Part 3

The first words of this argument deserve particular attention, "Si la terre suit le mouvement de l'axe du monde." Here we have an exact recital of the doctrine proclaimed by the Platonic Timæus, and ascribed to him by Aristotle (quite different from the doctrine "que la terre tourne sur elle-même"). M. Cousin here speaks very distinctly about the cosmical axis, and about its movement; thus implying that Plato conceived it as a solid revolving cylinder. This, in my judgment, is the most essential point for clearing up the question in debate. The cosmical axis being of this character, when Plato affirms that the earth is _packed or fastened round it_ (_se roule_--Cousin: _se serre et s'enroule_--Martin: _drängt sich, macht eine Kugel um ihn_--Buttmann), I maintain that, in the plainest construction of the word, the earth does and must follow the movement of the axis--or arrest the movement of the axis. The word [Greek: ei(lome/nên] or [Greek: i)llome/nên] has no distinct meaning at all, if it does not mean this. The very synonyms ([Greek: sphiggome/nên, peridedeme/nên], &c.), which the commentators produce to prove that Plato describes the earth as at rest, do really prove that he describes it as rotating round and with the cosmical axis. We ought not to be driven from this plain meaning of the word, by the assurance of M. Cousin and others that Plato cannot have meant so, because it would involve him in an astronomical inconsistency.

4. "Les divers mouvemens des huit sphères expliquent toutes les apparences célestes; il n'y a donc aucune raison pour donner un mouvement à la terre."

The terms of this fourth argument, if literally construed, would imply that Plato had devised a complete and satisfactory astronomical theory. I pass over this point, and construe them as M. Cousin probably intended: his argument will then stand thus--"The movement of the earth does not add anything to Plato's power of explaining astronomical appearances; therefore Plato had no motive to suggest a movement of the earth."

I have already specified the sense in which I understand the Platonic Timæus to affirm, or rather to imply, the rotation of the earth; and that sense is not open to the objections raised in M. Cousin's fourth and fifth arguments. The rotation of the earth, as it appears in the Platonic Timæus, explains nothing, and is not intended to explain anything. It is a consequence, not a cause: it is a consequence arising from the position of the earth, as packed or fastened round the centre of the cosmical axis, whereby the earth participates, of necessity and as a matter of course, in the movements of that axis. The _function_ of the earth, thus planted in the centre of the kosmos, is to uphold and regulate the revolutions of the cosmical axis; and this function explains, in the scheme of the Platonic Timæus, why the axis revolves uniformly and constantly without change or displacement. Now upon these revolutions of the cosmical axis all the revolutions of the exterior sphere depend. This is admitted by M. Cousin himself in argument 3. There is therefore every reason why Plato should assign such regulating function to the earth, the "first and oldest of intra-kosmic deities." The movement of the earth (as I before observed) is only an incidental consequence of the position necessary for the earth to occupy in performing such function.

5. "Enfin Platon assigne un mouvement aux étoiles fixes, et deux mouvemens aux planètes; puisqu'il ne range la terre ni avec les unes ni avec les autres, il y a lieu de croire qu'elle ne participe à aucun de leurs mouvemens."

In so far as this argument is well-founded, it strengthens my case more than that of M. Cousin. The earth does not participate in the movements either of the fixed stars or of the planets; but it does participate in the revolutions of the cosmical axis, upon which these movements depend--the movements of the outer sphere, wholly and exclusively--the movements of the planets, to a very great degree, but not exclusively. The earth is not ranked either among the fixed stars or among the planets; it is a body or deity _sui generis_, having a special central function of its own, to regulate that cosmical axis which impels the whole system. The earth has a motion of its own, round and along with the cosmical axis to which it is attached; but this motion of the earth (I will again repeat, to prevent misapprehension) is a fact not important by itself, nor explaining anything. The grand and capital fact is the central position and regulating function of the earth, whereby all the cosmical motions, first those of the axis, next those of the exterior kosmos, are upheld and kept uniform.

