1 The Aristotelian criticisms which may have affected Epicurus are such as we find in de Caelo, 275 b 29 sqq. Aristotle there argues that, as Leukippos and Demokritos made the φύσις of the atoms one, they were bound to give them a single motion. That is just what Epicurus did, but Aristotle’s argument implies that Leukippos and Demokritos did not. Though he gave the atoms weight, Epicurus could not accept Aristotle’s view that some bodies are naturally light. The appearance of lightness is due to ἔκθλιψις, the squeezing out of the smaller atoms by the larger.
2 In dealing with Empedokles, Aristotle expressly makes this distinction. Cf. de Caelo, B, 13, especially 295 a 32 sqq., where he points out that Empedokles does not account for the weight of bodies on the earth (οὐ γὰρ H ye δίνη πλησιάζει πρὸς ἡμᾶς), nor for the weight of bodies before the vortex arose (πρὶν γενέσθαι τὴν δίνην).
3 Diog., Joc. ctt. (p. 390).
398 Early Greek Philosophy
may express that by saying that the larger are heavy
and the smaller light, and this will amply account for
everything Aristotle and Theophrastos say; for there
is no passage where the atoms outside the vortex are
distinctly said to be heavy or light.’
There is a striking confirmation of the view just given in the atomist cosmology quoted above.” We are told there that the separation of the larger and smaller atoms was due to the fact that they were “no longer able to revolve. in equilibrium owing to their number,” which implies that they had previously been in a state of “equilibrium” or “equipoise.” Now the word icoppomia has no necessary implication of weight in Greek. A ῥοπή is a mere leaning or inclination in a certain direction, which may be caused by weight or anything else. The state of ἰσορροπία is therefore that in which the tendency in one direction is exactly equal to the tendency in any other, and such a state is more naturally described as the absence of weight! than as the presence of opposite weights neutralising one another. That way of looking at it may be useful from the point of view of later science, but it is not safe to attribute it to the thinkers of the fifth century B.c.
If we no longer regard the “eternal motion” of the
premundane and extramundane atoms as due to their
weight, there is no reason for describing it as a fall.
None of our authorities do as a matter of fact so describe
it, nor do they tell us in any way what it was. It is
safest to say that it is simply a confused motion this
1 This seems to be in the main the view of Dyroff, Demokritstudien (1899), pp. 31 sqq., though I should not say that lightness and weight only arose in connexion with the atoms of the earth (p. 35). If we substitute ‘© world” for *‘ earth,” we shall be nearer the truth,
2 See above, p. 390.
Leukippos of Miletos 399
way and that.’ It is possible that the comparison of
the motion of the atoms of the soul to that of the
motes in a sunbeam coming through a window, which
Aristotle attributes to Demokritos,’ is really intended
as an illustration of the original motion of the atoms
still surviving in the soul. The fact that it is also a
_ Pythagorean comparison? in no way tells against this ;
for we have seen that there is a real connexion
between the Pythagorean monads and the atoms. It is
also significant that the point of the comparison appears
to have been the fact that the motes in the sunbeam
move even when there is no wind, so that it would be
a very apt illustration indeed of the motion inherent in
— eS T.).hClUle
the atoms apart from the secondary motions produced by
impact and collision. That, however, is problematical ;
it only serves to suggest the sort of motion which it
is natural to suppose that Leukippos gave his atoms.
180. But what are we to say of the vortex itself The vortex.
which produces these effects? Gomperz observes that
they seem to be “the precise contrary of what they
should have been by the laws of physics”; for, “as
every centrifugal machine would show, it is the heaviest
1 This view was independently advocated by Brieger (Die Urbewegung der Atome und die Weltentstehung bet Leucipp und Demokrit, 1884) and Liepmann (Die Mechanik der Leucipp-Demokritschen Atome, 1885), both of whom unnecessarily weakened their position by admitting that weight is an original property of the atoms. On the other hand, Brieger denies that the weight of the atoms is the cause of their original motion, while Liepmann says that before and outside the vortex there is only a latent weight, a Pseudoschwere, which only comes into operation in the world. It is surely simpler to say that this weight, since it produces no effect, does not yet exist. Zeller rightly argues against Brieger and Liepmann that, if the atoms have weight, they must fall; but, so far as I can see, nothing he says tells against their theory as I have restated it, Gomperz adopts the Brieger-Liepmann explanation, See also Lortzing, Jahresber., 1903, pp. 136 sqq.
