Mechanistic Systems

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.

Animate Systems

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 concept autopoiesis:

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.')

Social Systems

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.

Ecological Systems

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 environment.

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.