II. THE CONCEPT OF MATTER IN
THE MIDDLE AGES
The medieval period was one of sometimes enlight-
ening elaborations of inherited theories of matter
rather than of significant innovations.
As philosophers became increasingly theological and
the pagan Empire increasingly Christian, the dominant
metaphysical paradigm was that of Plato. In fact one
finds in the Neo-Platonists, the Gnostics, and the
Manichaeans more radical statements of the hostility
of matter to perfection, intelligibility, and order, and
of its derivation from non-being than are to be found
in Plato himself. In one respect, however, patristic
thought can perhaps be said to be rather Aristotelian,
though historically the origins lie in Judaism. Jews,
Christians, and, later, Muslims were bound by biblical
revelation to a doctrine of creation ex nihilo, a creation
including that of matter and pronounced by God to
be good. This left a generous but still limited latitude
for variations. For one thing, if there was to be intel-
lectual accommodation for both God and the world,
organism must not be emphasized so far as to swallow
up the creature, nor the independence of parts em-
phasized, as it was in atomism, to the extent that it
would obviate the need of a Creator. Again, the Pla-
tonic characterization of the material world as “insub-
stantial appearance” might, if overstressed, undermine
the genuineness of the creation; on the other hand the
fully actual substances of atomism neither would need
to be nor could be created. Finally, though there was
no explicit theory of creation in Aristotle, his plurality
of substances would at least permit an independently
actual Creator and a dependently actual creation. Still,
however much this may have impressed later medieval
thinkers, the Patristics more immediately felt the ten-
sion of two inspirations: the Timaeus tradition of the
artist-God achieving levels of order with materials that
were not good, and the Judaic heritage in which all
hierarchy in the material world (like Aristotle's be-
tween celestial and terrestrial spheres) was thrown in
the shade by its universal creatureliness.
Alchemy, intrigued by the frequently dramatic
transformations of matter and dedicated to redeeming
it from its baser states, must probably be credited with
the most sustained program of empirical investigation
and with enough concrete discoveries so that both
Newton and Boyle paid it the compliment of serious
study. As to its theory alchemy represented a persisting
tradition of interpreting the physical and chemical
behavior of matter through biological, psychological,
and even theological models: matter could be “begot-
ten” in different species, induced to be more “noble,”
and “spiritualized” into its “essences.” But its principal
contributions to techniques and apparatus for fermen-
tation, sublimation, distillation, and the like were
matched by a multitude of scientifically advantageous
technological advances in such fields as engineering,
optics, metallurgy, and navigation, and historians have
had increasingly to recognize the extent and sophis-
tication of scientific inquiry within the universities
from the thirteenth century onwards.
Although Robert Grosseteste's brief treatise De luce
is of the mid-thirteenth century it illustrates impres-
sively the “light metaphysics” that was a special form
of the Neo-Platonic emanation-doctrine of the earlier
Middle Ages. The first material substance created (after
the “separate substances” which were pure forms) was
light. It enjoyed this priority because of, in one direc-
tion, its kinship with intelligibility and, in the other,
its tendency to uniform, instantaneous, and infinite
self-plurification. It thus engendered a three-dimen-
sional, spherical mass rarified at the periphery, con-
densed at the center, and within it the nine celestial
spheres took form, each inner ring being related to
the next outer as matter to form. The ninth, lowest,
and sub-lunar sphere was that of the four elements:
their differential weight behaviors sprang respectively
from the “self-assembling virtue” prevalent in earth
and water, and the “self-dispersing virtue” prevalent
in air and fire. Grosseteste found anticipations of this
cosmological system in pagan myth, speculating, for
example that “Cybele” was etymologically derived
from cubus and symbolized solidity. The theory also
had its quantitative (or numerological) aspect: light,
in which all other bodies were virtual, contained 4
basic constituents, and since the sum of its factors
(1, 2, 3, 4) was 10, “it is clear that 10 is the full number
of the universe.”