2 Arist. de An. A, 2. 403 b 28 sqq. (R. P. 200).
8 bid, A, 2. 404 ἃ 17 (ΚΕ. P. 86 8).
400 Early Greek Philosophy
substances which are hurled to the greatest distance.” *
Are we to suppose that Leukippos was ignorant of this
fact, which was known to Anaxagoras, though Gomperz
is wrong in supposing there is any reason to believe
that Anaximander took account of it?? Now we
know from Aristotle that all those who accounted for
the earth being in the centre of the world by means
of a vortex appealed to the analogy of eddies in wind
or water,®? and Gomperz supposes that the whole theory
was an erroneous generalisation of this observation. If
we look at the matter more closely, we can see, I think,
that there is no error at all.
We must remember that all the parts of the vortex
are in contact, and that it is just this contact (ἐπίψαυσις)
by which the motion of the outermost parts is com-
municated to those within them. The larger bodies
are more able to resist this communicated motion than
the smaller, and in this way they make their way to
the centre where the motion is least, and force the
smaller bodies out. This resistance is surely just the
ἀντέρεισις τοῦ μέσου which is mentioned in the doxo-
graphy of Leukippos,* and it is quite in accordance
with this that, on the atomist theory, the nearer a
heavenly body is to the centre, the slower is its
revolution.” There is no question of “centrifugal
1 Gomperz, Greek Thinkers, i. p. 339.
2 For Empedokles, see Chap. V. p. 274; Anaxagoras, see Chap. VI. Ρ. 312; and for Anaximander, Chap. I. p. 69, n. 1.
3 Arist. de Caelo, B, 13. 295 a 10, ταύτην γὰρ τὴν αἰτίαν (sc. τὴν δίνησιν) πάντες λέγουσιν ἐκ τῶν ἐν τοῖς ὑγροῖς Kal περὶ τὸν ἀέρα συμβαι- νόντων ᾿ ἐν τούτοις γὰρ ἀεὶ φέρεται τὰ μείζω καὶ τὰ βαρύτερα πρὸς τὸ μέσον τῆς δίνης.
4 Diog. ix. 32. Cf. especially the phrases ὧν κατὰ τὴν τοῦ μέσου ἀντέρεισιν περιδινουμένων, συμμενόντων ἀεὶ τῶν συνεχῶν κατ᾽ ἐπίψαυσιν
τῆς δίνης, and συμμενόντων τῶν ἐνεχθέντων ἐπὶ τὸ μέσον. 5 Cf. Lucr. v. 621 564.
Leukippos of Miletos 401
force” at all, and the analogy of eddies in air and water is quite satisfactory.
181. When we come to details, the reactionary
character of the atomist cosmology is very manifest.
The earth was shaped like a tambourine, and floated
on the air." It was inclined towards the south because
the heat of that region made the air thinner, while the
ice and cold of the north made it denser and more
able to support the earth. This accounts for the
obliquity of the zodiac. Like Anaximander (§ 19),
Leukippos held that the sun was further away than the
stars, though he also held that these were further
away than the moon. This certainly suggests that he
made no clear distinction between the planets and the
fixed stars. He does, however, appear to have known
the theory of eclipses as given by Anaxagoras.‘
Such other pieces of information as have come down
to us are mainly of interest as showing that, in some
important respects, the doctrine of Leukippos was not
_the same as that taught afterwards by Demokritos.°
182. Aetios expressly attributes to Leukippos the
1 Aet. iii. 3, 10, quoted above, p. 83, n. 2. 2 Aet. iii, 12, 1, Λεύκιππος παρεκπεσεῖν τὴν γῆν els τὰ μεσημβρινὰ
Μέρη διὰ τὴν ἐν τοῖς μεσημβρινοῖς ἀραιότητα, dre δὴ πεπηγότων τῶν
8 Diog. ix. 33, εἶναι δὲ τὸν τοῦ ἡλίου κύκλον ἐξώτατον, τὸν δὲ τῆς σελήνης προσγειότατον, {τοὺς 5é> τῶν ἄλλων μεταξὺ τούτων.
4 From Diog., Joc. cit. (supra, p. 391), it appears that he dealt with the
question of the greater frequency of lunar as compared with solar eclipses. - It seems to have been this which led him to make the circle of the moon - smaller than that of the stars.
