Chapter IX: Leukippos of Miletos

[Sidenote: Leukippos and Demokritos.]

171. We have seen (§§ 31, 122) that the school of Miletos did not come to an end with Anaximenes, and it is a striking fact that the man who gave the most complete answer to the question first asked by Thales was a Milesian.[921] It is true that the very existence of Leukippos has been called in question. Epicurus said there never was such a philosopher, and the same thing has been maintained in quite recent times.[922] On the other hand, Aristotle and Theophrastos certainly made him the originator of the atomic theory, and it still seems possible to show they were right. Incidentally we shall see how later writers came to ignore him, and thus made possible the sally of Epicurus.

Footnote 921:

Theophrastos said he was an Eleate or a Milesian (R. P. 185), while
Diogenes (ix. 30) says he was an Eleate or, according to some, an
Abderite. These statements are exactly parallel to the discrepancies
about the native cities of the Pythagoreans already noted (Chap. VII.
p. 327, _n._ 763). Diogenes adds that, according to others, Leukippos
was a Melian, which is a common confusion. Aetios (i. 7. 1) calls
Diagoras of Melos a Milesian (cf. _Dox._ p. 14). Demokritos was called
by some a Milesian (R. P. 186) for the same reason that Leukippos is
called an Eleate. We may also compare the doubt as to whether
Herodotos called himself a Halikarnassian or a Thourian.

Footnote 922:

Diog. x. 13 (R. P. 185 b). The theory was revived by E. Rohde. For the
literature of the controversy, see R. P. 185 b. Diels’s refutation of
Rohde has convinced most competent judges. Brieger’s attempt to
unsettle the question again (_Hermes_, xxxvi. pp. 166 sqq.) is only
half-hearted, and quite unconvincing. As will be seen, however, I
agree with his main contention that atomism comes after the systems of
Empedokles and Anaxagoras.

The question is intimately bound up with that of the date of Demokritos, who said that he was a young man in the old age of Anaxagoras, a statement which makes it unlikely that he founded his school at Abdera before 420 B.C., the date given by Apollodoros for his _floruit_.[923] Now Theophrastos stated that Diogenes of Apollonia borrowed some of his views from Anaxagoras and some from Leukippos,[924] which can only mean that there were traces of the atomic theory in his work. Further, Apollonios is parodied in the _Clouds_ of Aristophanes, which was produced in 423 B.C., from which it follows that the work of Leukippos must have become known considerably before that date. What that work was, Theophrastos also tells us. It was the _Great Diakosmos_ usually attributed to Demokritos.[925] This means further that what were known later as the works of Demokritos were really the writings of the school of Abdera, and included, as was natural, the works of its founder. They formed, in fact, a _corpus_ comparable to that which has come down to us under the name of Hippokrates, and it was no more possible to distinguish the authors of the different treatises in the one case than it is in the other. We need not hesitate, for all that, to believe that Aristotle and Theophrastos were better informed on this point than later writers, who naturally regarded the whole mass as equally the work of Demokritos.

Footnote 923:

Diog. ix. 41 (R. P. 187). As Diels points out, the statement suggests
that Anaxagoras was dead when Demokritos wrote. It is probable, too,
that it was this which made Apollodoros fix the _floruit_ of
Demokritos just forty years after that of Anaxagoras (Jacoby, p. 290).
We cannot make much of the other statement of Demokritos that he wrote
the Μικρὸς διάκοσμος 750 years after the fall of Troy; for we cannot
be sure what era he used (Jacoby, p. 292).

Footnote 924:

Theophr. _ap._ Simpl. _Phys._ p. 25, 1 (R. P. 206 a).

Footnote 925:

This was stated by Thrasylos in his list of the tetralogies in which
he arranged the works of Demokritos, as he did those of Plato. He
gives Tetr. iii. thus: (1) Μέγας διάκοσμος (ὃν οἱ περὶ Θεόφραστον
Λευκίππου φασὶν εἶναι); (2) Μικρὸς διάκοσμος; (3) Κοσμογραφίη; (4)
Περὶ τῶν πλανήτων. The two διάκοσμοι would only be distinguished as
μέγας and μικρός when they came to be included in the same _corpus_. A
quotation purporting to be from the Περὶ νοῦ of Leukippos is preserved
in Stob. i. 160. The phrase ἐν τοῖς Λευκίππου καλουμένοις λόγοις in
_M.X.G._ 980 a 8 seems to refer to Arist. _de Gen. Corr._ 325 a 24,
Λεύκιππος δ’ ἔχειν ᾠήθη λόγους κ.τ.λ., and would prove nothing in any
case. Cf. Chap. II. p. 138, _n._ 305.

Theophrastos found Leukippos described as an Eleate in some of his authorities, and, if we may trust analogy, that means he had settled at Elea.[926] It is possible that his emigration to the west was connected with the revolution at Miletos in 450-49 B.C.[927] In any case, Theophrastos says distinctly that he had been a member of the school of Parmenides, and the way in which he speaks suggests that the founder of that school was still at its head.[928] He may very well have been so, if we accept Plato’s chronology.[929] Theophrastos also appears to have said that Leukippos “heard” Zeno, which is very credible. We shall see, at any rate, that the influence of Zeno on his thinking is unmistakable.[930]

Footnote 926:

See above, p. 380, _n._ 921.

