Dictionary of the History of Ideas Studies of Selected Pivotal Ideas |
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![]() | Dictionary of the History of Ideas | ![]() |
ATOMISM: ANTIQUITY TO THE
SEVENTEENTH CENTURY
The aim of this study is to examine in what way
the
different Greek and medieval conceptions of nature
have
contributed to paving the way for the scientific
theories of modern times.
Within this general frame-
work we shall pay
special attention to the classical
atomic theory in its different variants,
because the
development of this theory illustrates to what extent
modern science, with its underlying conception of
nature, can be traced to
the speculations of Greek
philosophy.
The very fact that the atomic theory has a long
history does not make it
easy to define its content in
such a way as to comprehend its different variations.
In its widest sense it may be defined, however, as the
theory
that nature is composed of relatively simple and
relatively unchangeable
minute particles, which are
too small to be directly observable. The
observable
changes in nature can be explained, however, by their
reduction to changes in the configuration of the parti-
cles. The observable multiplicity of the existing
forms
in nature must likewise be based upon differences of
forms and
of configuration of the particles.
Within this general atomistic conception a distinc-
tion can be made between atomism in the strict sense,
and other
forms. Atomism in the strict sense, pro-
pounded by Leucippus and Democritus (fifth century
B.C.), is the
doctrine that the particles, of which the
material things are composed, are
simple and un-
changeable in an absolute
sense (hence the name
“atoms,” which means
indivisible). Whatever may be
the changes in configuration of these atoms,
the atoms
themselves remain intrinsically unchanged. The ob-
servable differences in nature, however,
are not exclu-
sively based upon differences
in configuration of the
atoms. Another ground of difference is to be found
in
the atoms themselves. Although the atoms do not differ
qualitatively, they are supposed to have different sizes
and shapes, even
in an infinite multitude. Consequently,
the infinite variety of observable
things can be ex-
plained by these different
sizes and shapes and by the
different ways in which the atoms can be
combined.
As to the question of what causes the atoms to
combine and recombine,
Democritus points to motion
as a primitive property of atoms. This motion
itself
is not caused by an outside force; it is an inherent
property
of the atoms. Like the atoms themselves, their
motion is eternal and
incorruptible.
Other forms of Greek atomism differ from the atom-
ism of Democritus mainly in three points. First, they
do not
restrict the differences between the atoms to
purely quantitative ones, but
also accept differences
in quality. Anaxagoras (fifth century B.C.) assumed
even
as many qualitatively different atoms as there are
different
natural kinds of substances. As a rule, how-
ever, the more “liberal” forms of atomism accept
only
a limited number of types of primitive atoms. Their
qualitative
differences are usually based upon the
widespread doctrine of the four
elements: earth, water,
air, and fire (Empedocles, fifth century B.C.).
A second point of difference concerns the
indivisi-
bility
of the atoms. Whereas Democritus holds that this
indivisibility has
to be taken in a strict sense, other
forms of
“atomism” speak of an indivisibility only in
a
relative sense. The smallest particles of a certain
substance could be
divided, but then they change their
nature. Here again Anaxagoras has a
different opinion.
In his conception the particles could infinitely be
di-
its importance in the Middle Ages the most interesting
doctrine is that which found its origin in the circles
of Aristotle's commentators. Finally, the most general
characteristic which distinguishes Democritus' atomism
from other doctrines is probably its conception of
nature. Whatever forms may be found in nature, their
origin has to be sought exclusively in the inherent
properties of the atoms: their number, size, shape, and
their motion. Other doctrines assume, in one way or
another, some fundamental nonmaterial principle as
the source of the order in nature.
The best way to understand the specific features of
Democritus' atomism is
to examine the problems for
which he sought a solution. These were not the
kind
of problems in which modern scientific atomic theory
is engaged.
This is not to say that there is no connection
at all, for there is an
unmistakable historical connec-
tion, but the
intellectual climate of the fifth century
B.C. differed considerably from
ours. Not only are
modern scientific problems posed within the context
of already existing scientific theories and hypotheses,
but they also
presuppose an intellectual tradition. The
first Greek philosophers,
however, had to find their way
without such a tradition; their task was the
very crea-
tion of an intellectual climate in
which scientific the-
ories could be
formulated.
