I. THE FOUR ELEMENTS
The soul was traditionally associated with blood,
breath, semen, the warmth
of life, and the persona.
Each of these retained significance as theorizing
de-
veloped. The most universal was the
conception of vital
warmth, which was regarded as one aspect of the
role
played by heat in the cosmos. Here the early cosmol-
ogists combined three traditional ideas: vital
warmth;
the seasonal powers of hot, cold, wet, and dry; and
the four
world-masses of fire, air, water, and earth.
Vital warmth was extended from
warm-blooded ani-
mals to all animals and even
to plants. It clearly meant
more than temperature, for pine wood (which is
not
hotter to touch than other timber) was thought to
contain more
heat and therefore to burn better. Hotter
plants have better fruit; hotter
animals are more intel-
ligent. Animal
droppings may still contain the warmth
of life, enabling them to generate
maggots. This is the
concept of heat as a stuff, not merely a quality
and
not necessarily perceptible, which survived into the
eighteenth-century theory of phlogiston. It was com-
mon ground among ancient scientists, even those who
did not consider
heat to be an element. The atomist
Democritus, for instance, who argued
that heat is
merely a sensation, nevertheless gave it an objective
basis by saying that it is the round atoms that feel
hot and that form the soul; that the heart contains the
fire of
life; that stags grow horns because their bellies
are hot and send the
nourishment upwards; that the
owl sees in the dark because she has fire in
her eyes.
These views are typical of the age.
As heat is necessary to life, so cold brings death:
it is not mere absence
of heat, but a stuff with its own
powers. Wet and dry also figure in early
theorizing,
more commonly than other powers, as being necessary
in
various forms of liquid and solid. These four were
assimilated to fire,
air, water, and earth. The two sets
do not exactly match, but Aristotle
eventually recon-
ciled them by a formula of
cross-pairing: fire is hot
plus dry, air is hot plus wet, and so on. He
held that
hot, cold, wet, and dry are the primitive qualities of
matter but cannot exist in isolation, while fire, air,
water, and earth are
the simplest separable elements,
capable of transformation into each other.
Some medical theorists at first opposed the concept
of four elements,
arguing that there are other equally
basic powers in the body, such as the
sweet, bitter,
salty, acid, astringent, insipid, and that the body con-
tains separate essential liquids (later
“humours” from
the Latin translation). After
controversy the humors
were agreed to be four—blood, black bile,
yellow bile,
phlegm—which were accommodated to Aristotle's ele-
ments by similar cross-pairing: blood is hot
plus wet
plus sweet, phlegm is cold plus wet plus salty.... Each
humor
was associated with a season and a human
temperament. This systematization
lasted through the
Middle Ages.
Heat always seemed the chief active force. Its char-
acteristic action was to concoct materials, to bring
them to fruition, to energize, sometimes to volatilize
or dissolve. Cold
caused condensing, coagulation, so-
lidifying. When Aristotle called hot and cold the chief
instruments
of nature, he was expressing a universal
view, whose details clearly
originated from kitchen and
garden. Water and earth were the materials
upon
which hot and cold worked; Aristotle analyzed them
into various
kinds of liquid and solid.
The importance of a fruitful balance among ele-
ments, a harmony of opposites, impressed the Greeks
perhaps more
than other peoples, and came from them
into medieval European thought. The
idea of symmetry
and proportionate blending dominated their medicine,
their art and architecture, their social and political
thinking. The
cosmologist Alcmaeon, who was also a
physician, made it his first cosmic
principle under the
political metaphor isonomia
(“equality of rights”).
When applied to mixtures of
materials, it led the way
from a qualitative assessment towards a
quantitative
chemistry. But the ancients did not go far in that
direction. Aristotle held that if the proportions of a
mixture were upset, one ingredient could master
(
kratein) the others. Wine and water can form a mix-
ture; but a single drop of wine, put into an
ocean,
would be overcome and would lose its nature entirely.
Both
concepts, proportion and mastery, are important
in his biology,
particularly in genetics.
