Part 2

Hence we may plainly see that Aristotle probably did not see the incompatibility, supposed to be so glaring, upon which M. Boeckh's argument is founded. To say the least, even if he saw it, he did not consider it as glaring and decisive. He would have put it in the foreground of his refutation, if he had detected the gross contradiction upon which M. Boeckh insists. But Aristotle does not stand alone in this dulness of vision. Among the various commentators, ancient and modern, who follow him, discussing the question now before us, not one takes notice of M. Boeckh's argument. He himself certifies to us this fact, claiming the argument as his own, and expressing his astonishment that all the previous critics had passed it over, though employing other reasons much weaker to prove the same point. We read in M. Boeckh's second 'Commentatio de Platonico Systemate Coelestium Globorum et de Verâ Indole Astronomiæ Philolaicæ,' Heidelberg, 1810, p. 9, the following words:--

"Non moveri tellurem, Proclus et Simplicius ostendunt ex Phædone. Parum firmum tamen argumentum est ex Phædone ductum ad interpretandum Timæi locum: nec melius alterum, quod Locrus Timæus, quem Plato sequi putabatur, terram stare affirmat: quia, ut nuper explicuimus, non Plato ex Locro, sed personatus Locrus ex Platone, sua compilavit. At omnium firmissionum et certissimum argumentum ex ipso nostro dialogo sumptum, adhuc, quod jure mirere, nemo reperit. Etenim, quum, paulo supra, orbem stellarum fixarum, quem Græci [Greek: a)planê=] appellant, dextrorsum ferri quotidiano motu Plato statuebat, non poterat ullum terræ motum admittere; quia, qui hunc admittit, illum non tollere non potest." (This passage appears again cited by M. Boeckh himself in his more recent dissertation 'Untersuchungen über das kosmische System des Platon,' p. 11). The writers named (p. 7) as having discussed the question, omitting or disregarding this most cogent argument, are names extending from Aristotle down to Ruhnken and Ideler.

It is honourable to the penetration of M. Boeckh that he should have pointed out, what so many previous critics had overlooked, that these two opinions are scientifically incompatible. He wonders, and there may be good ground for wondering, how it happened that none of these previous writers were aware of the incompatibility. But the fact that it did not occur to them, is not the less certain, and is of the greatest moment in reference to the question now under debate; for we are not now inquiring what is or is not scientifically true or consistent, but what were the opinions of Plato. M. Boeckh has called our attention to the fact, that these two opinions are incompatible; but can we safely assume that Plato must have perceived such incompatibility between them? Surely not. The Pythagoreans of his day did not perceive it; their cosmical system included both the revolution of the earth and the revolution of the sidereal sphere round the central fire, ten revolving bodies in all (Aristotel. Metaphysic. i. 35, p. 96 a. 10. De Coelo, ii. 13, p. 293 b. 21). They were not aware that the revolutions of the one annulled those of the other as to effect, and that their system thus involved the two contradictory articles, or "mélange monstrueux," of which Martin speaks so disdainfully. Nay, more, their opponent, Aristotle, while producing other arguments against them, never points out the contradiction. Since it did not occur to them, we can have no greater difficulty in believing that neither did it occur to Plato. Indeed, the wonder would rather be if Plato had seen an astronomical incompatibility which escaped the notice both of Aristotle and of many subsequent writers who wrote at a time when astronomical theories had been developed and compared with greater fulness. Even Ideler, a good astronomer as well as a good scholar, though he must surely have known that Plato asserted the rotation of the sidereal sphere (for no man can read the 'Timæus' without knowing it), ascribed to him also the other doctrine inconsistent with it, not noticing such inconsistency until M. Boeckh pointed it out.

It appears to me, therefore, that M. Boeckh has not satisfactorily made good his point--"Plato cannot have believed in the diurnal rotation of the earth, because he unquestionably believed in the rotation of the sidereal sphere as causing the succession of night and day." For, though the two doctrines really are incompatible, yet the critics antecedent to M. Boeckh took no notice of such incompatibility. We cannot presume that Plato saw what Aristotle and other authors, even many writing under a more highly developed astronomy, did not see. We ought rather, I think, to presume the contrary, unless Plato's words distinctly attest that he did see farther than his successors.

