Last time we defined key terms in this section on teleology or design. Before we can conclude our survey of definitions we need to do a more thorough comparison of “purpose” and “function.” In The Encyclopedia of Philosophy, Morton Beckner explores the distinction between them as the crux of teleology.2 Purpose by his account can be logically independent of intention or consciousness and is directed, persistent, and sensitive to a goal.The goals of systems that exhibit purposive behavior are the outcome of relatively independent dovetailing processes – that is ‘directive correlation.’
He uses the example of a guided missile where the independent processes are position of the target and the direction of the missile as opposed to the non-purposive activity of a river flowing to the sea. Therefore “activity is purposive if and only if it exhibits sensitivity and persistence to a goal as a result of directive correlation.”
On the other hand, functions are contributions to fundamental processes (e.g. kidney functions for excretion; or hair functions to aid in maintaining body temperature). They are part of a hierarchy of functions leading to a process, but lack sensitivity and persistence to a goal. Beckner admits the distinction between function and purpose is arguable, but makes a good case for the distinction.
In any case, a concluding summary of the definitions in the last post and Beckner’s analysis in this allows creation of the following table:
Thus purpose and meaning address why things occur while design and chance attend to how they occur. Function straddles these designations while intention and direction are more neutral words although connotatively tend to imply how and even why things happen.
Our next step is to look at chance and its relatives – complexity and chaos – as explanations of things and events in the universe.
1Webster’s New Universal Unabridged Dictionary, Barnes & Noble, Inc. 2003. ISBN 0-7607-4975-2, p. 1952.
2Edwards, Paul (editor), The Encyclopedia of Philosophy. Macmillan Publishing Co., Inc. & The Free Press, 1972. Volume 8, pages 88-91.