Aristotle (384-322 BC)
Aristotle
(384-322 BC), Greek philosopher and scientist, who shares with Plato and
Socrates the distinction of being the most famous of ancient philosophers.
Aristotle was born at
When Plato died in 347 BC,
Aristotle moved to Assos, a city in
Works
Aristotle, like Plato, made
regular use of the dialogue in his earliest years at the Academy, but lacking
Plato's imaginative gifts, he probably never found the
form congenial. Apart from a few fragments in the works of later writers, his
dialogues have been wholly lost. Aristotle also wrote some short technical
notes, such as a dictionary of philosophic terms and a summary of the doctrines
of Pythagoras. Of these, only a
few brief excerpts have survived. Still extant, however,
are Aristotle's lecture notes for carefully outlined courses treating almost
every branch of knowledge and art. The texts on which Aristotle's reputation
rests are largely based on these lecture notes, which were collected and arranged
by later editors.
Among the texts are treatises
on logic, called Organon (“instrument”), because they provide the means by
which positive knowledge is to be attained. His works on natural science
include Physics, which gives a vast amount of information on astronomy,
meteorology, plants, and animals. His writings on the nature,
scope, and properties of being, which Aristotle called First Philosophy (Prote
philosophia), were given the title Metaphysics in the first published edition
of his works (60? BC), because in that edition they
followed Physics. His treatment of the Prime Mover, or first cause, as
pure intellect, perfect in unity, immutable, and, as he said, “the thought of
thought,” is given in the Metaphysics. To his son Nicomachus he dedicated his
work on ethics, called the Nicomachean Ethics. Other essential works include
his Rhetoric, his Poetics
(which survives in incomplete form), and his Politics (also
incomplete).
Methods
Perhaps because of the
influence of his father's medical profession, Aristotle's philosophy laid its
principal stress on biology, in contrast to Plato's emphasis on mathematics.
Aristotle regarded the world as made up of individuals (substances) occurring
in fixed natural kinds (species). Each individual has its built-in specific
pattern of development and grows toward proper self-realization as a specimen
of its type.
Growth, purpose, and
direction are thus built into nature. Although science studies general kinds,
according to Aristotle, these kinds find their existence in particular
individuals. Science and philosophy must therefore balance, not simply choose
between, the claims of empiricism (observation and sense experience) and
formalism (rational deduction).
One of the most distinctive
of Aristotle's philosophic contributions was a new notion of causality. Each
thing or event, he thought, has more than one “reason” that helps to explain
what, why, and where it is. Earlier Greek thinkers had tended to assume that
only one sort of cause can be really explanatory; Aristotle proposed four. (The
word Aristotle uses, aition, “a responsible, explanatory factor” is not
synonymous with the word cause in its modern sense.)
These four causes are the
material cause, the matter out of which a thing is made; the efficient cause,
the source of motion, generation, or change; the formal cause, which is the
species, kind, or type; and the final cause, the goal, or full development, of
an individual, or the intended function of a construction or invention. Thus, a
young lion is made up of tissues and organs, its material cause; the efficient
cause is its parents, who generated it; the formal cause is its species, lion;
and its final cause is its built-in drive toward becoming a mature specimen. In
different contexts, while the causes are the same four, they apply
analogically. Thus, the material cause of a statue is the marble from which it
was carved; the efficient cause is the sculptor; the formal cause is the shape
the sculptor realized—Hermes, perhaps, or Aphrodite; and the final cause is its
function, to be a work of fine art.
In each context, Aristotle
insists that something can be better understood when its causes can be stated
in specific terms rather than in general terms. Thus, it is more informative to
know that a sculptor made the statue than to know that an artist made it; and
even more informative to know that Polycleitus chiseled it rather than simply
that a sculptor did so. Aristotle thought his causal pattern was the ideal key
for organizing knowledge. His lecture notes present impressive evidence of the
power of this scheme.
Doctrines
Some of the principal aspects
of Aristotle's thought can be seen in the following summary of his doctrines,
or theories.
Physics, or Natural Philosophy
In astronomy, Aristotle proposed
a finite, spherical universe, with the earth at its center. The central region
is made up of four elements: earth, air, fire, and water. In Aristotle's
physics, each of these four elements has a proper place, determined by its
relative heaviness, its “specific gravity.” Each moves naturally in a straight
line—earth down, fire up—toward its proper place, where it will be at rest.
Thus, terrestrial motion is always linear and always comes to a halt. The
heavens, however, move naturally and endlessly in a complex circular motion.
The heavens, therefore, must be made of a fifth, and different element, which
he called aither. A superior element, aither is incapable of any change other
than change of place in a circular movement. Aristotle's theory that linear
motion always takes place through a resisting medium is in fact valid for all
observable terrestrial motions. He also held that heavier bodies of a given
material fall faster than lighter ones when their shapes are the same, a
mistaken view that was accepted as fact until the Italian physicist and
astronomer Galileo conducted his experiment with weights
dropped from the Leaning Tower of Pisa.
Biology
In zoology, Aristotle
proposed a fixed set of natural kinds (“species”), each reproducing true to type.