Now let us examine what Plato's words do attest:--[Greek: gê=n de\ tropho\n me\n ê(mete/ran, ei(llome/nên] (al. [Greek: ei(lome/nên, i)llome/nên]) [Greek: de\ peri\ to\n dia\ panto\s po/lon tetame/non phu/laka kai\ dêmiourgo\n nukto/s te kai\ ê(me/ras e)mêchanê/sato, prô/tên kai\ presbuta/tên theô=n, o(/soi e)nto\s ou)ra/nou gego/nasi.]

I explain these words as follows:--

In the passage immediately preceding, Plato had described the uniform and unchanging rotation of the outer sidereal sphere, or Circle of The Same, and the erratic movements of the sun, moon, and planets, in the interior Circles of the Diverse. He now explains the situation and functions of the earth. Being the first and most venerable of the intra-kosmic deities, the earth has the most important place in the interior of the kosmos--the centre. It is packed, fastened, or rolled, close round the axis which traverses the entire kosmos; and its function is to watch over and bring about the succession of night and day. Plato conceives the kosmic axis itself as a solid cylinder revolving or turning round, and causing thereby the revolution of the circumference or the sidereal sphere. The outer circumference of the kosmos not only revolves round its axis, but obeys a rotatory impulse emanating from its axis, like the spinning of a teetotum or the turning of a spindle. Plato in the Republic illustrates the cosmical axis by comparison with a spindle turned by Necessity, and describes it as causing by its own rotation the rotation of all the heavenly bodies (Republ. x. p. 616, c. 617 A). [Greek: e)k de\ tô=n a)/krôn tetame/non A)na/gkês a)/trakton, di' ou(= pa/sas e)pistre/phesthai ta\s peri/phoras . . . , kuklei=sthai de\ dê\ strepho/menon to\n a)/trakton o(/lon me\n tê\n au)tê\n phoran . . . . stre/phesthai de\ au)to\n e)n toi=s A)na/gkês go/nasin.]

----[Greek: to\n de\ a)/xona mi/an theo/têta sunagôgo\n me\n tô=n ke/ntrôn tou= panto\s sunektikê\n de\ tou= o(/lou ko/smou, kinêtikê\n de\ tô=n thei/ôn periphorô=n, peri\ ê(\n ê( chorei/a** tô=n o(/lôn, peri\ ê(\n ai( a)nakuklê/seis, a)ne/chousan to\n o(/lon ou)rano\n,** ê(\n kai\ A)/tlanta dia\ tou=to proseirê/kasin, ô(s a)/trepton kai\ a)/truton e)ne/rgeian e)/chousan. kai\ me/ntoi kai\ to\ tetame/non** e)ndei/knutai** titê/nion ei)=nai tê\n mi/an tau/tên du/namin, tê\n phrourêtikê\n tê=s a)nakuklê/seôs tô=n o(/lôn.]

Here Proklus recognises the efficacy of the axis in producing and maintaining the revolution of the Kosmos, but he does not remark that it initiates this movement by revolving itself. The [Greek: Theotê\s], which Proklus ascribes to the axis, is invested in the earth packed round it, by the Platonic Timæus.]

Now the function which Plato ascribes to the earth in the passage of the Timæus before us is very analogous to that which in the Republic he ascribes to Necessity--the active guardianship of the axis of the kosmos and the maintenance of its regular rotation. With a view to the exercise of this function, the earth is planted in the centre of the axis, the very root of the kosmic soul (Plato, Timæus, p. 34 B). It is even "packed close round the axis," in order to make sure that the axis shall not be displaced from its proper situation and direction. The earth is thus not merely active and influential, but is really the chief regulator of the march of the kosmos, being the immediate neighbour and auxiliary of the kosmic soul. Such a function is worthy of "the first and eldest of intra-kosmic deities," as Plato calls the earth. With perfect propriety he may say that the earth, in the exercise of such a function, "is guardian and artificer of day and night." This is noway inconsistent with that which he says in another passage, that the revolutions of the outer sidereal sphere determine day and night. For these revolutions of the outer sidereal sphere depend upon the revolutions of the axis, which latter is kept in uniform position and movement by the earth grasping it round its centre and revolving with it. The earth does not determine days and nights by means of its own rotations, but by its continued influence upon the rotations of the kosmic axis, and (through this latter) upon those of the outer sidereal sphere.