Shortly before Democritus, Parmenides and Hera-
clitus had already considerably contributed to the cre-
ation of such a climate. Parmenides (about
500 B.C.)
was greatly impressed by the cognitive power, pos-
sessed by the human intellect: only that
can exist which
can be understood (cf. Diels, frag. B. 3). Guided by
this principle, Parmenides, through subtle arguments,
came to the
conclusion that reality must be one and
immutable, despite the apparent
testimony of the
senses to the contrary. At first sight, Parmenides'
thesis
does not at all seem favorable for the rise of modern
science.
This science is based upon the careful obser-
vation of facts, and the empirical evidence of plurality
and
change in nature is indisputable. Nevertheless, a
closer consideration of
Parmenides' thesis about the
unity and immutability of reality reveals its
profound
meaning for physical science too. Without immutabil-
ity in nature, there would be no room at all for
scien-
tific
laws. Without unity in nature, there would be no
room for universal laws.
Nevertheless, the approach of Parmenides to under-
standing reality was too one-sided. It did not take the
testimony of the senses seriously enough. This same
testimony led his
contemporary Heraclitus to the as-
sertion
that everything is mutable (πάνγα
ρει) and
nothing remains.
Democritus' atomism has to be un-
derstood as
an attempt to combine the fundamental
thesis of Parmenides, prerequisite for any rational ex-
planation, with the reality of change and
multiplicity.
For this reason the atoms are unchangeable and quali-
tatively the same. The observable
multiplicity and
qualitative change can sufficiently be explained by
the
quantitative differences between the atoms and by their
motion,
which opens up the possibility of their combi-
nation and recombination. Why did Democritus think
his
retouching of Parmenides' thesis was justified? Jus-
tification lay in the fact that changes in
configuration
and quantitative difference are mathematically intel-
ligible. Thus he did not come into
conflict with Par-
menides' first principle:
“Only that can exist which can
be understood.”
Parmenides' great impact of Greek thought is shown
by the fact that his
considerations form the starting
point of practically all later Greek
conceptions of
nature, including those conceptions which greatly
differ from Democritus' atomism.
The main reason why later philosophers, such as
Plato and Aristotle,
rejected Democritus' solution of
the problems of change and multiplicity
was not on
account of the general idea of atoms, but because of
the
one-sidedness of the atomic theory, considered as
a universal theory. For
Democritus the theory was not
merely intended as an explanation of natural
phenom-
ena, such as evaporation, or the
existence of different
states of aggregation. Its aim was to give an
ultimate
explanation of change as change, including also those
changes
occurring in man's mental activity. For this
reason Democritus assumed
atoms of a special form
and shape for the composition of the soul. Because
they
are fine and round, the atoms of the soul can penetrate
the whole
body, move it, and thus cause its vital func-
tions. Whatever may be the fruitfulness of the atomistic
approach to
the explanation of natural phenomena, the
atomic theory of Democritus was
not judged on its
merits as a merely physical theory, for such a
theory
did not yet exist. The theory was judged on its merits
as a
universal explanation of the whole of reality. As
such it was rejected. It
was too materialistic, in reduc-
ing all
qualities and feelings to quantities of atoms, and
their configuration.
Only gradually did man learn to
distinguish methodically the different
problems which
are interwoven in Democritus' system. In Greek
thought
philosophy and science still formed a unity.
This holds true also of other
forms of atomism, which
can be distinguished from atomism in the strict
sense.
Plato, for example, in the Timaeus propounded an
atomic theory of his own, but only as a minor aspect
of a much broader
idealistic conception of nature. In
order to understand this conception we
must return
again to the sharply contrasting views of Parmenides
and
Heraclitus. For Parmenides reality was immutable
accepts both views, but with respect to different reali-
ties, the unchangeable world of ideas and the changing
world of sense perception, respectively. The latter
world is a shadow of the first, or its imperfect embodi-
ment. Consequently, true knowledge is not directed
towards the imperfect world of change, but towards
the real unchangeable world. On account of the im-
perfection and continuous change of the natural things
natural science could only be an imperfect science. A
further consequence of Plato's conception of the two
worlds is that the principle of order in nature was not
to be found in nature itself, but in the world from
which it is derived. This also explains the great value
Plato assigned to mathematics. For the object of math-
ematics is not the observable realization of a circle
or a triangle, but their ideas or essences in their un-
observable, logical purity.
A few words remain to be said about Plato's atomic
theory. He accepts the
elements which Empedocles
has proposed on empirical grounds: fire, air,
water, and
earth. In accordance with his views of the importance
of
mathematics, Plato tries to characterize the atoms
of these elements by
means of their mathematical form.