M. Cousin adds, as a sixth argument:--

"On peut ajouter à ces raisons que Platon aurait nécessairement insisté sur le mouvement de la terre, s'il l'avait admis; et que ce point étoit trop controversé de son temps et trop important en lui-même, pour qu'il ne fît que l'indiquer en se servant d'une expression équivoque."

In the first place, granting Plato to have believed in the motion of the earth, can we also assume that he would necessarily have asserted it with distinctness and emphasis, as M. Cousin contends? I think not. Gruppe maintains exactly the contrary; telling us that Plato's language was intentionally obscure and equivocal--from fear of putting himself in open conflict with the pious and orthodox sentiment prevalent around him. I do not carry this part of the case so far as Gruppe, but I admit that it rests upon a foundation of reality. When we read (Plutarch, De Facie in Orbe Lunæ, p. 923) how the motion of the earth, as affirmed by Aristarchus of Samos (doubtless in a far larger sense than Plato ever imagined, including both rotation and translation), was afterwards denounced as glaring impiety, we understand the atmosphere of religious opinion with which Plato was surrounded. And we also perceive that he might have reasons for preferring to indicate an astronomical heresy in terms suitable for philosophical hearers, rather than to proclaim it in such emphatic unequivocal words, as might be quoted by some future Melêtus in case of an indictment before the Dikasts.

We must remember that Plato had been actually present at the trial of Sokrates. He had heard the stress laid by the accusers on astronomical heresies, analogous to those of Anaxagoras, which they imputed to Sokrates--and the pains taken by the latter to deny that he held such opinions (see the Platonic Apology). The impression left by such a scene on Plato's mind was not likely to pass away: nor can we be surprised that he preferred to use propositions which involved and implied, rather than those which directly and undisguisedly asserted, the heretical doctrine of the earth's rotation. That his phraseology, however indirect, was perfectly understood by contemporary philosophers, both assentient and dissentient, as embodying his belief in the doctrine--is attested by the two passages of Aristotle.

Upon these reasons alone I should dissent from M. Cousin's sixth argument. But I have other reasons besides. He rests it upon the two allegations that the doctrine of the earth's motion was the subject of much controversial debate in Plato's time, and of great importance in itself. Now the first of these two allegations can hardly be proved, as to the time of Plato; for Aristotle, when he is maintaining the earth's immobility, does not specify any other opponents than the Pythagoreians and the followers of the Platonic Timæus. And the second allegation I believe to be unfounded, speaking with reference to the Platonic Timæus. In the cosmical system therein embodied, the rotation of the earth round the cosmical axis, though a real part of the system, was in itself a fact of no importance, and determining no results. The capital fact of the system was the position and function of the earth, packed close round the centre of the cosmical axis, and regulating the revolutions of that axis. Plato had no motive to bring prominently forward the circumstance that the earth revolved itself along with the cosmical axis, which circumstance was only an incidental accompaniment.

I have thus examined all the arguments adduced by M. Cousin, and have endeavoured to show that they fail in establishing his conclusion. There is, however, one point of the controversy in which I concur with him more than with Boeckh and Martin. This point is the proper conception of what Plato means by the _cosmical axis_. Boeckh and Martin seem to assume this upon the analogy of what is now spoken of as the axis of the earth: M. Boeckh (p. 13) declares the axis of the kosmos to be a prolongation of that axis. But it appears to me (and M. Cousin's language indicates the same) that Plato's conception was something very different. The axis of the earth (what astronomers speak of as such) is an imaginary line traversing the centre of the earth; a line round which the earth revolves. Now the cosmical axis, as Plato conceives it, is a solid material cylinder, which not only itself revolves, but causes by this revolution the revolution of the exterior circumference of the kosmos. This is a conception entirely different from that which we mean when we speak of the axis of the earth. It is, however, a conception symbolically enunciated in the tenth book of the Republic, where the spindle of Necessity is said to be composed of adamant, hard and solid material, and to cause by its own rotation the rotation of all the _verticilli_ packed and fastened around it. What is thus enunciated in the Republic is implied in the Timæus. For when we read therein that the earth is packed or fastened round the cosmical axis, how can we understand it to be packed or fastened round an imaginary line? I will add that the very same meaning is brought out in the translation of Cicero--"_trajecto axe sustinetur_" (terra). The axis, round which the earth is fastened, and which sustains the earth, must be conceived, not as an imaginary line, but as a solid cylinder, itself revolving; while the earth, being fastened round it, revolves round and along with it. The axis, in the sense of an imaginary line, cannot be found in the conception of Plato.