Footnote 927:

The aristocrats had massacred the democrats, and were overthrown in
their turn by the Athenians. Cf. [Xen.] Ἀθ. πολ. 3, 11. The date is
fixed by _C.I.A._ i. 22 a.

Footnote 928:

Theophr. _ap._ Simpl. _Phys._ p. 28, 4 (R. P. 185). Note the
difference of case in κοινωνήσας Παρμενίδῃ τῆς φιλοσοφίας and
κοινωνήσας τῆς Ἀναξιμένους φιλοσοφίας which is the phrase used by
Theophrastos of Anaxagoras (p. 293, _n._ 660). The dative seems to
imply a personal relationship. It is quite inadmissible to render “was
familiar with the doctrine of Parmenides,” as is done in Gomperz,
_Greek Thinkers_, vol. i. p. 345.

Footnote 929:

See § 84.

Footnote 930:

Cf. Diog. ix. 30, οὕτος ἤκουσε Ζήνωνος (R. P. 185 b); and Hipp. _Ref._
i. 12, 1, Λεύκιππος ... Ζήνωνος ἑταῖρος. Diels conjectured that the
name of Zeno had been dropped in the extract from Theophrastos
preserved by Simplicius (_Dox._ 483 a 11).

The relations of Leukippos to Empedokles and Anaxagoras are more difficult to determine. It has become part of the case for the historical reality of Leukippos that there are traces of atomism in the systems of these men; but the case is strong enough without that assumption. Besides, it lands us in serious difficulties, not the least of which is that it would require us to regard Empedokles and Anaxagoras as mere eclectics like Diogenes of Apollonia.[931] The strongest argument for the view that Leukippos influenced Empedokles is that drawn from the doctrine of “pores”; but we have seen that this originated with Alkmaion, and it is therefore more probable that Leukippos derived it from Empedokles.[932] We have seen too that Zeno probably wrote against Empedokles, and we know that he influenced Leukippos.[933] Nor, is it at all probable that Anaxagoras knew anything of the theory of Leukippos. It is true that he denied the existence of the void; but it does not follow that any one had already maintained that doctrine in the atomist sense. The early Pythagoreans had spoken of a void too, though they had confused it with atmospheric air; and the experiments of Anaxagoras with the _klepsydra_ and the inflated skins would only have had any point if they were directed against the Pythagorean theory.[934] If he had really wished to refute Leukippos, he would have had to use arguments of a very different kind.

Footnote 931:

This point is important, though the argument is weakened by Brieger’s
overstatement of it in _Hermes_, xxxvi. p. 183. He says that to assume
such a reaction as Anaxagoreanism after the atomic system had once
been discovered would be something unexampled in the history of Greek
philosophy. Diogenes of Apollonia proves the contrary. The real point
is that Empedokles and Anaxagoras were men of a different stamp. So
far as Empedokles is concerned, Gomperz states the case rightly
(_Greek Thinkers_, vol. i. p. 560).

Footnote 932:

See above, Chap. V. p. 224, _n._ 492; and Brieger in _Hermes_, xxxvi.
p. 171.

Footnote 933:

Diels (formerly at least) maintained both these things. See above, p.
359, _n._ 859; and p. 382, _n._ 930. If, as seems probable (§ 158),
Zeno wrote his book some time between 470 and 460 B.C., Leukippos can
hardly have written his before 450 B.C., and even that is too late for
him to have influenced Empedokles. It may well have been later still.

Footnote 934:

See above, Chap. VI. § 131; and Chap. VII. § 145.

[Sidenote: Theophrastos on the atomic theory.]

172. Theophrastos wrote of Leukippos as follows in the First Book of his _Opinions_:—

Leukippos of Elea or Miletos (for both accounts are given of him) had
associated with Parmenides in philosophy. He did not, however, follow
the same path in his explanation of things as Parmenides and
Xenophanes did, but, as is believed, the very opposite (R. P. 185).
They made the All one, immovable, uncreated, and finite, and did not
even permit us to search for _what is not_; he assumed innumerable and
ever-moving elements, namely, the atoms. And he made their forms
infinite in number, since there was no reason why they should be of
one kind rather than another, and because he saw that there was
unceasing becoming and change in things. He held, further, that _what
is_ is no more real than _what is not_, and that both are alike causes
of the things that come into being; for he laid down that the
substance of the atoms was compact and full, and he called them _what
is_, while they moved in the void which he called _what is not_, but
affirmed to be just as real as _what is_. R. P. 194.

[Sidenote: Leukippos and the Eleatics.]

173. It will be observed that Theophrastos, while noting the affiliation of Leukippos to the Eleatic school, points out that his theory is, _prima facie_,[935] just the opposite of that maintained by Parmenides. Some have been led by this to deny the Eleaticism of Leukippos altogether; but this denial is really based on the view that the system of Parmenides was “metaphysical,” coupled with a great reluctance to admit that so scientific a hypothesis as the atomic theory can have had a “metaphysical” origin. It is really due to prejudice, and we must not suppose Theophrastos himself believed the two theories to be so far apart as they seem.[936] As this is really the most important point in the history of early Greek philosophy, and as, rightly understood, it furnishes the key to the whole development, it is worth while to transcribe a passage of Aristotle[937] which explains the historical connexion in a way that leaves nothing to be desired.

