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

PHYSICS 477
mutation, it stands above the strife of the elements:
these belong to the terrestrial, it to the celestial, world :
of it are formed the heavenly spheres and stars ; it is
the god-like in the realm of matter. 1
The four elements are different in all respects. If
circular movement is peculiar to the ffither, their movement
is rectilineal. But, as we have remarked, rectilineal
motionfollows two opposite directions, upand down,
toward the circumference and toward the centre.
which tends naturally downwards is heavy ;
That
that which
rises is light. Accordingly the elements exhibit the
opposites of heavy and light. 2
This opposition cannot,
he holds, be reduced to quantitative differences of magnitude,
of mathematical figure, or density ; it is original
and qualitative. The peculiarities of the elementary
materials we cannot explain either, with Plato and Democritus,
by the mathematical qualities of atoms, or, with
the elder physicists, by the rarefaction and condensation
locality can it be said to move i!a.ij is denied of them in the
merely Suvi/iet and not ivepyelq, same sense as it is denied of the
inasmuch as it is not yet in the immaterial Nous, or that it can
place to which it is moving] be attributed to the latter in the
toutou S' [i.b. toS irSBev iroi /civet- same sense as to the former.
aSai] S\riv aiiSh KoiXiet virapx^tv.
' It is called Beibs, Meteor, i.
Be Cmlo, i. 9, 278, a, 10 sqq. 3, 339, b, 25 ;
also, similarly, Be
Aristotle expressly says : 6 oipavbs Cmlo, i. 3, 270, b, 11, 20 : f) vptirri
as a universal conception is ovata ray crati&Twv, rb irpdrov
different from 85e 6 ovpa.v6s ; the /ia, 'irepdy rihv irapa. yyv Kal irvp
former is elSos Kal popQii, the ku\ aipa Kal SSap. Ibid. ii. 1, 284,
latter rij SAp ^fuy^vov. Still a, 4 Later philosophers, such as
less can we 'infer from Metajrfi. Cicero's Epicurean (TV. Be. i. 13,
viii 4, that the 'celestial globes 33, cf. Krische, Ibrsch., 306
are incorporeal beings (like the sqq.) and the pseudo-Justin
sether, they are frequently called Cohort, c. 5, 36, identify on this
Beta, a-diiara, &c. : see Ind. Ar. ground God and the jether.
742, a, 43-60) we cannot, there- 2
See p. 473 sq.
;
fore, suppose for a moment that
478 ARISTOTLE
of one and the same primitive material. We have
already proved this point with regard to the first
hypothesis. 1 But those who deduce the differences of
matter from a condensation and rarefaction of some one
original element are, besides other arguments, met by
the objection that they do not explain the distinction
between light and heavy substance. They confine
the difference between the elements to a mere relation
of magnitudes, and accordingly represent it as something
merely relative. 2 To Aristotle's mind, the opposition
of rectilineal movements and natural localities
once demands a
qualitative difference between the elements.
Eectilineal motion being just as primitive as
circular motion, there must be certain bodies which are
especially designed for it. 3 Again, since it includes
two tendencies, upward and downward, we must in the
first place assume two bodies, of which one naturally
sinks, the other rises, the one tending to the centre, the
other to the circumference of the world.
at
In the second
place, we must imagine an intermediate element, or
rather a pair of elements, the one approximating to
the former, and the other to the latter. Of these four
bodies, the first two are earth and fire, the other two
water and air. Earth is absolutely heavy and entirely
devoid of lightness ;
fire is absolutely light and entirely
devoid of heaviness. The one moves straight to the
centre, and therefore sinks below all other bodies ; the
other moves straight to the circumference, and therefore
1
See p. 443 sqq. 20 ; Metaph. i. 8, 988, b, 29 sqq.
2
Aristotle discusses this view s
See p. 473.
De Ceelo, iii. 5, of. iv. 5, 312, b,