Fire has the form of a tetrahedron, air
of an octahe-
dron, water of an icosahedron,
and earth of a cube.
The concrete characterization is, of course,
arbitrary,
but the idea of connecting physical properties with
mathematical structures is in itself extremely fruitful.
Yet no physical
science could arise from this general
idea. The distance between the
observable phenomena
and the hypothetical structure was too great.
Aristotle approached the problems of natural science
much more empirically
than either Democritus or
Plato. He could not accept the viewpoint of Democ-
ritus that all observable change is only
accidental, and
differed with Plato mainly on the theory of knowledge.
For Aristotle experience was the sole fount of human
knowledge, including
the knowledge of abstract pure
concepts. As a consequence, he rejected the
distinction
between the unchangeable world of ideas and the
observable
world of change. Having safeguarded the
reality of the sensible world,
Aristotle faced the diffi-
culties of
Parmenides. How is real change possible?
Atomism certainly opened up the
possibility of ex-
plaining accidental
changes, in which things did not
change their nature, but it could not
explain changes,
in which things lost their nature. Nor did it account
for the existing variety of natural things. It could ac-
count for the accidental variety, but not for the fact
that nature showed a fixed order in the variety of
things, an order which
remained constant through the
transitory existence of phenomena. Thus the
first task
imposed upon Aristotle was a critical reexamination
of
Parmenides' thesis.
In order to be intelligible, the possibility of change
presupposes a certain
fundamental complexity rather
than simplicity in material things. Otherwise
it is not
possible to account for both aspects that are present
in
change: the aspect of certain permanence, and the
aspect of something that
is really new. To a certain
extent Democritus followed the same line of
thought.
Democritus, however, “substantialized” the
permanent
aspect, for the atoms were things, which
existed as
such. Thus the possibility of change was narrowed
down to
accidental changes of configuration. In the
eyes of Aristotle, the
permanent aspect could not be
a thing, but only a principle, i.e.,
something that does
not exist in itself, but only as a component of a
whole.
Aristotle calls it matter (hylē). Matter is not a substance,
but only the capacity
to receive “forms.” Since matter
is not itself a
substance, even the most radical changes
are possible. For existing things
are composed of matter
and form, i.e., matter that has received a form.
Things
can change, because one form can supersede another.
The most
radical changes are those in which things
receive a new substantial form.
In this case their nature
changes.
The way in which Aristotle discusses the possibility
of change makes it
clear that he has quite another
conception of nature than that of
Democritus' atomism.
With Aristotle nature refers to something
fundamental
in material things, which is both the source and the
end
of their growth, their movements, and their
changes. “The
primary and proper meaning of 'na-
ture' is the
essence of things which have in themselves
(qua
themselves) a principle of motion” (Metaphysics,
Book IV). Because each thing acts according to its
nature, i.e., according to its natural form, each thing
strives for its
proper end, i.e., its place in the whole
of the cosmos. Thus there is a
kind of “built-in” natural
order, based upon a
natural series of final causes.
In these conceptions of Aristotle there is, of course,
no place for
unchangeable atoms. This does not mean,
however, that Aristotle had no
thought of minute par-
ticles. Although he did
not propound a corpuscular
theory of his own, we find a few remarks that
could
have been the starting point for such a theory. The
remarks form
part of Aristotle's criticism of Anax-
agoras' theory about the infinite divisibility of material
things.
Somewhere there must be a limit to divisibility,
which limit is determined
by the specific nature of the
things in question. It was left to
Aristotle's Hellenistic,
Arabian, and medieval commentators to develop
the
casual remarks of their master into the minima
natu-
ralia theory, stating
that each kind of substance has
combined the empirical approach of Aristotle with the
more rational approach of Democritus. Thus they pre-
pared the way for the scientific atomic theory of mod-
ern times.
Before we discuss, however, the gradual shift of
emphasis from a philosophic
to a scientific atomic
theory, we must first turn our attention to an
aspect
of the Greek ideas of “nature,” which played
an im-
portant role namely, the ethical
dimension of their
concept of nature. It is interesting to note that the
use
of the term “natural law” arose first in the
ethical
realm. The reason may have been that the phenomena
of nature
at first impressed man as much more unpre-
dictable than human behavior, which was subject to
fixed laws.