Footnote 935:

The words ὡς δοκεῖ do not imply assent to the view introduced by them;
indeed they are used, far more often than not, in reference to beliefs
which the writer does not accept. The translation “methinks” in
Gomperz, _Greek Thinkers_, vol. i. p. 345, is therefore most
misleading, and there is no justification for Brieger’s statement
(_Hermes_, xxxvi. p. 165) that Theophrastos dissents from Aristotle’s
view as given in the passage about to be quoted. We should be saved
from many errors if we accustomed ourselves to translate δοκεῖ by “is
thought” or “is believed” instead of by “seems.”

Leukippos and Demokritos have decided about all things practically by
the same method and on the same theory, taking as their starting-point
what naturally comes first. Some of the ancients had held that the
real must necessarily be one and immovable; for, said they, empty
space is not real, and motion would be impossible without empty space
separated from matter; nor, further, could reality be a many, if there
were nothing to separate things. And it makes no difference if any one
holds that the All is not continuous, but discrete, with its parts in
contact (_the Pythagorean view_), instead of holding that reality is
many, not one, and that there is empty space. For, if it is divisible
at every point there is no one, and therefore no many, and the Whole
is empty (_Zeno_); while, if we say it is divisible in one place and
not in another, this looks like an arbitrary fiction; for up to what
point and for what reason will part of the Whole be in this state and
be full, while the rest is discrete? And, on the same grounds, they
further say that there can be no motion. In consequence of these
reasonings, then, going beyond perception and overlooking it in the
belief that we ought to follow the argument, they say that the All is
one and immovable (_Parmenides_), and some of them that it is infinite
(_Melissos_), for any limit would be bounded by empty space. This,
then, is the opinion they expressed about the truth, and these are the
reasons which led them to do so. Now, so far as arguments go, this
conclusion does seem to follow; but, if we appeal to facts, to hold
such a view looks like madness. No one who is mad is so far out of his
senses that fire and ice appear to him to be one; it is only things
that are right, and things that appear right from habit, in which
madness makes some people see no difference.

Leukippos, however, thought he had a theory which was in harmony with
sense-perception, and did not do away with coming into being and
passing away, nor motion, nor the multiplicity of things. He made this
concession to experience, while he conceded, on the other hand, to
those who invented the One that motion was impossible without the
void, that the void was not real, and that nothing of what was real
was not real. “For,” said he, “that which is strictly speaking real is
an absolute _plenum_; but the _plenum_ is not one. On the contrary,
there are an infinite number of them, and they are invisible owing to
the smallness of their bulk. They move in the void (for there is a
void); and by their coming together they effect coming into being; by
their separation, passing away.”

Footnote 936:

This prejudice is apparent all through Gomperz’s _Greek Thinkers_, and
seriously impairs the value of that fascinating, though somewhat
imaginative work. It is amusing to notice that Brieger, from the same
point of view, regards the custom of making Anaxagoras the last of the
Presocratics as due to theological prepossessions (_Hermes_, xxxvi. p.
185). I am sorry that I cannot agree with either side; but the
bitterness of the disputants bears witness to the fundamental
importance of the questions raised by the early Greek philosophers.

Footnote 937:

Arist. _de Gen. Corr._ Α, 8. 324 b 35 (R. P. 193).

It is true that in this passage Zeno and Melissos are not named, but the reference to them is unmistakable. The argument of Zeno against the Pythagoreans is clearly given; and Melissos was the only Eleatic who made reality infinite, a point which is distinctly mentioned. We are therefore justified by Aristotle’s words in explaining the genesis of Atomism and its relation to Eleaticism as follows. Zeno had shown that all pluralist systems yet known, and especially Pythagoreanism, were unable to stand before the arguments from infinite divisibility which he adduced. Melissos had used the same argument against Anaxagoras, and had added, by way of _reductio ad absurdum_, that, if there were many things, each one of them must be such as the Eleatics held the One to be. To this Leukippos answers, “Why not?” He admitted the force of Zeno’s arguments by setting a limit to divisibility, and to each of the atoms which he thus arrived at he ascribed all the predicates of the Eleatic One; for Parmenides had shown that if _it is_, it must have these predicates somehow. The same view is implied in a passage of Aristotle’s _Physics_.[938] “Some,” we are there told, “surrendered to both arguments, to the first, the argument that all things are one, if the word _is_ is used in one sense only (_Parmenides_), by affirming the reality of what is not; to the second, that based on dichotomy (_Zeno_), by introducing indivisible magnitudes.” Finally, it is only by regarding the matter in this way that we can attach any meaning to another statement of Aristotle’s to the effect that Leukippos and Demokritos, as well as the Pythagoreans, virtually make all things out of numbers.[939] Leukippos, in fact, gave the Pythagorean monads the character of the Parmenidean One.

Footnote 938:

Arist. _Phys._ Α, 3. 187 a 1 (R. P. 134 b).

