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

;
;
PHYSICS 451
fact the transmutation of materials, the indivisibility
of these elementary substances would follow, 1 and this
he finds to be at direct variance with the nature of
corporeity. 2 As to the theory of Empedocles and the
Atomists, it is clear that, according to them, those substances
into which others seem to be transformed existed
previously in a state of interminglement with the latter,
and are merely extruded from them. Aristotle thinks
that this conception is, in the first place, at variance
with the testimony of our senses. 3
Experience shows
us a metamorphosis of materials in which the elementary
properties of substances alter. One substance
passes into another, or a third is formed of several.
When water freezes or ice melts, the phenomenon is not,
he says, occasioned by a mere alteration in the position
and order of the parts, nor has a mere separation or combination
of materials taken place, but, while the substance
remains the same, certain of its qualities have
changed. 4
Again, when water is made from air, a body
comesinto existence heavier than air, yet not, he thinks, as
a consequence of the separation and compression of certain
portions of the air. Conversely, when air is produced
1
Be Casio, iii. 7, 305, b, 28 that underlies all the elements
sqq., 306, a, 30. The meaning is alike (as was actually done by
that we may suppose the ele- Philolaus, cf. Zell. Ph. d. Gr.
ments formed of atoms of a defi- i. 376 sq.). By thus conceiving
nite shape—earth of cubical, fire of the atoms of the elements as
of quadrilateral, atoms—without divisible, however, we should inadopting
Plato's view of the con- volve ourselves in the difficulty
stitutionof these bodies, and that already mentioned, p. 444, n. 3.
the conversion of one element 2 See p. 430, n. 2, supra.
into another may be explained, * Gen. et Corr. i. 1, 314, b,
not as its resolution into its pri- 10 sqq. Be Casio, iii. 7, 305, b, 1.
mal surfaces and the combination Metaph. i. 8, 989, a, 22 sqq.
of these into a new form, but as
4
Gen. et Corr. i. 9, 327, a, 14
a transformation of the material sqq.
452 ARIST6TLE
by evaporation from water, the former occupies so large
a space in comparison with the latter that it even bursts
the vessel. How is this to be explained on the hypothesis
that it had previously existed in the water without
change or difference ? '
If a body grows or dwindles,
it is not merely thab new parts are added to it, but all
its parts increase or diminish in size—and this involves
a general change in the material. 2 When bones and
flesh are formed from food, they are not taken ready
made from what we eat, like bricks from a wall or water
from a cask, but the food passes into a new material. 3
Moreover, it is
into existence and perish :
clear that the elements themselves come
fire is kindled and goes out
water is precipitated from the air and passes into steam
again. How are we to conceive of such formation
and dissolution? There must be definite points at
which they begin and end, as in the case of all Becoming,
else we should be driven to suppose an infinite progression
in two directions.
Yet these terminal points
cannot consist of indivisible bodies—whether absolutely
indivisible (or atoms) as we have already seen, 4
or such
1
De Cailo, as above, 305, b, to explain steam as a kind of air
5 sqq. Aristotle's view of gravity which emanates from water ; nor
precludes the admission that the could atomists generally regard
greater weight of water as com- it as other than a complex of
pared with steam is due merely atqms emanating from water in
to its greater density. The atom- which they had previously been
ists of that time could not pos- imprisoned. As against such theosibly
explain the expansion of riesAristotle'sobjectionsarevalid.
fluids into steam as the
2
result of Gen. et Corr. i. 9, 327, a, 22.
increased repulsion in the atoms
3 Ibid. ii. 7, 334, a, 18, 26 ; cf.
at least the atoms of Democritus De Cailo, iii. 7, 305, b, 1. Cf. p.
are certainly incapable of internal 457 sq.
change. Empedocles and Anax- ' In the passage from DeCailo,
agoras,(with whom Aristotle, Hid. iii. 1, cited at pp. 306, n. 6, and
1. 16 sqq., first deals) were obliged 446, n. 4.