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not such a one as has the principle of rest or motion external to itself. It is not right to say because a stone is inert, and the whole earth consists of stones, and the other heavenly bodies are of the same nature as the earth, therefore the heavenly bodies are inert. This conclusion makes the properties of the whole the same as those of the part. Impulse, Pressure, Resistance, Friction, Pulling, and the like, are valid only for other than celestial matter."

There can be no doubt that this is a very different doctrine from that of Newton.

I will only add to these specimens of Hegel's physics, a specimen of the logic by which he refutes the Newtonian argument which has just been adduced; namely, that the celestial bodies are matter, and that matter, as we see in terrestrial matter, is inert. He says (x),

"Doubtless both are matter, as a good thought and a bad thought are both thoughts; but the bad one is not therefore good, because it is a thought."

APPENDIX TO THE MEMOIR ON HEGEL'S CRITICISM OF NEWTON'S PRINCIPIA.

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HEGEL. Encyclopædia (2nd Ed. 1827), Part XI. p. 250.

C. Absolute Mechanics.

§ 269.

RAVITATION is the true and determinate conception of material Corporeity, which (Conception) is realized to the Idea (zur Idee). General Corporeity is separable essentially into particular Bodies, and connects itself with the Element of Individuality or subjectivity, as apparent (phenomenal) presence in the Motion, which by this means is immediately a system of several Bodies.

Universal gravitation must, as to itself, be recognised as a profound thought, although it was principally as apprehended in the sphere of Reflexion that it eminently attracted notice and confidence on account of the quantitative determinations therewith connected, and was supposed to find its confirmation in Experiments (Erfahrung) pursued from the Solar System down to the phenomena

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of Capillary Tubes.-But Gravitation contradicts immediately the Law of Inertia, for in virtue of it (Gravitation) matter tends out of itself to the other (matter).—In the Conception of Weight, there are, as has been shown, involved the two elements-Self-existence, and Continuity, which takes away self-existence. These elements of the Conception, however, experience a fate, as particular forces, corresponding to Attractive and Repulsive Force, and are thereby apprehended in nearer determination, as Centripetal and Centrifugal Force, which (Forces) like weight, act upon Bodies, independent of each other, and are supposed to come in contact accidentally in a third thing, Body. By this means, what there is of profound in the thought of universal weight is again reduced to nothing; and Conception and Reason cannot make their way into the doctrine of absolute motion, so long as the so highly-prized discoveries of Forces are dominant there. In the conclusion which contains the Idea of Weight, namely, [contains this Idea] as the Conception which, in the case of motion, enters into external Reality through the particularity of the Bodies, and at the same time into this [Reality] and into their Ideality and self-regarding Reflexion, (Reflexion-in-sich), the rational identity and inseparability of the elements is involved, which at other times are represented as independent. Motion itself, as such, has only its meaning and existence in a system of several bodies, and those, such as stand in relation to each other according to different determinations.

§ 270.

As to what concerns bodies in which the conception of gravity (weight) is realized free by itself, we say that they have for the determinations of their different nature the elements (momente) of their conception. One [conception of this kind] is the universal center of the abstract reference [of a body] to itself. Opposite to this [conception] stands the immediate, extrinsic, centerless Individuality, appearing as Corporeity similarly independent. Those [Bodies] however which are particular, which stand in the determination of extrinsic, and at the same time of intrinsic relation, are centers for themselves, and [also] have a reference to the first as to their essential unity.

The Planetary Bodies, as the immediately concrete, are in their existence the most complete. Men are accustomed to take the Sun as the most excellent, inasmuch as the understanding prefers the abstract to the concrete, and in like manner the fixed stars are esteemed higher than the Bodies

of the Solar System. Centerless Corporeity, as belonging to externality, naturally separates itself into the opposition of the lunar and the cometary Body. The laws of absolutely free motion, as is well known, were discovered by Kepler;—a discovery of immortal fame. Kepler has proved these laws in this sense, that for the empirical data he found their general expression. Since then, it has become a common way of (a) speaking to say that Newton first found out the proof of these Laws. It has rarely happened that fame has been more unjustly transferred from the first discoverer to another person. On this subject I make the following remarks.

1. That it is allowed by Mathematicians that the Newtonian Formulæ may be derived from the Keplerian Laws. (b) The completely immediate derivation is this: In the third A8 (c) Keplerian Law, is the constant quantity. This being put

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tion, his expression of the effect of gravity in the reciprocal ratio of the square of the distances is obvious.