Footnote 939:

Arist. _de Caelo_, Γ, 4. 303 a 8, τρόπον γάρ τινα καὶ οὕτοι (Λεύκιππος
καὶ Δημόκριτος) πάντα τὰ ὄντα ποιοῦσιν ἀριθμοὺς καὶ ἐξ ἀριθμῶν. This
also serves to explain what Herakleides may have meant by attributing
the theory of corporeal ὄγκοι to the Pythagorean Ekphantos of Syracuse
(above, p. 338, _n._ 794).

[Sidenote: Atoms.]

174. We must observe that the atom is not mathematically indivisible, for it has magnitude; it is, however, physically indivisible, because, like the One of Parmenides, it contains in it no empty space.[940] Each atom has extension, and all the atoms are exactly alike in substance.[941] Therefore all differences in things must be accounted for either by the shape of the atoms or by their arrangement. It seems probable that the three ways in which differences arise, namely, shape, position, and arrangement, were already distinguished by Leukippos; for Aristotle mentions his name in connexion with them.[942] This explains, too, why the atoms are called “forms” or “figures,” a way of speaking which seems to be of Pythagorean origin.[943] That they are also called φύσις[944] is quite intelligible if we remember what was said of that word in the Introduction (§ VII.). The differences in shape, order, and position just referred to account for the “opposites,” the “elements” being regarded rather as aggregates of these (πανσπερμίαι), as by Anaxagoras.[945]

Footnote 940:

The Epicureans misunderstood this point, or misrepresented it in order
to magnify their own originality (see Zeller, p. 857, n. 3; Eng.
trans. ii. p. 225, n. 2).

Footnote 941:

Arist. _de Caelo_, Α, 7. 275 b 32, τὴν δὲ φύσιν εἶναί φασιν αὐτῶν
μίαν; _Phys._ Γ, 4. 203 a 34, αὐτῷ (Δημοκρίτῳ) τὸ κοινὸν σῶμα πάντων
ἐστὶν ἀρχή.

Footnote 942:

Arist. _Met._ Α, 4. 985 b 13 (R. P. 192); cf. _de Gen. Corr._ 315 b 6.
As Diels suggests, the illustration from the letters of the alphabet
is probably due to Demokritos. It shows, in any case, how the word
στοιχεῖον came to be used later for “element.” We must read, with
Wilamowitz, τὸ δὲ Ζ τοῦ Η θέσει for τὸ δὲ Ζ τοῦ Ν θέσει, the older
form of the letter Ζ being just an Η laid upon its side (Diels,
_Elementum_, p. 13, n. 1).

Footnote 943:

Demokritos wrote a work, Περὶ ἰδεῶν (Sext. _Math._ vii. 137; R. P.
204), which Diels identifies with the Περὶ τῶν διαφερόντων ῥυσμῶν of
Thrasylos, _Tetr._ v. 3. Theophrastos refers to Demokritos, ἐν τοῖς
περὶ τῶν εἰδῶν (_de Sensibus_, § 51). Plut. _adv. Col._ 1111 a, εἶναι
δὲ πάντα τὰς ἀτόμους, ἰδέας ὑπ’ αὐτοῦ καλουμένας (so the MSS.: ἰδίως,
Wyttenbach; <ἢ> ἰδέας, Diels). Arist. Phys. Γ, 4. 203 a 21,
(Δημόκριτος) ἐκ τῆς πανσπερμίας τῶν σχημάτων (ἄπειρα ποιεῖ τὰ
στοιχεῖα). Cf. _de Gen. Corr._ Α, 2. 315 b 7 (R. P. 196).

Footnote 944:

Arist. _Phys._ Θ, 9. 265 b 25; Simpl. _Phys._ p. 1318, 33, ταῦτα γὰρ
(τὰ ἄτομα σώματα) ἐκεῖνοι φύσιν ἐκάλουν.

Footnote 945:

Simpl. _Phys._ p. 36, 1 (Diels, _Vors._ p. 346), and R. P. 196 a.

[Sidenote: The void.]

175. Leukippos affirmed the existence both of the Full and the Empty, terms which he may have borrowed from Melissos.[946] As we have seen, he had to assume the existence of empty space, which the Eleatics had denied, in order to make his explanation of the nature of body possible. Here again he is developing a Pythagorean view. The Pythagoreans had spoken of the void, which kept the units apart; but they had not distinguished it from atmospheric air (§ 53), which Empedokles had shown to be a corporeal substance (§ 107). Parmenides, indeed, had formed a clearer conception of space, but only to deny its reality. Leukippos started from this. He admitted, indeed, that space was not real, that is to say, corporeal; but he maintained that it existed all the same. He hardly, it is true, had words to express his discovery in; for the verb “to be” had hitherto been used by philosophers only of body. But he did his best to make his meaning clear by saying that “what is not” (in the old corporealist sense) “is” (in another sense) just as much as “what is.” The void is as real as body.

Footnote 946:

Arist. _Met._ Α, 4. 985 b 4 (R. P. 192). Cf. Melissos, fr. 7 _sub
fin._

It is a curious fact that the Atomists, who are commonly regarded as the great materialists of antiquity, were actually the first to say distinctly that a thing might be real without being a body.

[Sidenote: Cosmology.]