Those contemporaries of Plato and Aristotle, who all agreed in asserting the revolution of the celestial sphere, did not all agree in their idea of the force whereby such revolution was brought about. Some thought that the poles of the celestial sphere exercised a determining force: others symbolised the mythical Atlas, as an axis traversing the sphere from pole to pole and turning it round. (Aristotel. De Motu Animal. 3. p. 699 a. 15-30.) Aristotle himself advocated the theory of a _primum movens immobile_ acting upon the sphere from without the sphere. Even in the succeeding centuries, when astronomy was more developed, Aratus, Eratosthenes, and their commentators, differed in their way of conceiving the cosmical axis. Most of them considered it as solid: but of these, some thought it was stationary, with the sphere revolving round it--others that it revolved itself: again, among these latter, some believed that the revolutions of the axis determined those of the surrounding sphere--others, that the revolutions of the sphere caused those of the axis within it. Again, there were some physical philosophers who looked at the axis as airy or spiritual--[Greek: to\ dia\ me/sou tê=s sphai/ras diê=kon pneu=ma]. Then there were geometers who conceived it only as an imaginary line. (See the Phaenomena of Aratus 20-25--with the Scholia thereon; Achilles Tatius ad Arati Phaenom. apud Petavium--Uranolog. p. 88; also Hipparchus ad Arat. ib. p. 144.) I do not go into these dissentient opinions farther than to show, how indispensable it is, when we construe the passage in the Platonic Timaeus, [Greek: peri\ to\n dia\ panto\s po/lon tetame/non], to enquire in what sense Plato understood the cosmical axis: and how unsafe it is to assume at once that he must have conceived it as an imaginary line.

Proklus argues that because the earth is mentioned by Plato in the Phædon as stationary in the centre of the heaven, we cannot imagine Plato to affirm its rotation in the Timæus. I agree with M. Boeckh in thinking this argument inconclusive; all the more, because, in the Phædon, not a word is said either about the axis of the kosmos, or about the rotation of the kosmos; all that Sokrates professes to give is [Greek: tê\n i)de/an tê=s gê=s kai\ tou\s to/pous au)tê=s**] (p. 108 E). No cosmical system or theory is propounded in that dialogue.

When we turn to the Phædrus, we find that, in its highly poetical description, the rotation of the heaven occupies a prominent place. The internal circumference of the heavenly sphere, as well as its external circumference or back ([Greek: nô=ton]), are mentioned; also its periodical rotations, during which the gods are carried round on the back of the heaven, and contemplate the eternal Ideas occupying the super-celestial space (p. 247, 248), or the plain of truth.[5] But the purpose of this poetical representation appears to be metaphysical and intellectual, to illustrate the antithesis presented by the world of Ideas and Truth on one side--against that of sense and appearances on the other. Astronomically and cosmically considered, no intelligible meaning is conveyed. Nor can we even determine whether the rotations of the heaven, alluded to in the Phædrus, are intended to be diurnal or not; I incline to believe not ([Greek: me/chri tê=s _e(te/ras_ perio/dou]--p. 248--which can hardly be understood of so short a time as one day). Lastly, nothing is said in the Phædrus about the cosmical axis; and it is upon this that the rotations of the earth intimated in the Timæus depend.

[Footnote 5: Whether [Greek: E)sti/a] in the Phædrus, which is said "to remain alone stationary in the house of the Gods," can be held to mean the Earth, is considered by Proklus to be uncertain (p. 681).]