It is important to attend to the circumstance last mentioned, and to understand in what sense Plato admitted a rotatory movement of the earth. In my judgment, the conception respecting the earth and its functions, as developed in the Platonic Timæus, has not been considered with all its points taken together. One point among several, and that too the least important point, has been discussed as if it were the whole, because it falls in with the discussions of subsequent astronomy. Thus Plato admits the rotation of the earth, but he does not admit it as producing any effects, or as the primary function of the earth: it is only an indirect consequence of the position which the earth occupies in the discharge of its primary function--of keeping the cosmical axis steady, and maintaining the uniformity of its rotations. If the cosmical axis is to revolve, the earth, being closely packed and fastened round it, must revolve along with it. If the earth stood still, and resisted all rotation of its own, it would at the same time arrest the rotations of the cosmical axis, and of course those of the entire kosmos besides.

The above is the interpretation which I propose of the passage in the Platonic Timæus, and which I shall show to coincide with Aristotle's comment upon it. Messrs. Boeckh and Martin interpret differently. They do not advert to the sense in which Plato conceives the axis of the kosmos--not as an imaginary line, but as a solid revolving cylinder; and moreover they understand the function assigned by the Platonic Timæus to the earth in a way which I cannot admit. They suppose that the function assigned to the earth is not to keep up and regularize, but to withstand and countervail, the rotation of the kosmos. M. Boeckh comments upon Gruppe, who had said (after Ideler) that when the earth is called [Greek: phu/laka kai\ dêmiourgo\n nukto\s kai\ ê(me/ras], Plato must have meant to designate some active function ascribed to it, and not any function merely passive or negative. I agree with Gruppe in this remark, and I have endeavoured to point out what this active function of the earth is, in the Platonic theory. But M. Boeckh (Untersuchungen, &c., p. 69-70) controverts Gruppe's remark, observing, first, that it is enough if the earth is in any way necessary to the production of the given effect; secondly, that if active force be required, the earth (in the Platonic theory) does exercise such, by its purely passive resistance, which is in itself an energetic putting forth of power.

M. Boeckh's words are:--"Es kommt nur darauf an, dass er ein Werk, eine Wirkung, hervorbringt oder zu einer Wirkung beiträgt, die ohne ihn nicht wäre: dann ist er durch seine Wirksamkeit ein Werkmeister der Sache, sey es auch ohne active Thätigkeit, durch bloss passiven Widerstand, der auch eine mächtige Kraft-äusserung ist. Die Erde ist Werkmeisterin der Nacht und des Tages, wie Martin (b. ii. p. 88) sehr treffend sagt 'par son énergique existence, c'est à dire, par son immobilité même:' denn sie setzt der täglichen Bewegung des Himmels beständig eine gleiche Kraft in entgegengesetzter Richtung entgegen. So muss nach dem Zusammenhange ausgelegt werden: so meint es Platon klar und ohne Verhüllungen: denn wenige Zeilen vorher hat er gesagt, Nacht und Tag, das heisst ein Sterntag oder Zeittag, sei ein Umlauf des Kreises des Selbigen--das ist, eine tägliche Umkreisung des Himmels von Osten nach Westen, wodurch also die Erde in Stillstand versetzt ist: und diese tägliche Bewegung des Himmels hat er im vorhergehenden immer und immer gelehrt." . . . . "Indem Platon die Erde nennt [Greek: ei(lome/nên], nicht [Greek: peri\ to\n e(autê=s po/lon], sondern [Greek: peri\ to\n dia\ panto\s po/lon tetame/non], setzt er also die tägliche Bewegung des Himmels voraus" (p. 70-71).

I not only admit but put it in the front of my own case, that Plato in the Timæus assumes the diurnal movement of the celestial sphere; but I contend that he also assumes the diurnal rotation of the earth. M. Boeckh founds his contrary interpretation upon the unquestionable truth that these two assumptions are inconsistent; and upon the inference that because the two cannot stand together in fact, therefore they cannot have stood together in the mind of Plato. In that inference I have already stated that I cannot acquiesce.