176. It might seem a hopeless task to disentangle the cosmology of Leukippos from that of Demokritos, with which it is generally identified; but that very fact affords an invaluable clue. So far as we know, no one after Theophrastos was able to distinguish the doctrines of the two men, and it follows from this that all definite statements about Leukippos in later writers must, in the long run, go back to him. If we follow this up, we shall be able to give a fairly clear account of the system, and we shall even come across some views which are peculiar to Leukippos and were not adopted by Demokritos.[947]

Footnote 947:

Cf. Zeller, “Zu Leukippus” (_Arch._ xv. p. 138).

We shall start from the fuller of the two doxographies in Diogenes, which comes from an epitome of Theophrastos.[948] It is as follows:—

He says that the All is infinite, and that it is part full, and part
empty. These (the full and the empty), he says, are the elements. From
them arise innumerable worlds and are resolved into them. The worlds
come into being thus. There were borne along by “abscision from the
infinite” many bodies of all sorts of figures “into a mighty void,”
and they being gathered together produce a single vortex. In it, as
they came into collision with one another and were whirled round in
all manner of ways, those which were alike were separated apart and
came to their likes. But, as they were no longer able to revolve in
equilibrium owing to their multitude, those of them that were fine
went out to the external void, as if passed through a sieve; the rest
stayed together, and becoming entangled with one another, ran down
together, and made a first spherical structure. This was in substance
like a membrane or skin containing in itself all kinds of bodies. And,
as these bodies were borne round in a vortex, in virtue of the
resistance of the middle, the surrounding membrane became thin, as the
contiguous bodies kept flowing together from contact with the vortex.
And in this way the earth came into being, those things which had been
borne towards the middle abiding there. Moreover, the containing
membrane was increased by the further separating out of bodies from
outside; and, being itself carried round in a vortex, it further got
possession of all with which it had come in contact. Some of these
becoming entangled, produce a structure, which was at first moist and
muddy; but, when they had been dried and were revolving along with the
vortex of the whole, they were then ignited and produced the substance
of the heavenly bodies. The circle of the sun is the outermost, that
of the moon is nearest to the earth, and those of the others are
between these. And all the heavenly bodies are ignited because of the
swiftness of their motion; while the sun is also ignited by the stars.
But the moon only receives a small portion of fire. The sun and the
moon are eclipsed.... (And the obliquity of the zodiac is produced) by
the earth being inclined towards the south; and the northern parts of
it have constant snow and are cold and frozen. And the sun is eclipsed
rarely, and the moon continually, because their circles are unequal.
And just as there are comings into being of the world, so there are
growths and decays and passings away in virtue of a certain necessity,
of the nature of which he gives no clear account.

Footnote 948:

Diog. ix. 31 sqq. (R. P. 197, 197 c). This passage deals expressly
with Leukippos, not with Demokritos or even “Leukippos and
Demokritos.” For the distinction between the “summary” and “detailed”
doxographies in Diogenes, see Appendix, § 15.

As it comes substantially from Theophrastos, this passage is to be regarded as good evidence for the cosmology of Leukippos, and it is confirmed in an interesting way by certain Epicurean extracts from the _Great Diakosmos_.[949] These, however, as is natural, give a specially Epicurean turn to some of the doctrines, and must therefore be used with caution.

Footnote 949:

These are to be found in Aet. i. 4 (_Dox._ p. 289; _Vors._ p. 347;
Usener, _Epicurea_, fr. 308). Epicurus himself in the second epistle
(Diog. x. 88; Usener, p. 37, 7) quotes the phrase ἀποτομὴν ἔχουσα ἀπὸ
τοῦ ἀπείρου.

[Sidenote: Relation to Ionic cosmology.]

177. The general impression which we get from the cosmology of Leukippos is that he either ignored or had never heard of the great advance in the general view of the world which was due to the later Pythagoreans. He is as reactionary in his detailed cosmology as he was daring in his general physical theory. We seem to be reading once more of the speculations of Anaximenes or even of Anaximander, though there are traces of Empedokles and Anaxagoras too. The explanation is not hard to see. Leukippos would not learn a cosmology from his Eleatic teachers; and, even when he found it possible to construct one without giving up the Parmenidean view of reality, he was necessarily thrown back upon the older systems of Ionia. The result was unfortunate. The astronomy of Demokritos, so far as we know it, was still of this childish character. There is no reason to doubt the statement of Seneca that he did not venture to say how many planets there were.[950]

Footnote 950:

Seneca, _Q. Nat._ vii. 3.

This, I take it, is what gives plausibility to Gomperz’s statement that Atomism was “the ripe fruit on the tree of the old Ionic doctrine of matter which had been tended by the Ionian physiologists.”[951] The detailed cosmology was certainly such a fruit, and it was possibly over-ripe; but the atomic theory proper, in which the real greatness of Leukippos comes out, was wholly Eleatic in its origin. Nevertheless, it will repay us to examine the cosmology too; for such an examination will serve better than anything else to bring out the true nature of the historical development of which it was the outcome.

Footnote 951:

Gomperz, _Greek Thinkers_, vol. i. p. 323.

[Sidenote: The eternal motion.]