The Greeks themselves did not even use
the term “natural
law” in the sense it has nowadays
in physical science: the
latter sense dates from modern
times. This does not mean, as we have seen,
that the
Greeks were not familiar with the idea of a rational
order in
nature. On the contrary, this idea was central
to their thought, but they
did not express it in terms
of laws. Even with respect to the ethical
sense, the
coupling of nature and law into a single expression does
not seem to have occurred before the last phase of
Greek philosophy as
represented by Stoicism.
By speaking of “natural law” the Stoics revived to
a
certain extent the pre-rationalistic conception of
mythological thought, in
which hardly any distinction
was made between the orders of nature, of
culture,
and of ethics. The difference was, however, that the
Stoics
were convinced of the rationality of the all-
embracing order of nature. Because nature is perme-
ated with rationality, and rationality constitutes
the
nature of man, the Stoic philosophers could return to
the
identification of the natural and the ethical order,
without losing sight
of the special position which man
occupies in the natural order. For
precisely the reflec-
tion on this position
has marked the transition from
the mythological to the rational phase in
Greek
thought. By his reason (ratio) man could know
his own
place in the natural order, and by his free will he could
live
in accordance with the ethical obligations, which
followed from his own
place in this order. It is, there-
fore, no
coincidence that long ago the term “nature”
also
acquired the meaning of “essence.” The study of
the
order of natural things and the place of man in
it revealed both the
essence of natural things and that
of man.
It is not easy to summarize in a few words the
general characteristics of
the Greek conception of
nature. The great diversity of opinion among
Greek
philosophers makes it even impossible to speak of the
Greek conception. Yet the ethical connotation, which
the term
“nature” could acquire, indicates a certain
common
conviction with almost all Greek philoso-
phers, namely, that the order of nature is an order
which man cannot
change and which he has to accept
as it is. Within the order there was a
certain room
for human intervention, but the possibilities of this
intervention did not apply to nature as a whole, but
only to those aspects
of it which invited man, as it
were, to utilize them. The room in nature
for human
culture confirmed rather than weakened the idea of
the order
of nature.
Closely connected with the conception of nature as
an unchangeable order,
which man has to respect both
in his technology and in his ethics, was the
conviction
that the order of nature was something
“supernatural.”
It should be noted, however, that
this last conviction
was less general than the first.
In the Christian era the Greek conceptions of nature
were taken over, albeit
with an important correction.
The order of nature became a created order. Christian
thought broke with the
identification of the natural
and the supernatural, and with the
identification of the
natural and the ethical order. The transcendent
Creator
as the origin of nature and of man made it possible
to place
man apart from nature, even though their
common origin was maintained. The
ethical concept,
“natural law,” could be preserved,
but it now had a
different sense, because man's relationship to the Crea-
tor differs fundamentally from his relation
to nature.
Both nature and man are subjected to the divine law,
but
not on the same level. Man's freedom with respect
to nature was, in
principle, safeguarded; nature was
at his disposal. To what extent man
could “cultivate”
nature was, however, not clear. Man
had still to find
out.
As long as natural science seemed to be no more
than a rational affair, the
conception of nature as an
order which man could understand but not
change
remained predominant. Even after the Middle Ages
when
mathematical rationality superseded philo-
sophical rationality, this predominance was not seri-
ously affected. The new rationality of science
changed
the idea of the order of nature insofar as this order
became
the order of a mechanism. It became the con-
struction of a chief engineer, but it still remained an
order,
which could not be altered by man. He simply
seemed to lack the necessary
power. Only after it
became clear that in order to reach its rational
end
science had to use experimental means, could a new
conception of
nature appear. The laws of nature (in
the scientific sense) were not only
the signs of the
rationality of nature, but also the means for the manip-
supernatural and normative character. Through an
apparently fixed order of nature man saw an unlimited
field of possibilities, based upon the fundamental forces
of nature.
In the process that led to this view of nature, the
development of the
atomistic conceptions into an
experimental scientific theory played an
important
role. How did this development take place? For the
answer to
this question let us return to the Greek
atomic conceptions and follow
their development
through the centuries until the seventeenth century.
As
we have pointed out, there could not have been a
straightforward
development from the Greek atomic
theories to the scientific atomic
theories of modern
times. The main reason why this was impossible was
not that the Greek theories were, first of all,
philo-
sophical
theories, propounded to explain the possibility
of change in general.