But while M. Boeckh takes so much pains to vindicate Plato from one contradiction, he unconsciously involves Plato in another contradiction, for which, in my judgment, there is no foundation whatever. M. Boeckh affirms that the function of the earth (in the Platonic Timæus) is to put forth a great force of passive resistance--"to oppose constantly, against the diurnal movement of the heavens, an equal force in an opposite direction." Is it not plain, upon this supposition, that the kosmos would come to a standstill, and that its rotation would cease altogether? As the earth is packed close or fastened round the cosmical axis, so, if the axis endeavours to revolve with a given force, and the earth resists with equal force, the effect will be that the two forces will destroy one another, and that neither the earth nor the axis will move at all. There would be the same nullifying antagonism as if,--reverting to the analogous case of the spindle and the verticilli (already alluded to) in the tenth book of the Republic,--as if, while Ananké turned the spindle with a given force in one direction, Klotho (instead of lending assistance) were to apply her hand to the outermost verticillus with equal force of resistance in the opposite direction (see Reipubl. x. p. 617 D). It is plain that the spindle would never turn at all.

Here, then, is a grave contradiction attaching to the view of Boeckh and Martin as to the function of the earth. They have not, in my judgment, sufficiently investigated the manner in which Plato represents to himself the cosmical axis: nor have they fully appreciated what is affirmed or implied in the debated word [Greek: ei(lo/menon--ei(lou/menon--i)llo/menon]. That word has been explained partly by Ruhnken in his notes on Timæi Lexicon, but still more by Buttmann in his Lexilogus, so accurately and copiously as to leave nothing further wanting. I accept fully the explanation given by Buttmann, and have followed it throughout this article. After going over many other examples, Buttmann comes to consider this passage of the Platonic Timæus; and he explains the word [Greek: ei(lome/nên] or [Greek: i)llo/menên] as meaning--"sich drängen oder gedrängt werden um die Axe: d. h. von allen Seiten her an die Axe. Auch lasse man sich das Praesens nicht irren: die Kräfte, welche den Weltbau machen und zusammen halten, sind als fortdauernd thätig gedacht. Die Erde drängt sich (ununterbrochen) an den Pol, macht, bildet eine Kugel um ihn. Welcher Gebrauch völlig entspricht dem wonach dasselbe Verbum ein einwickeln, einhüllen, bedeutet. Auch hier mengt sich in der Vorstellung einiges hinzu, was auf ein biegen winden, und mitunter auf ein drehen führt: was aber überall nur ein durch die Sache selbst hinzutretender Begriff ist," p. 151. And again, p. 154, he gives the result--that the word has only "die Bedeutung drängen, befestigen, nebst den davon ausgehenden--die von drehen, winden, aber ihm gänzlich fremd sind, und nur aus der Natur der Gegenstände in einigen Fällen als Nebengedanken hinzutreten."

In these last words Buttmann has exactly distinguished the true, constant, and essential meaning of the word, from the casual accessories which become conjoined with it by the special circumstances of some peculiar cases. The constant and true meaning of the word is, being packed or fastened close round, squeezing or grasping around. The idea of rotating or revolving is quite foreign to this meaning, but may nevertheless become conjoined with it, in certain particular cases, by accidental circumstances.

Let us illustrate this. When I say that a body A is [Greek: ei(lo/menon] or [Greek: i)llo/menon] (packed or fastened close round, squeezing or grasping around), another body B, I affirm nothing about revolution or rotation. This is an idea foreign to the proposition per se, yet capable of being annexed or implicated with it under some accidental circumstances. Whether in any particular case it be so implicated or not depends on the question "What is the nature of the body B, round which I affirm A to be fastened?" 1. It may be an oak tree or a pillar, firmly planted and stationary. 2. It may be some other body, moving, but moving in a rectilinear direction. 3. Lastly, it may be a body rotating or intended to rotate, like a spindle, a spit, or the rolling cylinder of a machine. In the first supposition, all motion is excluded: in the second, rectilinear motion is implied, but rotatory motion is excluded: in the third, rotatory motion is implied as a certain adjunct. The body which is fastened round another, must share the motion or the rest of that other. If the body B is a revolving cylinder, and if I affirm that A is packed or fastened close round it, I introduce the idea of rotation; though only as an accessory and implied fact, in addition to that which the proposition affirms. The body A, being fastened round the cylinder B, must either revolve along with it and round it, or it must arrest the rotation of B. If the one revolves, so must the other; both must either revolve together, or stand still together. This is a new fact, distinct from what is affirmed in the proposition, yet implied in it or capable of being inferred from it through induction and experience.