178. Leukippos represented the atoms as having been always in motion. Aristotle puts this in his own way. The atomists, he says, “indolently” left it unexplained what was the source of motion, and they did not say what sort of motion it was. In other words, they did not decide whether it was a “natural motion” or one impressed on them “contrary to their nature.”[952] He even went so far as to say that they made it “spontaneous,” a remark which has given rise to the erroneous view that they held it was due to chance.[953] Aristotle does not say that, however; but only that the atomists did not explain the motion of the atoms in any of the ways in which he himself explained the motion of the elements. They neither ascribed to them a natural motion like the circular motion of the heavens and the rectilinear motion of the four elements in the sublunary region, nor did they give them a forced motion contrary to their own nature, like the upward motion which may be given to the heavy elements and the downward which may be given to the light. The only fragment of Leukippos which has survived is an express denial of chance. “Naught happens for nothing,” he said “but everything from a ground and of necessity.”[954]

Footnote 952:

Arist. _Phys._ Θ, 1. 252 a 32 (R. P. 195 a); _de Caelo_, Γ, 2. 300 b 8
(R. P. 195); _Met._ Α, 4. 985 b 19 (R. P. _ib._).

Footnote 953:

Arist. _Phys._ Β, 4. 196 a 24 (R. P. 195 d). Cicero, _de nat. D._ i.
66 (R. P. _ib._). The latter passage is the source of the phrase
“fortuitous concourse” (_concurrere_ = συντρέχειν).

Footnote 954:

Aet. i. 25, 4 (_Dox._ p. 321), Λεύκιππος πάντα κατ’ ἀνάγκην, τὴν δ’
αὐτὴν ὑπάρχειν εἱμαρμένην. λέγει γὰρ ἐν τῷ Περὶ νοῦ· Οὐδὲν χρῆμα μάτην
γίγνεται, ἀλλὰ πάντα ἐκ λόγου τε καὶ ὑπ’ ἀνάγκης.

If we put the matter historically, all this means that Leukippos did not, like Empedokles and Anaxagoras, find it necessary to assume a force to originate motion. He had no need of Love and Strife or Mind, and the reason is clear. Though Empedokles and Anaxagoras had tried to explain multiplicity and motion, they had not broken so radically as Leukippos did with the Parmenidean One. Both of them started with a condition of matter in which the “roots” or “seeds” were mixed so as to be “all together,” and they therefore required something to break up this unity. Leukippos, who started with an infinite number of Parmenidean “Ones,” so to speak, required no external agency to separate them. What he had to do was just the opposite. He had to give an explanation of their coming together, and there was nothing so far to prevent his return to the old and natural idea that motion does not require any explanation at all.[955]

Footnote 955:

Introd. § VIII.

This, then, is what seems to follow from the criticisms of Aristotle and from the nature of the case; but it will be observed that it is not consistent with Zeller’s opinion that the original motion of the atoms is a fall through infinite space, as in the system of Epicurus. Zeller’s view depends, of course, on the further belief that the atoms have weight, and that weight is the tendency of bodies to fall, so we must go on to consider whether and in what sense weight is a property of the atoms.

[Sidenote: The weight of the atoms.]

179. As is well known, Epicurus held that the atoms were naturally heavy, and therefore fell continually in the infinite void. The school tradition is, however, that the “natural weight” of the atoms was an addition made by Epicurus himself to the original atomic system. Demokritos, we are told, assigned two properties to atoms, magnitude and form, to which Epicurus added a third, weight.[956] On the other hand, Aristotle distinctly says in one place that Demokritos held the atoms were heavier “in proportion to their excess,” and this seems to be explained by the statement of Theophrastos that, according to him, weight depended on magnitude.[957] It will be observed that, even so, it is not represented as a primary property of the atoms in the same sense as magnitude.

Footnote 956:

Aet. i. 3, 18 (of Epicurus), συμβεβηκέναι δὲ τοῖς σώμασι τρία ταῦτα,
σχῆμα, μέγεθος, βάρος. Δημόκριτος μὲν γὰρ ἔλεγε δύο, μέγεθός τε καὶ
σχῆμα, ὁ δὲ Ἐπίκουρος τούτοις καὶ τρίτον βάρος προσέθηκεν· ἀνάγκη γάρ,
φησί, κινεῖσθαι τὰ σώματα τῇ τοῦ βάρους πληγῇ· ἐπεὶ (“or else”) οὐ
κινηθήσεται; _ib._ 12, 6, Δημόκριτος τὰ πρῶτά φησι σώματα, ταῦτα δ’ ἦν
τὰ ναστά, βάρος μὲν οὐκ ἔχειν, κινεῖσθαι δὲ κατ’ ἀλληλοτυπίαν ἐν τῷ
ἀπείρῳ. Cic. _de fato_, 20, “vim motus habebant (atomi) a Democrito
impulsionis quam plagam ille appellat, a te, Epicure, gravitatis et
ponderis.” These passages represent the Epicurean school tradition,
which would hardly venture to misrepresent Demokritos on so important
a point. His works were still accessible. It is confirmed by the
Academic tradition in _de Fin._ i. 17 that Demokritos taught the atoms
moved “in infinito inani, in quo nihil nec summum nec infimum nec
medium nec extremum sit.” This doctrine, we are told, was “depraved”
by Epicurus.

