ARISTOTLE AND THE EARLIER PERIPATETICS vol.I by Eduard Zeller, B.F.C.Costelloe 1897

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PHYSICS 445
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triangles are left over, 1
and that it is as easy to think of
a superimposition of surfaces as of the composition
assumed by Plato. 2 Furthermore, the theory of unchangeable
type forms of the elements contradicts the
fact that the shape of simple bodies—water and earth,
for instance—is determined by the surrounding space. 3
In the last place, how are we to comprehend the
qualities and movements of the elements by these
hypotheses of Plato?
Democritus supposed that fire
was formed of globes, on account of its mobility and
disruptive force ;
Plato thought it was made of pyramids,
but that the earth was made of cubes, on account of its
comparative immobility. Yet both of these elements
are hard to move in their own locality, and easy to move
in a strange one, since they strive to escape from the
latter and not from the former. 4 Aristotle is therefore
forced to regard Plato's theory of the elements as in
every respect mistaken. 5
The Atomic theory of Democritus and Leucippus is
treated by him with more respect
6
but he holds that
1
Ibid. 1. 20 ; cf. Plato, Tim. ball does not change that with
56 D sq. which it comes into contact into
2
De Ccelo, iii. 1, 299, b, 23. balls or pyramids. Fire sepa-
3
Ibid. c. 8, 306, b, 9. rates only dissimilars, whereas it
4
Ibid. 306, b, 29 sqq., where unites similars. Further, if heat
it is farther objected that balls be united to a particular shape,
and pyramids are easily moved so also must cold.
only in a circle, whereas tire has 5
Pkoclus at a later date dean
upward movement. Again, if fended it in a, separate treatise
it is its corners that give to against his attacks ; Simpl.,
tire its heat-producing power, all Sohol. in Ar. 515, a, 4.
elementary bodies must likewise ° Cf. the discussion in Gen. et
produce heat as well as every- Corr.i. 2,315, b, 30 sqq., the chief
thing that has mathematical sentences of which are cited in
shape, for they all have coiners. Zell. Ph. d. Gr. pt. i. 771, 4
; also,
Fire changes things which it on the Platonic theory, cf. De
seizes into fire ; a pyramid or a Ccelo, iii. 7, 306, a, 5 sqq.
ARISTOTLE
so is far from having proved that everything may
leduced from a primitive matter of absolutely homosous
quality.
In the first place, it is open to all the
ctions which beset the hypothesis of indivisible
ies. 1 Next, as in the case of Plato, it is clear that
materials could not adjust their shape to
the space
rhich they find themselves, if we attribute a distinct
lentary figure to them. 2 In the next place, we
ady 3 know. the reasons why Aristotle is not inclined
dmit an infinite variety of difference of shape among
atoms ;
and if the elementary atoms are to be dis-
;uished only by their size, one element could not be
sloped from another. 4 If all the atoms are homoeous,
one does not see how they are separate, and
t they do not join when brought into contact with
another. If they are composed of heterogeneous
;erials, we should have to seek the cause of phenomena
his circumstance, and not in the difference of shape,
then they would influence one another while in con-
See, besides p. 306, the state- collision. It is certainly hard to
;s quoted p. 430. n. 2, all of see how a cohesive body could be
h are more or less directly constituted of such atoms. The
d at the atomists. Here means which Democritus adopted
we must continually remind for securing this end by attributives
of the state of science ing corners and hooks to atoms,
Le time, and of the peculiar by which they may hang on to
a,cter of the theory which one another (Zbll. Ph. d. Gr.
otle attacked. When, for i. 796, 2, 798, 4), could not
mce, he shows that atoms but appear to Aristotle, as they
J not cohere in a solid body, he appeared (according to Cic.
t speaking of the atoms of Acad. ii. 38, 121) to his follower
3rn physics, which attract and Strato, fantastic and absurd.
[ one another, are held in a
See p. 445, n. 3, supra.
librium,&c.,inmanydifferent s
Seep. 331 sq.
s, but of the atoms of Democriwhich
act upon one another
4
De Ccelo, iii. 4, 303, a 24 sqq.
Cf. p. 306, n. 6.
mechanically by pressure or