Here we see exactly the position of Plato in regard to the rotation of the earth. He does not affirm it in express terms, but he affirms what implies it. For when he says that the earth is packed, or fastened close round the cosmical axis, he conveys to us by implication the knowledge of another and distinct fact--that the earth and the cosmical axis must either revolve together or remain stationary together--that the earth must either revolve along with the axis or arrest the revolutions of the axis. It is manifest that Plato does not mean the revolutions of the axis of the kosmos to be arrested: they are absolutely essential to the scheme of the Timæus--they are the grand motive-agency of the kosmos. He must, therefore, mean to imply that the earth revolves along with and around the cosmical axis. And thus the word [Greek: ei(lo/menon] or [Greek: i)llo/menon], according to Buttmann's doctrine, becomes accidentally conjoined, through the specialities of this case, with an accessory idea of rotation or revolution; though that idea is foreign to its constant and natural meaning.

Now if we turn to Aristotle, we shall find that he understood the word [Greek: ei(lo/menon] or [Greek: i)llo/menon], and the proposition of Plato, exactly in this sense. Here I am compelled to depart from Buttmann, who affirms (p. 152), with an expression of astonishment, that Aristotle misunderstood the proposition of Plato, and interpreted [Greek: ei(lo/menon] or [Greek: i)llo/menon] as if it meant directly as well as incontestably, rotating or revolving. Proklus, in his Commentary on the Timæus, had before raised the same controversy with Aristotle--[Greek: i)llome/nên de\, tê\n sphiggome/nên dêloi= kai\ sunechome/nên ou) ga\r ô(s A)ristote/lês oi)/etai, tê\n kinoume/nên] (Procl. p. 681). Let us, therefore, examine the passages of Aristotle out of which this difficulty arises.

The passages are two, both of them in the second book De Coelo; one in cap. 13, the other in cap. 14 (p. 293 b. 30, 296 a. 25).

1. The first stands--[Greek: e)/nioi de\ kai\ keime/nên (tê\n gê=n) e)pi\ tou= ke/ntrou phasi\n au)tê\n i)/llesthai peri\ to\n dia\ panto\s tetame/non po/lon, ô(/sper e)n tô=| Timai/ô|** ge/graptai.** Such is the reading of Bekker in the Berlin edition: but he gives various readings of two different MSS.--the one having [Greek: i)/llesthai kai\ kinei=sthai]--the other ei(lei=sthai** kai\ kinei=sthai].

2. The second stands, beginning chap. 14--[Greek: ê(mei=s de\ le/gômen prô=ton po/teron] (the earth) [Greek: e)/chei ki/nêsin ê)\ me/nei; katha/per ga\r ei)/pomen, oi( me\n au)tê\n e(\n tô=n a)/strôn poiou=sin, oi( d' e)pi\** tou= me/sou the/ntes i)/llesthai kai\ kinei=shai/ phasi peri\ to\n po/lon me/son.]

Now, in the first of these two passages, where Aristotle simply brings the doctrine to view without any comment, he expressly refers to the Timæus, and therefore quotes the expression of that dialogue without any enlargement. He undoubtedly understands the affirmation of Plato--that the earth was fastened round the cosmical axis--as implying that it rotated along with the rotations of that axis. Aristotle thus construes [Greek: i)/llesthai], in that particular proposition of the Timæus, as implying rotation. But he plainly did not construe [Greek: i)/llesthai] as naturally and constantly either denoting or implying rotation. This is proved by his language in the second passage, where he reproduces the very same doctrine with a view to discuss and confute it, and without special reference to the Platonic Timæus. Here we find that he is not satisfied to express the doctrine by the single word [Greek: i)/llesthai]. He subjoins another verb--[Greek: i)/llesthai kai\ kinei=sthai]: thus bringing into explicit enunciation the fact of rotatory movement, which, while [Greek: i)/llesthai] stood alone, was only known by implication and inference from the circumstances of the particular case. If he had supposed [Greek: i)/llesthai] by itself to signify revolving the addition of [Greek: kinei=sthai] would have been useless, unmeaning, and even impertinent. Aristotle, as Boeckh remarks, is not given to multiply words unnecessarily.

It thus appears, when we examine the passages of Aristotle, that he understood [Greek: i)/llesthai] quite in conformity with Buttmann's explanation. Rotatory movement forms no part of the meaning of the word; yet it may accidentally, in a particular case, be implied as an adjunct of the meaning, by virtue of the special circumstances of that case. Aristotle describes the doctrine as held by some persons. He doubtless has in view various Platonists of his time, who adopted and defended what had been originally advanced by Plato in the Timæus.