Among the different illustrations, given by Plato in his different dialogues respecting the terrestrial and celestial bodies, I select the tenth book of the Republic as that which is most suitable for comparison with the Timæus, because it is only therein that we learn how Plato conceived the axis of the kosmos. M. Boeckh (Untersuchungen, p. 86) wishes us to regard the difference between the view taken in the Phædon, and that in the Republic, as no way important; he affirms that the adamantine spindle in the Republic is altogether mythical or poetical, and that Plato conceives the axis as not being material. On this point I dissent from M. Boeckh. The mythical illustrations in the tenth book of the Republic appear to me quite unsuitable to the theory of an imaginary, stationary, and immaterial axis. Here I much more agree with Gruppe (p. 15, 26-29), who recognises the solid material axis as an essential feature of the cosmical theory in the Republic; and recognises also the marked difference between that theory and what we read in the Phædon. Yet, though Gruppe is aware of this important difference between the Republic and the Phædon, he still wishes to illustrate the Timæus by the latter and not by the former. He affirms that the earth in the Timæus is conceived as unattached, and freely suspended, the same as in the Phædon; but that in the Timæus it is conceived, besides, as revolving on its own axis, which we do not find in the Phædon (p. 28, 29). Here I think Gruppe is mistaken. In construing the words of Timæus, [Greek: ei(lome/nên (i)llome/nên) peri\ to\n dia\ panto\s po/lon tetame/non], as designating "the unattached earth revolving round its own axis," he does violence not less to the text of Plato than to the expository comment of Aristotle. Neither in the one nor the other is anything said about _an axis of the earth_; in both, the cosmical axis is expressly designated; and, if Gruppe is right in his interpretation of [Greek: ei(lome/nên], we must take Plato as affirming, not that the earth is fastened round the cosmical axis, but that it revolves, though unattached, around that axis, which is a proposition both difficult to understand, and leading to none of those astronomical consequences with which Gruppe would connect it. Again, when Gruppe says that [Greek: ei(lome/nên peri\] does _not_ mean _packed or fastened round_, but that it _does_ mean _revolving round_, he has both the analogies of the word and the other commentators against him. The main proof, if not the only proof, which he brings, is that Aristotle so construed it. Upon this point I join issue with him. I maintain that Aristotle does _not_ understand [Greek: ei(lome/nên] or [Greek: i)llome/nên peri\] as naturally meaning _revolving round_, and that he does understand the phrase as meaning _fastened round_. When we find him, in the second passage of the treatise De Coelo, not satisfied with the verb [Greek: i)/llesthai] alone, but adding to it the second verb [Greek: _kai\ kinei=sthai_], we may be sure that he did not consider [Greek: i)/llesthai] as naturally and properly denoting _to revolve_ or _move round_.

Agreeing as I do with Gruppe in his view, that the interpretation put by Aristotle is the best evidence which we can follow in determining the meaning of this passage in the Timæus, I contend that the authority of Aristotle contradicts instead of justifying the conclusion at which he arrives. Aristotle understands [Greek: i)llome/nên] as meaning _packed or fastened round_; he does not understand it as meaning, when taken by itself, _revolving round_.

The two meanings here indicated are undoubtedly distinct and independent. But they are not for that reason contradictory and incompatible. It has been the mistake of critics to conceive them as thus incompatible; so that if one of the two were admitted, the other must be rejected. I have endeavoured to show that this is not universally true, and that there are certain circumstances in which the two meanings not only may come together, but must come together. Such is the case when we revert to Plato's conception of the cosmical axis as a solid revolving cylinder. That which is packed or fastened around the cylinder must revolve around it, and along with it.

Both M. Boeckh and Gruppe assume the incompatibility of the two meanings; and we find the same assumption in Plutarch's criticisms on the Timæus (Plutarch. Quæst. Platon. p. 1006 C), where he discusses what Plato means by [Greek: o)/rgana chro/nou]; and in what sense the earth as well as the moon can be reckoned as [Greek: o)/rganon chro/nou] (Timæus, p. 41 E, 42 D). Plutarch inquires how it is possible that the earth, if stationary and at rest, can be characterised as "among the instruments of time;" and he explains it by saying that this is true in the same sense as we call a gnomon or sun-dial an instrument of time, because, though itself never moves, it marks the successive movements of the shadow. This explanation might be admissible for the phrase [Greek: o)/rganon chro/nou]; but I cannot think that the immobility of the earth can be made compatible with the attribute which Plato bestows upon it of being [Greek: phu/lax kai\ _dêmiourgo\s_ nukto\s te kai\ ê(me/ras].

