philosophy of nature-第5部分
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§ 205。
Matter； as having gravity； is only： （1） matter existing in itself or general。 But this concept must： （2）
specify itself； thus it is elementary matter； and the object of elementary physics。 （3） Particular
matter taken together is individualised matter； and the object of physics as the actual world of the
body。
A。
Mechanics
§ 206。
Matter； as simply general； has at first only a quantitative difference； and particularises itself into
different quanta； … masses； which； in the superficial determination of a whole or one； are bodies。
§ 207。
The body is： （1） as heavy matter the solid identity of space and time； but （2） as the first negation it
has in itself their ideality； which differentiates them from each other and from the body。 The body is
essentially in space and time； of which it constitutes its indifferent content in contrast to this form。
§ 208。
（3） As space； in which time is suspended； the body is enduring； and （4） as time； in which the
indifferent subsistence of space is suspended； the body is transitory。 In general； it is a wholly
contingent unit。 （5） But as the unity which binds together the two moments in their opposition； the
body essentially has motion； and the appearance of gravity。
Because the forces have been seen as only implanted onto matter； motion in particular is
considered to be a determination external to the body； even by that physics which is presumably
scientific。 It has thus become a leading axiom of mechanics that the body is set in motion or placed
into a condition only by an external cause。 On the one hand it is the understanding which holds
motion and rest apart as nonconceptual determinations； and therefore does not grasp their
transition into each other； but on the other hand only the selfless bodies of the earth；。 which are the
object of ordinary mechanics； appear in this representation。 The determinations； which occur in the
appearance of such bodies and are valid； are set as the foundation； and the nature of the
independent bodies is subsumed under this category。 In fact； however； the latter are truly more
general and the former is that which is subsumed absolutely； and in absolute mechanics the
concept presents itself in its truth and singularity。
§ 209。
In motion； time posits itself spatially as place； but this indifferent spatiality becomes just as
immediately temporal： the place becomes another （cf § 202）。 This difference of time and space is；
as the difference of their absolute unity and their indifferent content； a difference of bodies； which
hold themselves apart from each other yet equally seek their unity through gravity； — general
gravitation。
§ 210。
Gravitation is the true and determinate concept of material corporeality； which is thereby just as
essentially divided into particular bodies； and which has its manifested existence； the moment of
external individuality； in movement； which is thus determined immediately as a relation of several
bodies。
General gravitation must be recognised for itself as a profound thought； which constitutes an
absolute basis for mechanics if it is conceived initially in the sphere of reflection； though it is so
bound up with it through the quantitative determinations that it has attracted attention and credit；
and its verification has been based solely on the experience analysed from the solar system down
to the phenomenon of the capillary tubes。 Certainly gravitation directly contradicts the law of
inertia； for； by virtue of the former； matter strives to get out of itself to another。 In the concept of
gravity； as has been shown； there are included the two moments of being for itself and of that
continuity that suspends being for itself These moments of the concept now experience the fate； as
particular forces corresponding to the power of attraction and repulsion； of being conceived more
precisely as the centripetal and the centrifugal forces； which are supposed； like gravity； to act on
bodies； and independently of each other and contingently； to meet together in a third entity； the
body。 In this way whatever profundity was contained in the thought of general gravitation is
destroyed again； and the concept and reason will be unable to penetrate into the theory of
absolute motion； as long as the vaunted discoveries of forces prevail there。
if one closely considers the quantitative determinations which have been identified in the laws of
the centripetal and the centrifugal forces； one very quickly discovers the confusion which emerges
from their separation。 This confusion becomes even greater if the separation is mentioned in
relation to gravitation； gravitation； also called attraction； then seems to be the same as centripetal
force； the law of this individual force is taken as the law of the whole of gravitation； and the
centrifugal force； which at another time is valued as thoroughly essential； is viewed as something
quite superfluous。…In the above proposition； which contains the immediate idea of gravitation；
gravity itself namely； as the concept； which shows itself in the particularity of the body through the
external reality of motion； the rational identity and inseparability of these two moments are
contained。…The relativity of motion also shows itself in this proposition； which only makes sense in
a system of several bodies standing in relation to each other in accordance with a varied
determination； so that a different determination will immediately result。
§ 211。
The particular bodies in which gravity is realised have； as the determinations of their different
natures； the moments of their concept。 One body； therefore； is the general centre of being in itself。
Opposing this extreme stands individuality； existing outside of itself and without a centre。 But the
particular bodies are others； which stand in the determination of being outside of themselves and
are at the same time； as being in themselves； also centres for themselves； and are related to the
first body as to their essential unity。
§ 212。
（1） The motion of bodies of relative centrality； in relation to bodies of abstract； general centrality；
is absolutely free motion； and the conclusion of this system is that the general central body is
brought together through relative centrality with dependent corporeality。
As is well…known； the laws of absolutely free motion were discovered by Kepler； a discovery of
immortal fame。 Kepler proved them； too； in the sense that he found the general expression for the
empirical data （cf § 145）。 Since then it has become a commonplace that Newton first found the
proofs of these laws。 Not often has fame been more unjustly transferred from the first discoverer
to another。 Here I only want to point out what has basically already been admitted by
mathematicians； namely： （1） that the Newtonian formulas can be derived from Keplerian laws； （2）
that the Newtonian proof of the proposition that a body governed by the law of gravitation moves
in an ellipse around the central body proceeds in general in a conic section； whereas the main point
that was to be proven consists precisely in this； that the course of such a body is neither a circle
nor any other conic section； but solely the ellipse。 The conditions which make the course of the
body into a specific conic section are referred back to an empirical condition； namely； a particular
situation of the body at a specific point in time； and to the contingent strength of an impulse which
it is supposed to have received at the beginning。 （3） Newton's 'law〃 of the force of gravity has
likewise only been demonstrated inductively from experience。
On closer inspection it appears that what Kepler； in a simple and sublime manner； articulated in
the form of laws of celestial motion； Newton converted into the nonconceptual； reflective form of
the force of gravity。 The whole manner of this 〃proof〃 presents in general a confused tissue of lines
of merely geometrical construction to which a physical meaning of independent forces is given； of
the empty concepts of the understanding of a force of acceleration； of particles of time； at whose
beginning those forces always play a renewed role； and of a force of inertia； which presumably
continues its previous effect； and so on。 A rational proof of the quantitative determinations of free
motion can only rest on the determinations of the concepts of space and time； the moments whose
relation is motion。
§ 213。
（2） The absolute relation of those dependent bodies； which are merely the extreme of the being
outside of itself of gravity and therefore lack their own centrality to their relative central bodies； is
the residual element of their gravity in them； which because of physical being outside of themselves
is mere striving and； therefore； a pressure directed tow
