ARISTOTLS
716
ARISTOTLE
ity. Ex nihiln nihil jit. This is the principle of de-
velopment in Aristotle's philosophy which is so much
commented on in relation to the modern notion of
evolution. Mere potentiality, without any actuality
or realization — what is called materia prima — no-
where exists by itself, though it enters into the com-
IX)sition of all things except the Supreme Cause. It
is at one pole of reality. He is at the other. Both
are real. Materia prima possesses ■what may be
called the most attenuated reality, since it is pure
indeterminateness; God po.ssesses the highest ami
most complete reality, since He is in the highest
grade of deterniinateness. To prove that there is
a Supreme Cause is one of the tasks of metaphysics,
the Theologic Science. And this Aristotle under-
takes to do in several portions of his work on First
Philosophy. In the "Physics" he adopts and im-
proves on Socrates's teleological argument, the major
premise of which is, " Whatever exists for a useful
purpose must be the work of an intelligence". In
the same treatise, he argues that, although motion is
eternal, there cannot be an infinite series of movers
and of things moved, that, therefore, there must be
one, the first in the series, which is unmoved, t4 rpw-
Tor Kimvv anlvriTov — primum movens immobile. In the
" Metaphj'sics " he takes the stand that the actual
is of its nature antecedent to the potential, that,
consequently, before all matter, and all composition
of matter and form, of potentiality and actuality,
there must have existed a Being Who is pure actu-
ality, and Whose life is self-contemplative thought
(fiTjcris voijfffws). The Supreme Being imparted
movement to the imiverse by moving the First
Heaven; the movement, however, emanated from
the First Cause as desirable; in other words, the
p'lrst Heaven, attracted by the desirability of the
Supreme Being " as the soul is attracted by beauty",
was set in motion, and imparted its motion to the
lower spheres and thus, ultimately, to our terrestrial
world. According to tjiis theory, God never leaves
the eternal repose in which His blessedness consists.
AVill and intellect are incompatible with the eternal
unchangeableness of His being. Since matter, mo-
tion, and time are eternal, the world is eternal. Yet,
it is caused. The manner in which the world origi-
nated is not defined in .Aristotle's philosophy. It
seems hazardous to say that he taught the doctrine
of Creation. This much, however, may safely be
said: He lays down principles which, if carried to
their logical conclusion, woukl lead to the doctrine
that the world was made out of nothing.
(2) Physics. — Physics has for its object the study of "being intrinsically endowed with motion", in other words, the study of nature. For nature differs from art in this: that nature is essentially self- determinant from within, while art remains exterior to the products of art. In its self-determination, that is to say in its processes, nature follows an in- telligent and intelligible form, " Nature is always Btriving for the best". Movement is a mode of being, namely, the condition of a potential being actualizing itself. There are three kinds of movement, quanti- tive (increase and decrease), qualitative (alteration), and spatial (locomotion). Space is neitlier matter nor form, but the "first and unmoved limit of the containing, as against the contained". Time is the measure of the succession of motion. In his treat- ment of the notions of motion, space, and time, .Aris- totle refutes the I'.leatic doctrine that real motion, real space, and real siiccession imply contradictions. Following ICnipcdocU's .Aristotle, al.so, teaches that all terrestrial Ixjilics are coini)o.sed of four elements or ra<lical princi|ilcs, namely: fire, air, earth, and water. These elements determine not only the nat- ural warmtli or moisture of bodies, but also their natural motion, upward or downward, according to the prci«inilerance of air or earth. Celestial bodies
are not constituted by the four elements but by
ether, the natural motion of which is circular. The
Earth is the centre of the cosmic system; it is a .spheri-
cal, stationary body, and around it revolve the
spheres in which are fixed the planets. The First
Heaven, which plays so important a part in Aris-
totle's general cosmogonic system, is the heaven of
the fixed stars. It surrounds all the other spheres,
and, being endowed with intelligence, it turned
toward the Deity, drawn, as it were, by His Desira-
bility, and it thus imparted to all the other heavenly
bodies the circular motion which is natural to them.
These doctrines, as well as the general concept of
nature as dominated by design or purpose, came to
be taken for granted in every pliilosophy of nature,
down to the time of Newton and Galileo, and the
birth of modern physical science.
Psychology in Aristotle's philosophy is treated as a branch of physical science. It has for its object the study of the soul, that is to say, of the principle of life. Life is the power of self-movement, or of move- ment from within. Plants and animals, since they are endowed with the power of adaptation, have souls, and the human soul is peculiar only in this, that to the vegetative and .sensitive faculties, which characterize plant-life and animal life respectively, it adds the rational faculty — the power of acquiring universal and intellectual knowledge. It must there- fore be borne in mind that when Aristotle speaks of the soul he does not mean merely the principle of thought; he means the principle of life. The soul he defines as the form, actualization, or realization, of the body, "the first entelechy of the organized body possessing the power of life". It is not a .sub- stance distinct from the body, as Plato taught, but a co-substantial principle with the body, both being united to form the composite substance, man. The faculties or powers of the soul are five-fold, nutri- tive, sensitive, appetitive, locomotive, and rational. Sensation is defined as the faculty "by which we receive the forms of sensible things without the mat- ter, as the wax receives the figure of the seal without the metal of which the seal is composed". It is "a movement of the soul", the "form without the matter" being the stimulus which calls forth that movement. The tuttos, as that form is called, while it is analogous to the "effluxes" about which the Atomists spoke, is not like the efflux, a diminished object, but a mode of motion, mediating between the object and the faculty. Aristotle distinguishes between the five external senses and the internal senses, of which the most important are the Cen- tral sense and the Imagination. Intellect {mii) differs from the senses in that it is concerned with the abstract and universal, while they are concerned with the concrete and particular. The natural en- dowment of intellect is not actual knowledge, but merely the power of acquiring knowledge. The mind "is in the beginning without ideas, it is like a smooth tablet on which nothing is written". All our knowledge, therefore, is acquired by a process of elaboration or dcvelo]>nient of .sense-knowledge. In this process the intcllccl exhibits a two-fold pha.se, an active and a pas.sive. Hence it is customary to speak of the Active and Passive Intellect, tliimgh it is by no means clear what Aristotle meant by these concepts. The corruption of the text in some of the most critical passages of the work "On the Soul", the mixture of Stoic panthei.sm, in the explanation of the earlier commentators, not to speak of the later addition of extraneous elements on the part of the Arabian, Schola,stic, and modern transcendentalist expounders of the text, have rendered it impossible to say precisely what meaning to attach to the terms Active and Passive Intellect. It is enough to re- mark here that (1) according to the Scliolastics, Aristotle understood both Active and Passive In-