M. Boeckh, in a discussion of some length (Untersuch. p. 76-84), maintains the opinion that the reading in the first passage of Aristotle is incorrect; that the two words [Greek: i)/llesthai kai\ kinei=sthai] ought to stand in the first as they do in the second,--as he thinks that they stood in the copy of Simplikius: that Aristotle only made reference to Plato with a view to the peculiar word [Greek: i)/llesthai], and not to the general doctrine of the rotation of the earth: that he comments upon this doctrine as held by others, but not by Plato--who (according to Boeckh) was known by everyone not to hold it. M. Boeckh gives this only as a conjecture, and I cannot regard his arguments in support of it as convincing. But even if he had convinced me that [Greek: i)/llesthai kai\ kinei=sthai] were the true reading in the first passage, as well as in the second, I should merely say that Aristotle had not thought himself precluded by the reference to the Timæus from bringing out into explicit enunciation what the Platonists whom he had in view knew to be implied and intended by the passage. This indeed is a loose mode of citation, which I shall not ascribe to Aristotle without good evidence. In the present case such evidence appears to me wanting.

M. Martin attributes to Aristotle something more than improper citation. He says (Êtudes sur le Timée, vol. ii. p. 87), "Si Aristote citait l'opinion de la rotation de la terre comme un titre de gloire pour Platon, je dirais--il est probable que la vérité l'y a forcé. Mais Aristote, qui admettait l'immobilité complète de la terre, attribue à Platon l'opinion contraire, pour se donner le plaisir de la réfuter avec dédain." A few lines before, M. Martin had said that the arguments whereby Aristotle combated this opinion ascribed to Plato were "very feeble." I am at a loss to imagine in which of Aristotle's phrases M. Martin finds any trace of disdain or contempt, either for the doctrine or for those who held it. For my part, I find none. The arguments of Aristotle against the doctrine, whatever be their probative force, are delivered in that brief, calm, dry manner which is usual with him, without a word of sentiment or rhetoric, or anything [Greek: e)/xô tou= pra/gmatos]. Indeed, among all philosophers who have written much, I know none who is less open to the reproach of mingling personal sentiment with argumentative debate than Aristotle. Plato indulges frequently in irony, or sneering, or rhetorical invective; Aristotle very rarely. Moreover, even apart from the question of contempt, the part which M. Martin here assumes Aristotle to be playing, is among the strangest anomalies in the history of philosophy. Aristotle holds, and is anxious to demonstrate, the doctrine of the earth's immobility; he knows (so we are required to believe) that Plato not only holds the same doctrine, but has expressly affirmed it in the Timæus: he might have produced Plato as an authority in his favour, and the passage of the Timæus as an express declaration; yet he prefers to pervert, knowingly and deliberately, the meaning of this passage, and to cite Plato as a hostile instead of a friendly authority--simply "to give himself the pleasure of contemptuously refuting Plato's opinion!" But this is not all. M. Martin tells us that the arguments which Aristotle produces against the doctrine are, after all, very feeble. But he farther tells us that there was one argument which might have been produced, and which, if Aristotle had produced it, would have convicted Plato of "an enormous contradiction" (p. 88) in affirming that the earth revolved round the cosmical axis. Aristotle might have said to Plato--"You have affirmed, and you assume perpetually throughout the Timæus, the diurnal revolution of the outer sidereal sphere; you now assert the diurnal revolution of the earth at the centre. Here is an enormous contradiction; the two cannot stand together."--Yet Aristotle, having this triumphant argument in his hands, says not a word about it, but contents himself with various other arguments which M. Martin pronounces to be very feeble.

Perhaps M. Martin might say--"The contradiction exists; but Aristotle was not sharpsighted enough to perceive it; otherwise he would have advanced it." I am quite of this opinion. If Aristotle had perceived the contradiction, he would have brought it forward as the strongest point in his controversy. His silence is to me a proof that he did not perceive it. But this is a part of my case against M. Martin. I believe that Plato admitted both the two contradictory doctrines without perceiving the contradiction; and it is a strong presumption in favour of this view that Aristotle equally failed to perceive it--though in a case where, according to M. Martin, he did not scruple to resort to dishonest artifice.