Footnote 957:

Arist. _de Gen. Corr._ 326 a 9, καίτοι βαρύτερόν γε κατὰ τὴν ὑπεροχήν
φησιν εἶναι Δημόκριτος ἕκαστον τῶν ἀδιαιρέτων. I cannot believe this
means anything else than what Theophrastos says in his fragment on
sensation, § 61 (R. P. 199), βαρὺ μὲν οὖν καὶ κοῦφον τῷ μεγέθει
διαιρεῖ Δημόκριτος.

It is impossible to solve this apparent contradiction without referring briefly to the history of Greek ideas about weight. It is clear that lightness and weight would be among the very first properties of body to be distinctly recognised as such. The necessity of lifting burdens must very soon have led men to distinguish them, though no doubt in some primitive and more or less animistic form. Both weight and lightness would be thought of as _things_ that were _in_ bodies. Now it is a remarkable feature of early Greek philosophy that from the first it was able to shake itself free from this idea. Weight is never spoken of as a “thing” as, for instance, warmth and cold are; and, so far as we can see, not one of the thinkers we have studied hitherto thought it necessary to give any explanation of it at all, or even to say anything about it.[958] The motions and resistances which popular theory ascribes to weight are all explained in some other way. Aristotle distinctly declares that none of his predecessors had said anything of absolute weight and lightness. They had only treated of the relatively light and heavy.[959]

Footnote 958:

In Aet. i. 12, where the _placita_ regarding the heavy and light are
given, no philosopher earlier than Plato is referred to. Parmenides
(fr. 8, 59) speaks of the dark element as ἐμβριθές. I do not think
that there is any other place where weight is even mentioned in the
fragments of the early philosophers.

Footnote 959:

Arist. _de Caelo_, 308 a 9, περὶ μὲν οὖν τῶν ἁπλῶς λεγομένων (βαρέων
καὶ κούφων) οὐδὲν εἴρηται παρὰ τῶν πρότερον.

This way of regarding the popular notions of weight and lightness is clearly formulated for the first time in Plato’s _Timaeus_.[960] There is no such thing in the world, we are told there, as “up” or “down.” The middle of the world is not “down” but “just in the middle,” and there is no reason why any point in the circumference should be said to be “above” or “below” another. It is really the tendency of bodies towards their kin that makes us call a falling body heavy and the place to which it falls “below.” Here Plato is really giving the view which was taken more or less consciously by his predecessors, and it is not till the time of Aristotle that it is questioned.[961] For reasons which do not concern us here, he definitely identified the circumference of the heavens with “up” and the middle of the world with “down,” and equipped the four elements with natural weight and lightness that they might perform their rectilinear motions between them. As, however, Aristotle believed there was only one world, and as he did not ascribe weight to the heavens proper, the effect of this reactionary theory upon his cosmical system was not great; it was only when Epicurus tried to combine it with the infinite void that its true character emerged. It seems to me that the nightmare of Epicurean atomism can only be explained on the assumption that an Aristotelian doctrine was violently adapted to a theory which really excluded it.[962] It is totally unlike anything we meet with in earlier days.

Footnote 960:

Plato, _Tim._ 61 c 3 sqq.

Footnote 961:

Zeller says (p. 876) that in antiquity no one ever understood by
weight anything else than the property of bodies in virtue of which
they move downwards; except that in such systems as represent all
forms of matter as contained in a sphere, “above” is identified with
the circumference and “below” with the centre. As to that, I can only
say that no such theory of weight is to be found in the fragments of
the early philosophers or is anywhere ascribed to them, while Plato
expressly denies it.

This brief historical survey suggests at once that it is only in the vortex that the atoms acquire weight and lightness,[963] which are, after all, only popular names for facts which can be further analysed. We are told that Leukippos held that one effect of the vortex was that like atoms were brought together with their likes.[964] In this way of speaking we seem to see the influence of Empedokles, though the “likeness” is of another kind. It is the finer atoms that are forced to the circumference, while the larger tend to the centre. We 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.[965]

Footnote 962:

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.

Footnote 963:

In dealing with Empedokles, Aristotle expressly makes this
distinction. Cf. _de Caelo_, Β, 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 ἥ γε δίνη πλησιάζει πρὸς ἡμᾶς), nor for the
weight of bodies before the vortex arose (πρὶν γενέσθαι τὴν δίνην).

Footnote 964:

Diog., _loc. cit._ (p. 390).

Footnote 965:

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.

There is a striking confirmation of the view just given in the atomist cosmology quoted above.[966] 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 ἰσορροπία 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.

Footnote 966:

See above, p. 390.

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 way and that.[967] 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,[968] 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[969] 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 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.

Footnote 967:

This view was independently advocated by Brieger (_Die Urbewegung der
Atome und die Weltentstehung bei 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.

Footnote 968:

Arist. _de An._ Α, 2. 403 b 28 sqq. (R. P. 200).

Footnote 969:

_Ibid._ Α, 2. 404 a 17 (R. P. 86 a).

[Sidenote: The vortex.]

180. But what are we to say of the vortex itself 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 substances which are hurled to the greatest distance.”[970] 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?[971] 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,[972] 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.

Footnote 970:

Gomperz, _Greek Thinkers_, i. p. 339.

Footnote 971:

For Empedokles, see Chap. V. p. 274; Anaxagoras, see Chap. VI. p. 312;
and for Anaximander, Chap. I. p. 69, _n._ 132.

