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Changing the Mission of Theories of Teleology: DOs and DON’Ts for

Thinking About Function

Teleology has a long history. Religious doctrines often give teleology a central role—the
gods infuse Nature with their own goals and purposes, and rains and droughts and
earthquakes occur to bring about divine goals, or a single God is said to instill functions
by design throughout Creation. These views seek to explain natural events on the model
of something we think we understand—intelligent human creation of objects for a purpose.
Aristotle made generous use of teleology in describing objects, organisms, and their
interactions, and even as the basis of ethics and metaphysics. This cornerstone of his
philosophy remained infl uential for more than eighteen hundred years. But with the
Scientifi c Revolution and the Enlightenment, talk of the function of natural objects,
teleological function, began to be viewed with suspicion as the mechanical model of
the world replaced the old Aristotelian model. To a large degree nonnatural explanations
based on religion have given way to science. Yet there are still areas of nature that
seem at their core to involve teleological functions—the parts of organisms. Biology
seems to be unable to do without functions, and even after science rejected functions
so forcefully, it became clear that even a dedication to naturalistic explanation seems
to require retaining tele ological functions. So philosophers grudgingly allowed functions,
albeit on a Deductive-Nomological model of explanation with cumbersome and unwieldy
formulations that really didn’t put any explanatory weight on functions being an impor-
tant part of scientifi c explanation.
The modern philosophical movement to legitimize teleology began in the early 1970s,
with Wright’s 1973 paper “Functions,” which proposed a defi nition of function that was
naturalistic, historical (or etiological) in nature, simple, and elegant:

The function of X is Z means:

(a) X is there because it does Z, and
(b) Z is a consequence (or result) of X’s being there.

This was joined by a 1976 book by Wright and important papers by Boorse (1976, 1977),
Wimsatt (1972), Mayr (1974), Woodfi eld (1976), and others. In 1975, Robert Cummins’s

Mark Perlman