This was, of course, a reason,
but there were nevertheless enough physical
aspects
in the atomistic doctrines which could function as the
beginning of a fruitful physical theory. The main diffi-
culty was that there was too great a gap between
the
observable phenomena and the theories in question,
even with
respect to their physical aspects. Accord-
ingly, it was not the atomic theory which was destined
to be the
first fruitful physical theory. This had to be
a theory in which the
observable phenomena were
much more directly suited to be fitted in a mathe-
matical model. It is, therefore, not
accidental that the
first fruitful general physical theory, namely
mechanics,
was of astronomical origin. Only after a general theory
of
mechanics was developed, which could be applied
to the hypothetical atoms,
was the time ripe for a
physical atomic theory.
With respect to a chemical atomic theory, the situa-
tion was different. Of course, this
theory had to wait
also until more general theories were developed,
but
typical corpuscular considerations could play a part
in the coming
into existence of these theories. It was
easier to characterize the
hypothetical atoms by their
chemical than by their physical properties. It
is obvious
that of the two important Greek corpuscular schools
of
thought, the atomism of Democritus and the minima
doctrine of the
commentators of Aristotle, the latter,
with its specific minima for each
kind of substance,
offered more possibilities for chemical
considerations.
The interesting point is that one of the main aspects
of the development of the minima doctrine lies pre-
cisely in a gradual development from a more philo-
sophical to a more chemical theory. Atomism does
not
show such a development. This is mainly due to the
fact that its
spiritual father Democritus had already
elaborated a more or less complete
doctrine, and that
it had only a few adherents between the fifth century
B.C. and
the seventeenth century; the most important
are Epicurus and the Latin poet
Lucretius Carus.
Epicurus introduced the idea of a chance swerve
(clinamen) of the atoms, which he and Lucretius
thought would make
intelligible new qualities and free
will. What atomism needed for its
development was,
above all, the connection with observable chemical
phenomena. And for such a development it was less
suited than the minima
theory. When atomism came
to occupy again a central position in the
seventeenth
century, it could profit from the development the
minima
theory meanwhile had made. What were the
main stages in this development?
To Aristotle himself the minima did not mean much
more than a theoretical
limit to divisibility; they were
potentialities rather than actualities.
Nothing indicates
that he attributed to the minima a certain measure
of
independent existence. As early as the Greek commen-
tators of Aristotle—Alexander of Aphrodisias
(second
century A.D.), Themistius (fourth century), and John
Philoponus (sixth century)—we find an important de-
velopment. In their thought the smallest
particles are
more than just potentialities, the commentators speak
of
the elachista, the Greek equivalent of minima, as
if
they actually existed. Furthermore, in reading these
commentators we get
the impression that they used
the term elachista in
a special, technical sense. Just
as for Democritus the term atomos does not mean
exclusively indivisible, but is also a technical term for
smallest particles,
so also something similar seems to
be the case with the word elachista. Each specific
substance has its own elachista.
Averroës (1126-98), the most important Arabian
commentator on
Aristotle, followed up this line of
thought. With him we find the
suggestion that the
elachista or minima play an important role during
chemical reactions. His Latin followers elaborated this
point. They do not
leave us in doubt that they attrib-
uted to
the minima not only an independent existence,
but also a certain function
in several physical and
chemical reactions. In their opinion the minima
were
the actual building stones of reality. Consequently, the
increase
or decrease in quantity of a substance amounts
to the addition or
subtraction of a certain number of
minima. Agostino Nifo (1473-1538)
assures us that a
chemical reaction takes place among the minima.
When
elements react upon each other they are divided
into minima.
The next step was now to examine how the proper-
ties of the minima, responsible for chemical and physi-
cal reactions, could be connected with the specific
observable properties of different substances. The first
attempt to do so
was, of course, not very spectacular,
coming into existence of chemical and physical the-
ories. According to J. C. Scaliger (1484-1558), some
properties of matter, such as fineness and coarseness,
depend on the properties of the minima themselves,
while others depend on the manner in which they are
joined. Rain, snow, and hail are all of the same coarse-
ness, because they are composed of the same minima,
but their density is different, because the minima of
these three substances are at a smaller or a greater
distance from one another. Scaliger knew not only
minima of elements, but also of compounds, although
he does not mention the latter as systematically as the
former. As to the chemical reaction, Scaliger is not
satisfied with the Aristotelian definition: the union of
the reagents, because the role of the minima is not
mentioned. He is not satisfied with Democritus either,
because Democritus' atoms could not really form a new
unity. Hence Scaliger's definition: chemical composi-
tion is the motion of the minima towards mutual con-
tact so that union is effected. As a follower of Aristotle,
Scaliger is convinced that for a true chemical compo-
sition a new substantial form is required.
