(hot-cold, wet-dry) accounts for change among the elements. Terrestrial changes are driven
ultimately by the northward and southward oscillation of the sun, and generation and
corruption will be continuous, the closest possible approximation to eternal being.
Meteorologica concerns the phenomena below the lowest sphere of the moon, and deduces
them from the material causes (the dry and the moist exhalations from the earth) and the
efficient cause (the sun). More specific causes include burning (comets, milky way), ejection
(lightning), condensation (dew, rain), reflection (rainbows). In absence of the final cause,
relative place above the earth (or below in the case of earthquakes and mineral formation) is
a fundamental ordering principle. Meteorologica 4 is a separate treatment of chemical trans-
formations (concoction, parboiling, etc.)
Aristotle’s biological works, the most extensive part of his natural writings, focus on
zoology. As he moves to more specific principles, his interpretation of matter and form is
adapted to living things. The principle of life is the soul, the form, or first actuality, of the
potentially living body, likened to the ability of the axe to cut (de Anima). Soul consists of a
series of ultimate functions: nutrition and reproduction, sensation and locomotion, intel-
lect. These are both the form and the final cause of a living thing. With the exception of
the intellect these functions cannot exist apart from the body (cf. Plato’s Pythagorean
soul). Each of the ultimate soul functions is characterized in relation to some external
object: the reception of food by digestion, the reception of the form of sensitive and
intelligible objects. The sense organs are affected and in turn affect the heart, the common
sensorium, which discriminates and unifies the sense perceptions. The heart is also the seat
of phantasia, the primary intentional faculty. The passive intellect contemplates its objects
through the illumination of the active intellect. The Short Natural Treatises (Parva Naturalia)
discusses some general life functions from other perspectives. Sense and Sensibilia discusses
what makes the objects of sense sensible. Other treatises concern memory and recollection,
dreams, and aging (all of which concern the physical principle, time). Of this same series
are the Movement of Animals and the Progression of Animals. The first is a discussion of the
general conditions of movement: the moved and moving parts of the body, desire, etc.; the
second is a specific treatment of the forms movement takes in various animal groups (flying,
crawling, swimming) and how many and of what form are the appendages (points of
motion).
The History of Animals is a sprawling collection of data in the Ionian tradition, probably
a collaboration with Theophrastos and other members of the Lyceum. It introduces a
new, empirical approach, appropriate here where data are available from extensive dissec-
tion and reports from fishermen, hunters and farmers. Since the physicist’s task is to study
both the matter and the form, the History is a description of the various parts of animals,
and their activities and functions. Aristotle isolates the universal nature of each animal
kind without reference to incidentals like the animals’ utility to man (in contrast to Theo-
phrastos’ parallel work on plants). The differences among animals are studied in accord-
ance with the basic principles of the Physics: privation and contrariety of properties.
Humans are studied first because of their familiarity, then the basic kinds of blooded
(viviparous quadrupeds, oviparous quadrupeds, birds, fishes, selachia and cetacea) and
bloodless animals (crustacea, testacea, insects) in their internal and external parts and their
behavior.
The History provides the facts for which the Parts of Animals gives the causes. The form,
the ultimate functions of the soul, provides the final cause, and the parts and tissues are
the material cause. These two causes, inherited from Plato’s Timaios, act together through
ARISTOTLE