Footnote 972:

Arist. _de Caelo_, Β, 13. 295 a 10, ταύτην γὰρ τὴν αἰτίαν (sc. τὴν
δίνησιν) πάντες λέγουσιν ἐκ τῶν ἐν τοῖς ὑγοῖς καὶ περὶ τὸν ἀέρα
συμβαινόντων· ἐν τούτοις γὰρ ἀεὶ φέρεται τὰ μείζω καὶ τὰ βαρύτερα πρὸς
τὸ μέσον τῆς δίνης.

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 communicated 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 doxography of Leukippos,[973] 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.[974] There is no question of “centrifugal force” at all, and the analogy of eddies in air and water is quite satisfactory.

Footnote 973:

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.

Footnote 974:

Cf. Lucr. v. 621 sqq.

[Sidenote: The earth and the heavenly bodies.]

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.[975] 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.[976] 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.[977] 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.[978] 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.[979]

Footnote 975:

Aet. iii. 3, 10, quoted above, p. 83, _n._ 168.

Footnote 976:

Aet. iii. 12, 1, Λεύκιππος παρεκπεσεῖν τὴν γῆν εἰς τὰ μεσημβρινὰ μέρη
διὰ τὴν ἐν τοῖς μεσημβρινοῖς ἀραιότητα, ἅτε δὴ πεπηγότων τῶν βορείων
διὰ τὸ κατεψῦχθαι τοῖς κρυμοῖς, τῶν δὲ ἀντιθέτων πεπυρωμένων.

Footnote 977:

Diog. ix. 33, εἶναι δὲ τὸν τοῦ ἡλίου κύκλον ἐξώτατον, τὸν δὲ τῆς
σελήνης προσγειότατον, <τοὺς δὲ> τῶν ἄλλων μεταξὺ τούτων.

Footnote 978:

From Diog., _loc. 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.

Footnote 979:

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 of
Demokritos (Βροντὴν ... ἐκ συγκρίματος ἀνωμάλου τὸ περιειληφὸς αὐτὸ
νέφος πρὸς τὴν κάτω φορὰν ἐκβιαζομένου, _ib._ 11). The explanation
given by Leukippos is derived from that of Anaximander, while
Demokritos is influenced by Anaxagoras. See Diels, 35 _Philol.-Vers._
97, 7.

[Sidenote: Perception.]

182. Aetios expressly attributes to Leukippos the doctrine that the objects of sense-perception exist “by law” and not by nature.[980] This must come from Theophrastos; for, as we have seen, all later writers quote Demokritos only. A further proof of the correctness of the statement is that we also find it attributed to Diogenes of Apollonia, who, as 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 “names,”[981] and Empedokles had also spoken of coming into being and passing away as only “names.”[982] It is not likely that Leukippos went much further than this. It would probably be wrong to credit him with Demokritos’s clear distinction between genuine and “bastard” knowledge, or that between what are now called the primary and secondary qualities of matter.[983] These distinctions imply a conscious epistemological theory, and all we are entitled to say is that the germs of this were already to be found in the writings of Leukippos and his predecessors. Of course, these do not make Leukippos a sceptic any more than Empedokles or Anaxagoras, whose remark on this subject (fr. 21_a_) Demokritos is said to have quoted with approval.[984]

Footnote 980:

Aet. iv. 9, 8, οἱ μὲν ἄλλοι φύσει τὰ αἰσθητα, Λεύκιππος δὲ Δημόκριτος
καὶ Ἀπολλώνιος νόμῳ. See Zeller, _Arch._ v. p. 444.

Footnote 981:

Chap. IV. p. 200, _n._ 443. The remarkable parallel quoted by Gomperz
(p. 321) from Galilei, to the effect that tastes, smells, and colours
_non sieno altro che puri nomi_ should, therefore, have been cited to
illustrate Parmenides rather than Demokritos.

Footnote 982:

See p. 240, fr. 8.

Footnote 983:

For these see Sext. _Math._ vii. 135 (R. P. 204).

Footnote 984:

Sext. vii. 140, “ὄψις γὰρ ἀδήλων τὰ φαινόμενα,” ὥς φησιν Ἀναξαγόρας,
ὃν ἐπὶ τούτῳ Δημόκριτος ἐπαινεῖ.

There appear to be sufficient grounds for ascribing the theory of perception by means of _simulacra_ or εἴδωλα, which played such a part in the systems of Demokritos and Epicurus, to Leukippos.[985] 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.

[Sidenote: Importance of Leukippos.]

183. We have seen incidentally that there is a wide 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 space. Parmenides had seen that very clearly (fr.2), and it was the Eleatic criticism which forced Leukippos to formulate his system as he did. Even Anaxagoras took account of Zeno’s arguments about divisibility (§ 128), but his system of qualitatively different “seeds” was lacking in that simplicity which has always been the chief attraction of atomism.

Footnote 985:

See Zeller, “Zu Leukippus” (_Arch._ xv. p. 138). The doctrine is
attributed to him in Aet. iv. 13, 1 (_Dox._ p. 403); and Alexander,
_de Sensu_, pp. 24, 14 and 56, 10, also mentions his name in connexion
with it. This must come from Theophrastos.