(d) 2. That the Newtonian proof of the Proposition that a body subjected to the Law of Gravitation moves about the central body in an Ellipse, gives a Conic Section generally, while the main Proposition which ought to be proved is that the fall of such a Body is not a Circle or any other Conic Section, but an Ellipse only. Moreover, there are objections which may be made against this proof in itself (Princ. Math. 1. 1. Sect. II. Prop. 1); and although it is the foundation of the (e) Newtonian Theory, analysis has no longer any need of it. The conditions which in the sequel make the path of the Body to a determinate Conic Section, are referred to an empirical circumstance, namely, a particular position of the Body at a determined moment of time, and the casual strength of an (f) impulsion which it is supposed to have received originally; so that the circumstance which makes the Curve be an Ellipse, which alone ought to be the thing proved, is extraneous to the Formula.

3. That the Newtonian Law of the so-called Force of Gravitation is in like manner only proved from experience by Induction.

(g) The sum of the difference is this, that what Kepler expressed in a simple and sublime manner in the Form of Laws

of the Celestial Motions, Newton has metamorphosed into the Reflection-Form of the Force of Gravitation. If the Newtonian Form has not only its convenience but its necessity in reference to the analytical method, this is only a difference (h) of the mathematical formulæ; Analysis has long been able to derive the Newtonian expression, and the Propositions therewith connected, out of the Form of the Keplerian Laws; (on this subject I refer to the elegant exposition in Francœur's (i) Traité Elém. de Mécanique, Liv. 11. Ch. xi. n. 4.)—The old method of so-called proof is conspicuous as offering to us a tangled web, formed of the Lines of the mere geometrical construction, to which a physical meaning of independent Forces is given; and of empty Reflexion-determinations of the already mentioned Accelerating Force and Vis Inertia, and especially of the relation of the so-called gravitation itself to the centripetal force and centrifugal force, and so on.

The remarks which are here made would undoubtedly have need of a further explication to show how well founded they are: in a Compendium, propositions of this kind which do not agree with that which is assumed, can only have the shape of assertions. Indeed, since they contradict such high authori ties, they must appear as something worse, as presumptuous assertions. I will not, on this subject, support myself by saying, by the bye, that an interest in these subjects has occupied me for 25 years; but it is more precisely to the purpose to remark, that the distinctions and determinations which Mathematical Analysis introduces, and the course which it must take according to its method, is altogether different from that which a physical reality must have. The Presuppositions, the Course, and the Results, which the Analysis necessarily has and gives, remain quite extraneous to the considerations which determine the physical value and the signification of those determinations and of that course. To this it is that attention should be directed. We have to do with a consciousness relative to the deluging of physical Mechanics with an inconceivable (unsäglichen) Metaphysic, which-contrary to experience and conception-has those mathematical determinations alone for its source.

It is recognized that what Newton-besides the foundation of the analytical treatment, the development of which, by the bye, has of itself rendered superfluous, or indeed rejected much which belonged to Newton's essential Principles and glory-has added to the Keplerian Laws is the Principle of

Perturbations,-a Principle whose importance we may here accept thus far (hier in sofern anzufuhren ist); namely, so (k) far as it rests upon the Proposition that the so-called attraction is an operation of all the individual parts of bodies, as (7) being material. It lies in this, that matter in general assigns a center for itself (sich das centrum setzt), and the figure of the body is an element in the determination of its place; that collective bodies of the system recognize a reference to their Sun (sich ihre Sonne setzen), but also the individual bodies themselves, according to the relative position with regard to each other into which they come by their general motion, form a momentary relation of their gravity (schwere) towards each other, and are related to each other not only in abstract spatial relations, but at the same time assign to themselves a joint center, which however is again resolved [into the general center] in the universal system.

(m)

As to what concerns the features of the path, to show how the fundamental determinations of Free Motion are connected with the Conception, cannot here be undertaken in a satisfactory and detailed manner, and must therefore be left to its fate. The proof from reason of the quantitative determinations of free motion can only rest upon the determinations of Conceptions of space and time, the elements whose relation (intrinsic not extrinsic) motion is.

That, in the first place, the motion in general is a motion returning into itself, is founded on the determination of particularity and individuality of the bodies in general (§ 269), so that partly they have a center in themselves, and partly at the same time their center in another. These are the determinations of Conceptions which form the basis of the false representatives (n) of Centripetal Force and Centrifugal Force, as if each of these were self-existing, extraneous to the other, and independent of it; and as if they only came in contact in their operations and consequently externally. They are, as has already been mentioned, the Lines which must be drawn for the mathematical determinations, transformed into physical realities.

Further, this motion is uniformly accelerated, (and—as returning into itself—in turn uniformly retarded). In motion as free, Time and Space enter as different things which are to make themselves effective in the determination of the motion (a) (§ 266, note). In the so-called Explanation of the uniformly accelerated and retarded motion, by means of the alternate

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