The interesting point with such men as Scaliger and
Nifo is that on the one
hand they develop their ideas
within the conceptual framework of
Aristotle's philos-
ophy, whereas on the
other hand they transcend it.
Unlike certain Aristotelian circles, as those
of the
Thomists and Scotists, who limited themselves to the
discussion
of the minima and of chemical composition
merely with philosophical
concepts such as actual,
potential, form, etc., the Averroists make efforts
to
express in a more scientific way the relation between
the forms of
the elements and the form of the com-
pound.
Without abandoning the Aristotelian unity of
form in the compound, they
transform this concept
in the direction of what we may call the concept
of
“structure.” Thus they paved the way for a
new
framework of concepts, in which scientific theories
could be
formulated.
In the seventeenth century the creation of this new
conceptual framework
made great progress. This can
be shown from the fact that the philosophical
differ-
ences between the corpuscular
systems were soon
pushed into the background, while the more
scientific
aspects that were held in common came to the fore-
ground. Daniel Sennert (1572-1657) offers
a clear ex-
ample of this tendency. Basically,
his corpuscular the-
ory was derived from the
minima doctrine, but it also
contained typical ideas of Democritus'
atomism, that
in Sennert's days came to occupy a central position.
Sennert was, however, interested mainly in a chemical
theory, not in
philosophical disputes. He was of the
opinion that, from a chemical point
of view, atomism
and minima theory amount to the same thing. In order
to
maintain this opinion, Sennert had to revise the
atomistic doctrine. As a
chemist, Sennert was con-
vinced that
elementary atoms differ qualitatively and
that a clear distinction should
be made between ele-
mentary atoms and atoms
of compounds (prima mista).
Modern chemistry
followed Sennert in this respect. It
shows how important the minima
doctrine has been.
Does this mean that the revival of atomism in the
strict sense did not have
any real effect? The contrary
is true. The real significance of this
revival must, how-
ever, not be sought in the
revival of the general idea
of reducing the observable phenomena to changes
in
the configuration of atoms, but in the inspiring convic-
tion that nature formed a unity, which
quantitatively
could be analyzed. This fundamental idea remained
alive
in modern science, even when at first the number
of qualitatively different
elementary atoms had to be
increased from four to more than ninety. Whereas
the
minima doctrine (and later on the chemical atomic
theory) accepted
the existence of qualitatively different
elementary atoms as an irreducible
fact, atomism did
not accept such an irreducibility. Whatever may be
the differences of the elementary atoms, these have
to be reduced to the
fundamental properties of all
matter. This idea has been proved successful
when the
structure of the atoms themselves became an object
of
scientific research. And it is still vivid in our times
when the number of
sub-atomic elementary particles
has increased tremendously. Science is
again looking
for unity in this diversity.
BIBLIOGRAPHY
R. G. Collingwood, The Idea of Nature, 2nd ed.
(New
York, 1960). E
. J. Dijksterhuis, The
Mechanization of the
World Picture (Oxford, 1960). R. W.
Hepburn, “Philosophical
Ideas of Nature,” in The Encyclopedia of Philosophy (New
York, 1967),
V, 454-58. F. A. Lange, Geschichte des Materi-
alismus und Kritik seiner
Bedeutung in der Gegenwart
(Iserlohn and Leipzig, 1866);
trans. E
. C. Thomas as History
of Materialism
(reprint, New York, 1950). K. Lasswitz,
Geschichte der Atomistik vom Mittelalter bis
Newton, 2 vols.,
2nd ed. (Leipzig, 1926). A. G. M. van
Melsen, From Atomos
to Atom, the History of the
Concept Atom, 2nd. ed. (New
York, 1960); idem, Physical Science and Ethics, a Reflection
on the
Relationship between Nature and Morality (Pitts-
burgh, 1967). C. J. de Vogel, Theoria, studies over de griekse
wijsbegeerte
(“Studies Concerning Greek Philosophy”)
(Assen,
1967). L. L. Whyte, Essay on Atomism: From Democ-
ritus to 1960 (London,
1961).
A. G. M. VAN MELSEN
[See also Atomism in the Seventeenth Century; Causation;Epicureanism; Law, Natural; Matter; Nature; Platonism;
Rationality; Stoicism.]
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