5 Diels pointed out that Leukippos’s explanation of thunder (πυρὸς ἐναποληφθέντος νέφεσι παχυτάτοις ἔκπτωσιν ἰσχυρὰν βροντὴν ἀποτελεῖν ἀποφαίνεται, Aet. iii. 3, 10) is quite different from that οἵ Demokritos (βροντὴν. . . ἐκ συγκρίματος ἀνωμάλου τὸ περιειληφὸς αὐτὸ νέφος πρὸς τὴν κάτω φορὰν ἐκβιαζομένου, ἐδ. 11). The explanation given by Leukippos
_ is derived from that of Anaximander, while Demokritos is influenced by | Anaxagoras. See Diels, 35 Phélol.- Vers. 97, 7.
The earth and
the heavenly
bodies.
Perception.
402 Early Greek Philosophy
doctrine that the objects of sense-perception exist “ by
law” and not by nature’ This must come from
Theophrastos ; for, as we have seen, all later writer:
quote Demokritos only. A further proof of the
correctness of the statement is that we also finc
it attributed to Diogenes of Apollonia, who, a:
Theophrastos tells us, derived some of his views from
Leukippos. There is nothing surprising in this
Parmenides had already declared the senses to be
deceitful, and said that colour and the like were only
” 2 and Empedokles had also spoken of coming
“ names,
into being and passing away as only “names.”? I
is not likely that Leukippos went much further thar
this. It would probably be wrong to credit him with
Demokritos’s clear distinction between genuine anc
“bastard” knowledge, or that between what are now
called the primary and secondary qualities of matter.’
These distinctions imply a conscious epistemologica!
theory, and all we are entitled to say is that the germ:
of this were already to be found in the writings Οἱ
Leukippos and his predecessors. Of course, these dc
not make Leukippos a sceptic any more than Em-
pedokles or Anaxagoras, whose remark on this subject
(fr. 21a) Demokritos is said to have quoted witl
approval.°
There appear to be sufficient grounds for ascribing:
1 Aet. iv. 9, 8, of μὲν ἄλλοι φύσει τὰ αἰσθητα, Λεύκιππος δὲ Δημόκριτο: καὶ ᾿Απολλώνιος νόμῳ. See Zeller, Arch. ν. p. 444.
2 Chap. IV. p. 200, ἢ. 3. The remarkable parallel quoted by Gomper: (p. 321) from Galilei, to the effect that tastes, smells, and colours om séen: altro che puri nomi should, therefore, have been cited to illustrat: Parmenides rather than Demokritos.
3 See p. 240, fr. 8.
4 For these see Sext. Jazh. vii. 135 (R. P. 204).
5 Sext. vii. 140, ““ ὄψις yap ἀδήλων τὰ φαινόμενα," ὥς φησιν ’Avataryédpa.:, ὃν ἐπὶ τούτῳ Δημόκριτος ἐπαινεῖ.
Leukippos of Miletos 403
the theory of perception by means of simulacra or
εἴδωλα, which played such a part in the systems of
Demokritos and Epicurus, to Leukippos.’ It is a very
natural development of the Empedoklean theory of |
“effluences” (§ 118). It hardly seems likely, however, |
that he went into great detail on the subject, and it
is safer to credit Demokritos with the elaboration of the
theory.
183. We have seen incidentally that there is a wide Importance of
divergence of opinion among recent writers as to the ——
place of Atomism in Greek thought. The question at
_ issue is really whether Leukippos reached his theory
on what are called “metaphysical grounds,” that is,
from a consideration of the Eleatic theory of reality, or
whether, on the contrary, it was a pure development of
Ionian science. The foregoing exposition will suggest
the true answer. So far as his general theory of the
physical constitution of the world is concerned, it has
been shown, I think, that it was derived entirely from
Eleatic and Pythagorean sources, while the detailed
cosmology was in the main a more or less successful
attempt to make the older Ionian beliefs fit into this
new physical theory. In any case, his greatness
consisted in his having been the first to see how body
must be regarded if we take it to be ultimate reality.
The old Milesian theory had found its most adequate
expression in the system of Anaximenes (§ 31), but of
course rarefaction and condensation cannot be clearly
represented except on the hypothesis of molecules or
atoms coming closer together or going further apart in