An exception occurs, Aristotle thought, when some “very low” worms and flies
come from rotting fruit or manure by “spontaneous generation.” The typical life
cycles are epicycles: The same pattern repeats, but through a linear succession
of individuals. These processes are therefore intermediate between the
changeless circles of the heavens and the simple linear movements of the
terrestrial elements. The species form a scale from simple (worms and flies at
the bottom) to complex (human beings at the top), but evolution is not
possible.
Aristotelian Psychology
For Aristotle, psychology was
a study of the soul. Insisting that form (the essence, or unchanging
characteristic element in an object) and matter (the common undifferentiated
substratum of things) always exist together, Aristotle defined a soul as a
“kind of functioning of a body organized so that it can support vital
functions.” In considering the soul as essentially associated with the body, he
challenged the Pythagorean doctrine that the soul is a spiritual entity
imprisoned in the body. Aristotle's doctrine is a synthesis of the earlier
notion that the soul does not exist apart from the body and of the Platonic
notion of a soul as a separate, nonphysical entity. Whether any part of the human
soul is immortal, and, if so, whether its immortality is personal, are not
entirely clear in his treatise On the Soul. Through the functioning of the
soul, the moral and intellectual aspects of humanity are developed. Aristotle
argued that human insight in its highest form (nous poetikos, “active mind”) is
not reducible to a mechanical physical process. Such insight, however,
presupposes an individual “passive mind” that does not appear to transcend
physical nature. Aristotle clearly stated the relationship between human
insight and the senses in what has become a slogan of empiricism—the view that
knowledge is grounded in sense experience. “There is nothing in the intellect,”
he wrote, “that was not first in the senses.”
Ethics
It seemed to Aristotle that
the individual's freedom of choice made an absolutely accurate analysis of
human affairs impossible. “Practical science,” then, such as politics or
ethics, was called science only by courtesy and analogy. The inherent
limitations on practical science are made clear in Aristotle's concepts of
human nature and self-realization. Human nature certainly involves, for
everyone, a capacity for forming habits; but the habits that a particular
individual forms depend on that individual's culture and repeated personal
choices. All human beings want “happiness,” an active, engaged realization of
their innate capacities, but this goal can be achieved in a multiplicity of
ways.
Aristotle's Nicomachean
Ethics is an analysis of character and intelligence as they relate to
happiness. Aristotle distinguished two kinds of “virtue,” or human excellence: moral
and intellectual. Moral virtue is an expression of character, formed by habits
reflecting repeated choices. A moral virtue is always a mean between two less
desirable extremes. Courage, for example, is a mean between cowardice and
thoughtless
rashness; generosity, between extravagance and parsimony.
Intellectual virtues are not subject to this doctrine of the mean. Aristotle
argued for an elitist ethics: Full excellence can be realized only by the
mature male adult of the upper class, not by women, or children, or barbarians (non-Greeks),
or salaried “mechanics” (manual workers) for whom, indeed, Aristotle did not
want to allow voting rights. In politics, many forms of human association can
obviously be found; which one is suitable depends on circumstances, such as the
natural resources, cultural traditions, industry, and literacy of each
community. Aristotle did not regard politics as a study of ideal states in some
abstract form, but rather as an examination of the way in which ideals, laws,
customs, and property interrelate in actual cases. He thus approved the
contemporary institution of slavery but tempered his acceptance by insisting
that masters should not abuse their authority, since the interests of master
and slave are the same. The Lyceum library contained a collection of 158
constitutions of the Greek and other states. Aristotle himself wrote the
Constitution of Athens as part of the collection, and after being lost, this
description was rediscovered in a papyrus copy in 1890. Historians have found
the work of great value in reconstructing many phases of the history of
Logic
In logic, Aristotle developed
rules for chains of reasoning that would, if followed, never lead from true
premises to false conclusions (validity rules). In reasoning, the basic links
are syllogisms: pairs of propositions that, taken together, give a new
conclusion. For example, “All humans are mortal” and “All Greeks are humans”
yield the valid conclusion “All Greeks are mortal.” Science results from
constructing more complex systems of reasoning. In his logic, Aristotle
distinguished between dialectic and analytic. Dialectic, he held, only tests
opinions for their logical consistency; analytic works deductively from
principles resting on experience and precise observation. This is clearly an
intended break with Plato's Academy, where dialectic was supposed to be the
only proper method for science and philosophy alike.
Metaphysics
In his metaphysics, Aristotle
argued for the existence of a divine being, described as the Prime Mover, who
is responsible for the unity and purposefulness of nature. God is perfect and
therefore the aspiration of all things in the world, because all things desire
to share perfection. Other movers exist as well—the intelligent movers of the
planets and stars (Aristotle suggested that the number of these is “either 55
or 47”). The Prime Mover, or God, described by Aristotle is not very suitable
for religious purposes, as many later philosophers and theologians have
observed. Aristotle limited his “theology,” however, to what he believed
science requires and can establish.
Influence
Aristotle's works were lost
in the West after the decline of
Not only the discipline of
zoology, but also the world of learning as a whole, seems to amply justify
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