The difficulty, however, vanishes when we understand the function ascribed by Plato to the earth as I have endeavoured to elucidate it. The earth not only is not at rest, but cannot be at rest, precisely because it is packed round the solid revolving cosmical axis, and must revolve along with it. The function of the earth, as the first and oldest of intra-kosmic deities, is to uphold and regulate the revolutions of this axis, upon which depend the revolutions of the sidereal sphere or outer shell of the kosmos. It is by virtue of this regulating function (and not by virtue of its rotation) that the earth is the guardian and artificer of night and day. It is not only "an instrument of time," but the most potent and commanding among all instruments of time.

What has just been stated is, in my belief, the theory of the Platonic Timæus, signified in the words of that dialogue, and embodied in the comment of Aristotle. The commentators, subsequent to Aristotle, so far as we know them, understood the theory in a sense different from what Plato intended. I think we may see how this misconception arose. It arose from the great development and elaboration of astronomical theory during the two or three generations immediately succeeding Plato. Much was added by Eudoxus and others, in their theory of concentric spheres: more still by others of whom we read in Cicero (Academ. II. 39.) "Hicetas Syracusius, ut ait Theophrastus, coelum, solem, lunam, stellas, supera denique omnia, stare censet, neque praeter terram rem ullam in mundo moveri: quae cum circum axem se summâ celeritate convertat et torqueat, eadem effici omnia, quae si stante terrâ coelum moveretur. Atque hoc etiam Platonem in Timaeo dicere quidam arbitrantur, sed paullo obscurius." The same doctrine is said to have been held by Herakleides of Pontus, the contemporary of Aristotle, and by others along with him. (Simplikius ad Aristot. Physic. p. 64--De Coelo, p. 132--Plutarch. Plac. Phil. III. 13.) The doctrine of the rotation of the Earth here appears along with another doctrine--the immobility of the sidereal sphere and of the celestial bodies. The two are presented together, as correlative portions of one and the same astronomical theory. There are no celestial revolutions, and therefore there is no solid celestial axis. Moreover, even Aristarchus of Samos (who attained to a theory substantially the same as the Copernican, with the double movement of the Earth, rotation round its own axis, and translation round the sun as a centre) comes within less than a century after Plato's death.

Though the _quidam_ alluded to by Cicero looked upon the obscure sentence in Plato's Timaeus as a dim indication of the theory of Hicetas, yet the two agree only in the supposition of a rotation of the earth, and differ essentially in the pervading cosmical conceptions. Hicetas states distinctly that which his theory denies, as well as that which it affirms. The negation of the celestial rotations, is in his theory a point of capital and coordinate importance, on which he contradicts both Plato and Aristotle as well as the apparent evidence of sense. I cannot suppose that this theory can have been proclaimed or known to Aristotle when his works were composed: for the celestial revolutions are the keystone of his system, and he could hardly have abstained from combating a doctrine which denied them altogether. In the hands of Hicetas (perhaps in those of Herakleides, if we may believe what is said about him) astronomy appears treated as a science by itself, with a view "to provide such hypotheses as may save the phenomena" ([Greek: sô/zein ta\ phaino/mena], Simpl. ad Aristot. De Coelo, p. 498, Schol. Brandis). It becomes detached from those religious, ethical, poetical, teleological, arithmetical decrees or fancies, in which we see it immersed in the Platonic Timaeus, and even (though somewhat less) in the Aristotelian Treatise De Coelo. Hence the meaning of Plato, obscurely announced from the beginning, ceased to be understood: the solid revolving axis of the Kosmos, assumed without being expressly affirmed in his Timaeus, dropped out of sight: the doctrine of the rotation of the earth was presented in a new point of view, as a substitute for the celestial revolutions. But no proper note was taken of this transition. The doctrine of Plato was assumed to be the same as that of Hicetas.