear oblique.173

His geology, meteorology, physiology.

Besides these doctrines respecting the great cosmical bodies, Anaxagoras gave explanations of many among the striking phenomena in geology and meteorology — the sea, rivers, earthquakes, hurricanes, hail, snow, &c.174 He treated also of animals and plants — their primary origin, and the manner of their propagation.175 He thought that animals were originally produced by the hot and moist earth; but that being once produced, the breeds were continued by propagation. The seeds of plants he supposed to have been originally contained in the air, from whence they fell down to the warm and moist earth, where they took root and sprung up.176 He believed that all plants, as well as all animals, had a certain measure of intelligence and sentiment, differing not in kind but only in degree from the intelligence and sentiment of men; whose superiority of intelligence was determined, to a great extent, by their possession of hands.177 He explained sensation by the action of unlike upon unlike (contrary to Empedokles, who referred it to the action of like upon like),178 applying this doctrine to the explanation of the five senses separately. But he pronounced the senses to be sadly obscure and insufficient as means of knowledge. Apparently, however, he did not discard their testimony, nor assume any other means of knowledge independent of it, but supposed a concomitant and controlling effect of intelligence as indispensable to compare and judge between the facts of sense when they appeared contradictory.179 On this point, however, it is difficult to make out his opinions.

The doctrines of Anaxagoras were regarded as offensive and impious.

Anaxagoras, residing at Athens and intimately connected with Perikles, incurred not only unpopularity, but even legal prosecution, by the tenor of his philosophical opinions, especially those on astronomy. To Greeks who believed in Helios and Selênê as not merely living beings but Deities, his declaration that the Sun was a luminous and fiery stone, and the Moon an earthy mass, appeared alike absurd and impious. Such was the judgment of Sokrates, Plato, and Xenophon, as well as of Aristophanes and the general Athenian public.180 Anaxagoras was threatened with indictment for blasphemy, so that Perikles was compelled to send him away from Athens.

That physical enquiries into the nature of things, and attempts to substitute scientific theories in place of the personal agency of the Gods, were repugnant to the religious feelings of the Greeks, has been already remarked.181 Yet most of the other contemporary philosophers must have been open to this reproach, not less than Anaxagoras; and we learn that the Apolloniate Diogenes left Athens from the same cause. If others escaped the like prosecution which fell upon Anaxagoras, we may probably ascribe this fact to the state of political party at Athens, and to the intimacy of the latter with Perikles. The numerous political enemies of that great man might fairly hope to discredit him in the public mind — at the very least to vex and embarrass him — by procuring the trial and condemnation of Anaxagoras. Against other philosophers, even when propounding doctrines not less obnoxious respecting the celestial bodies, there was not the same collateral motive to stimulate the aggressive hostility of individuals.

Diogenes of Apollonia recognises one primordial element.

Contemporary with Anaxagoras — yet somewhat younger, as far as we can judge, upon doubtful evidence — lived the philosopher Diogenes, a native of Apollonia in Krete. Of his life we know nothing except that he taught during some time at Athens, which city he was forced to quit on the same ground as Anaxagoras. Accusations of impiety were either brought or threatened against him:182 physical philosophy being offensive generally to the received religious sentiment, which was specially awakened and appealed to by the political opponents of Perikles.