The advent in the twelfth and thirteenth centuries
of texts of Greek science, including predominantly the
physical, astronomical, biological, and metaphysical
texts of Aristotle, brought both a great upsurge in
scientific interests and the beginnings of a new scientific
orthodoxy. While sheer intellectual inertia no doubt
played its role in the authority that Aristotle came to
enjoy, the medievals were probably initially well ad-
vised to adopt a body of science far in advance of
anything with which they had been previously ac-
quainted, and thereafter the staying power of the the-
ory was to a considerable extent the result of its range
of use and success. But there also were developments
within, and departures from, the imported doctrines.
(1) The controversy over the plurality or unicity of
substantial forms which ranged Augustinian Platonists
like Saint Bonaventura against more radical Aristote-
lians like Aquinas involved questions of matter both
as principle of individuation and as proximate and pure
potentiality. Against the Thomistic doctrine that there
might be numerically distinct instances of things spe-
cifically identical in different “designated (ostensible)
matters,” the Platonists insisted that individuality was
a function of a unique intersection of formal properties.
Thomas' contention that with respect to man, for ex-
ample, “soul is not another form than that through
which three dimensions could be designated in the
thing” (De ente et essentia ii), combined with the
traditional Aristotelian teaching that substantial change
involves a reduction to “prime matter” or “pure po-
tentiality” seemed to deprive levels of form like “cor-
poreity,” “organism,” and “animality” of their func-
tions in nature. The dilemma in which the Aristotelians
found themselves was that if existing substances could
enter into a new substance (e.g., a child) without
modification, the new substance was only a mechanical
combination; but if there was a reduction of all incor-
porated substances to prime matter, it would seem that
one ought to be able to produce any given substance
from any given combination of proximate matters. To
meet this difficulty they developed, beyond anything
found explicitly in Aristotle, a theory of virtutes, or
powers. These powers bore close resemblance to the
substantial forms of the proximate matter prior to its
ingredience in the new substance; they nevertheless
represented some modifications by the new environ-
ment within the substance; and they were potentially
restorable to their original states on the dissolution of
the substance.
(2) There was also increasingly from the thirteenth
century on a tendency towards more atomistic con-
ceptions of matter. Augustine was typical of the early
Middle Ages in maintaining its infinite divisibility: the
diffuseness of matter thus stood at the opposite extreme
from the total unity of God. Aquinas sharpened the
Aristotelian distinction between the potentially infinite
divisibility of the “intellectual matter” of mathe-
maticals and the determinate quantities required in
actual physical substances, including the elements
(Physicorum lect. ix. 9-10). William of Ockham's res-
ervation of “absolute existence” to substance and qual-
ity alone of the traditional ten categories meant that
the view of nature as a network involving connective
quantities, relations, and acts was yielding to a view
of localized centers of formed matter. But in addition
to this very general evolution of medieval thought from
enthusiastic system towards critical, and even icono-
clastic, analysis, there was specifically a doctrine of
elementary minima being elaborated during the Ren-
aissance within the Aristotelian tradition by such
natural philosophers as J. C. Scaliger and Daniel Sen-
nert, so that the adoption of atomistic theories in the
seventeenth century was not exclusively a matter of
revival.
(3) Finally there seem to have been some anticipa-
tions during the latter Middle Ages of modern theories
of force and mass. Jean Buridan (ca. 1299-ca. 1358),
from whose rejection of Intelligences as movers of the
heavenly spheres Duhem dated the beginning of mod-
ern science (Etudes sur Léonard de Vinci [1955], III,
ix) helped to develop a theory of the preservation of
motion by an originally impressed impetus which acted
without diminution so long as it met no resistance. As
for mass, Jammer finds significant the use by Giles of
Rome, in his Theoremata de corpore Christi (1276), of
the phrase Quantitas materiae in a meaning exclusive
of both volume and weight. Prior to the conceptualiza-
tion of inertial mass by Kepler, natural philosophers
like Buridan, Albert of Saxony, Nicole Oresme, and
Richard Swineshead were identifying quantity of mat-
ter with a product of volume times density. In spite
of the greater specificity with which questions about
matter were being put, thanks to awakened interest,
suspicion of traditional answers, and improved tech-
niques, the late medievals had, of course, no way of
determining quantity of matter and density inde-
pendently.
