Mechanistic systems and their parts have no purposes of their own, but their
essential parts make possible the functioning of the whole. All mechanisms are
mechanistic systems. Plants are also. Clocks are common examples of such
systems; they operate with a regularity dictated by their internal structure and
the causal laws of nature. Neither the whole nor the parts of a clock display
choice, but they have functions. Similarly, an automobile is a mechanical
system that has no purpose of its own but serves its driver's and passengers' purposes.
In addition, an automobile's fuel pump (a mechanical system) has the function of supplying
its fuel injector or carburetor with fuel, without which
the automobile could not carry out its defining function.
Mechanistic systems are either open or closed, closed if their behavior is
unaffected by any external conditions or events; open if they are so affected.
The universe was conceptualized by Newton as a closed (self-contained)
mechanical system, with no environment-like a hermetically sealed clock. On
the other hand, the planet Earth is seen as an open system, one whose motion
is influenced by other bodies in the solar system.
These are conceptualized as purposeful systems whose parts have no
purposes of their own. The principal purpose of such systems is survival. A
person's lungs have no purpose of their own; but they function to enable a
person to extract oxygen from the environment so as to survive. Animate
systems are necessarily open; they must interact with their environments in
order to survive Understanding these interactions is essential for understanding their properties and behavior.
Animate systems are living systems. "Life" has been defined in many different
Ways. The definition now most widely accepted by biologists involves the ways
the maintenance of units and wholeness, while components
themselves are being continuously or periodically disassembled
and rebuilt, created and decimated, produced and consumed."
(Zeleny, 1981, p. 5)
From this definition it follows that social and ecological systems are also alive.
(Many biologists are unhappy about this consequence of their definition of 'life.')
These are systems that (1) have purposes of their own, (2) consist of parts at
least some of which are animate, hence have purposes of their own, and (3) are
a part of one or more larger (containing) systems that may have purposes of
their own and that may contain other social systems. For example, a local
government viewed as a social system is part of a state government, which is
also a social system, This, in turn, is part of a national government. Social
systems can be and usually are nested.
Such systems contain mechanistic, animate, and social systems as parts and,
therefore, containing some parts that have purposes of their own. However,
these systems as a whole are conceptualized as having no purpose of their own. Nature,
of course, is commonly taken to be an ecological system as is our
Ecological systems serve the purposes of their animate and social parts, and
provide necessary inputs to these and open deterministic systems. They also
provide a receptacle for their waste as well as their useful products. Such
service and support is their function.
An ecological system can be affected mechanistically by the mechanical or
purposeful behavior of its parts. For example, the purposeful use by people of
fluoro-carbons as a propellant and the emissions of power plants affect the
ozone layer mechanistically.
Animate and social systems are frequently confronted with situations in which
their choices can affect their effectiveness, either positively or negatively. Such
situations are problematic. In other words, problems are situations in which a
system's choice can make a significant difference to that system.