Three Kinds of Teleology

Whenever the explanation of some process or characteristic involves a goal or purpose at which it aims or which it serves, that explanation involves teleology. 

Teleological explanations fall into three large categories, distinct by their range and principles.  For the moment I will call them theological, evolutionary, and biological.

Theological teleology assumes a Theos or God who designs the universe and all that is in it with some purpose in mind.  God hangs the sun and the moon in the sky in order to provide a guiding light for man and His other creatures, as we read in the book of Genesis. 

Evolutionary teleology does not necessarily depend on any theological assumptions.  It argues that the processes by which the Kosmos and life on earth emerge and develop are goal directed.  Nature as a whole is striving for something.  Any account of life that involves goals on a species level falls into this category. 

Biological teleology simply recognizes that organic processes involve constant correction towards predetermined ends and that many traits of organisms can only be understood by their function. 

Natural theology, such as that presented by Thomas Aquinas, includes all three.  Natural theology is perfectly compatible with mechanical accounts of biological causation.  God does not necessarily have to intervene in the course of ontogeny if He so designed an individual organism to develop in a certain way. 

Aristotle recognized the second type of teleology.  He argues, in On the Generation of Animals, that the persistence of each species is the result of a striving toward the divine.  Whereas Divine beings are eternal, organisms admit of being and not being.  Individual organisms cannot escape this limitation, but the species can.  So, human beings cannot be eternal (and hence divine) numerically; however, the human being can be so, in the way that is open to it, genetically. 

Aristotle also recognized biological teleology.  Organisms develop and act toward certain ends and have traits that are explained by their function.  This is the only kind of teleology that is recognized by modern biological science.  While Aristotle’s view of the species/individual dichotomy is largely consistent with modern biology, his evolutionary teleology has no purchase.  Evolution is not a goal directed process, as Darwinian biology understands it. 

Theological teleology is necessarily outside the realm of science.  This is so not because of a lack evidence for God’s designing mind in the work of creation.  One may or may not take seriously such arguments as the appeal to cosmological constants as such evidence.  The problem is that the Theos is too powerful an explanatory factor.  An omnipotent God can do anything and therefore He explains everything.  For that very reason, He explains little or nothing in a scientific sense. 

It is probably a good thing that evolutionary teleology has been dispensed with.  While Aristotle’s version was benign, modern versions have underwritten such deplorable doctrines as Social Darwinism.  Evolutionary teleology has tended to be authoritarian.  Only retrograde people oppose the direction of evolution. 

Biological teleology helps us to understand why we care about what we care about.  It leaves us free to care most about what we should care about: living the best human lives individually and collectively.  If my love for my children is in large part a product of an evolutionary process by which my genes have managed to keep in play, fine.  Rejecting evolutionary teleology, I don’t have to give a rat’s ass about my genes.  I am free to care about my daughter and my son.