The Teleology of Nature
Teleology is the study of the ends or purposes that things
serve, and Aristotle’s emphasis on teleology has repercussions throughout
his philosophy. Aristotle believed that the best way to understand
why things are the way they are is to understand what purpose they
were designed to serve. For example, we can dissect an animal to
see how its anatomical organs look and what they’re made of, but
we only understand each organ when we perceive what it’s supposed
to do. Aristotle’s emphasis on teleology implies that there is a
reason for everything. Just as Aristotle sees purpose in anatomical
and biological systems, he sees human life as organized and directed
toward a final end as well. Because we are essentially rational,
Aristotle argues that rationality is our final cause and that our
highest aim is to fulfill our rationality. This argument has a deep
impact both on Aristotle’s ethics and on his politics. The good
life, for which all our virtue and wisdom prepares us, consists
primarily of rational contemplation, and the purpose of the city-state
is to arrange matters in such a way as to maximize the opportunities
for its citizens to pursue this good life.
The Primacy of Substance
The term substance designates those things
that are most fundamental to existence. However, since there is
no clear or definite answer as to what those things are, substance is
effectively a metaphysical placeholder, a word that refers to a
problem rather than a definable thing. Aristotle points out that
some things do seem to be more fundamental than others. For example,
colors can only exist if there are physical objects that are colored,
though it seems conceivable that physical objects could potentially
exist in a world devoid of color. If there is a hierarchy to being,
such that some things are more fundamental than others, there must
be a most fundamental thing on which everything else depends. Aristotle
thinks that he can approach this most fundamental thing by examining
definition. Properly speaking, a definition should list just those
items without which the thing defined could not exist as it is.
For instance, the definition of a toe should mention a foot, because
without feet, toes could not exist. Since we cannot define toes
without making mention of feet, we can infer that feet are more
fundamental than toes. A substance, then, is something whose definition
does not rely on the existence of other things besides it.
Aristotle’s insistence on the primacy of substance reflects
his view that there is no single category of being. We can talk
about existence in connection with all sorts of things. Colors exist,
ideas exist, places exist, times exist, movements exist, and so
on. Part of Aristotle’s insight is that these things do not all
exist in the same way. That is, there is not some one thing called
“existence” in which colors and places partake in markedly different
ways. Rather, there are different categories of existence that apply
to different categories of things. Colors and places have two entirely
different kinds of existences. However, if different sorts of things
exist in different ways, how is it that there seems to be a single
cosmos in which color, place, time, and all the rest, seem to exist
together? The fact that color and substance have two different kinds
of existence does not prevent substances from being colored. For
the cosmos to be unified, there must be a base unit of existence
on which all other kinds of existence depend. Aristotle’s argument
for the primacy of substance, then, is his way of saying that it
is substance, and not time or location, that binds the cosmos together.
The Rejection of Plato’s Theory of Forms
By rejecting Plato’s Theory of Forms, Aristotle clears
the way for his empirical approach, which emphasizes observation
first and abstract reasoning second. Aristotle received his philosophical
education at Plato’s Academy, so it is natural that he would feel
obliged to justify at length why he departs from the doctrines of
his teacher. He provides detailed arguments against many of Plato’s
doctrines in almost all of his major works, focusing in particular
on the Theory of Forms. In Aristotle’s view, this theory is essentially
an assertion of the superiority of universals over particulars.
Plato argues that particular instances of, say, beauty or justice
exist only because they participate in the universal Form of Beauty
or Justice. On the contrary, Aristotle argues that universal concepts
of beauty and justice derive from the instances of beauty and justice
in this world. We only arrive at a conception of beauty by observing
particular instances of beauty, and the universal quality of beauty
has no existence beyond this conception that we build from particular instances.
By saying that the particulars come first and the universals come
after, Aristotle places emphasis on the importance of observing
the details of this world, which stands as one of the important
moments in the development of the scientific method.
Biology As a Paradigm
Aristotle’s methods in biology reveal a great deal about
his general methods in philosophy. He was the son of a doctor, and
his work shows a particular aptitude for biology. We might contrast
this fact with Plato’s aptitude for mathematics. Throughout Plato’s
work, we see a continual reference to the forms of reasoning involved
in mathematics as the paradigmatic example of what reasoning ought to
be. By contrast, we find Aristotle applying the lessons he draws from
his biological studies to philosophical questions far removed from
biology. Two pertinent examples are Aristotle’s emphases on teleology
and classification. Aristotle finds it useful when studying living
organisms always to ask what function an organ or a process serves,
and from this practical method he infers in general that all things
serve a purpose and that we can best understand the workings of
things by asking what ends they serve. Similarly, Aristotle develops
an ingenious system of classifying the various kinds of living organisms
according to species and genus, among other things, and proceeds
to find systems for classifying everything from the forms of poetry
to the categories of being. Most important, perhaps, is that Aristotle
draws from his biological research a keen eye for detail and an
emphasis on observation as the key to knowledge.
The Vagueness of the Practical Sciences
Aristotle rarely sets down hard and fast rules in the
practical sciences because those fields are naturally inclined to
a degree of vagueness. Aristotle is generally credited with being
the first thinker to recognize that knowledge is compartmentalized.
For example, he recognizes that the practical sciences, such as
ethics or politics, are far less precise in their methods and procedures
than, say, logic. This is not a failure of ethics and politics to
live up to some ideal, but rather just the nature of the beast.
Ethics and politics deal with people, and people are quite variable
in their behavior. In the Politics, Aristotle seems
to waver in determining what kind of constitution is best, but this
is not so much ambiguity on his part as a recognition that there
is no single best constitution. A thriving democracy relies on an
educated and unselfish population, and failing that, another form
of government might be preferable. Similarly, in the Nicomachean
Ethics, Aristotle does not lay down any hard and fast rules regarding
virtue because different behaviors are virtuous in different situations.
The vagueness of Aristotle’s recommendations regarding the practical
sciences are then a part and parcel of his general view that different
forms of study require different approaches.
The Unmoved Mover As First Cause
Aristotle’s theology is based on his perception that there
must be something above and beyond the chains of cause and effect
for those chains to exist at all. Aristotle perceives change and
motion as deep mysteries. Everything is subject to change and motion,
but nothing changes or moves without cause. Tracing how things cause
one another to change and move is the source of many of Aristotle’s most
fundamental insights. He believes that all causes must themselves
be caused and all motion must be caused by something that is already
in motion. The trouble with this belief is that it leads to an infinite
regress: if all causes have antecedent causes, there is no first cause
that causes motion and change to exist in the first place. Why is
there change and motion rather than stillness? Aristotle answers that
there must be a first cause, an unmoved mover, that is the source of
all change and motion while being itself unchanging and unmoving.
To motivate the heavens to move, this unmoved mover must be perfect,
so Aristotle comes to associate it with God.
