The Sundial Tribe and the Labyrinth of Purpose

Date of Award

May 2015

Degree Type


Degree Name

Doctor of Philosophy (PhD)




Thomas J. McKay

Second Advisor

Robert Van Gulick


evolution, formal semantics, language, philosophy of biology, teleological function, truth

Subject Categories

Arts and Humanities


I propose solutions to three problems of increasing specificity: naturalizing teleological functions; the semantics of natural language as embedded in context; and the meaning of linguistic expressions of disagreement about personal taste.

The concept of teleological function spans multiple domains---biologically evolved traits; intentional states such as beliefs and desires; actions; artifacts; customs, traditions, and institutions; social groups; and words, speech acts, and grammatical structures. When we ascribe a teleological function---e.g., the evolved function of the eye to aid sight, or the technological function of aspirin to reduce fever---we explain not only how a thing ought to function, but also why that thing exists. This is why, on the most popular contemporary theory of teleological function, the etiological theory (Millikan, Neander, etc.), the teleological functions of things are determined by the way these things came to exist: for actions and for many artifacts, intentional causation; for biological traits, evolution by natural selection.

This latter clause, however, has been shown to falsely exclude genuine teleological functions. To solve the difficulty I replace the standard requirement---for full-blown natural selection---with a different Darwinian requirement---for past contribution to the homestates of the systems that generated the bearers of teleological functions. In the sphere of biology, such generating systems include a trait's organism, this organism's ancestors and development, and natural selection itself. The kind of states I call homestates, well-known from cybernetics, are states that a system is disposed to reach from diverse initial conditions and in spite of a range of perturbations. For instance, the homestate of a target-seeking missile is to meet its target. I argue that the approach generalizes beyond biology to all teleological functions. When an entity x has the teleological function to cause E, this is in virtue of the fact that the causal explanation of x's origin places x under a norm to cause E and thereby to contribute to the homestates of x's generators.

Just like biological traits, utterances often perform their teleological functions in ways that rely on their environments, i.e., on their linguistic contexts. In light of this, I develop an externalist semantic view that I call mindless contextualism, the view that utterances embedded in context can semantically represent unintended constituents, i.e., that they can express propositions that go beyond the speakers' intentions. Imagine, for instance, that the members of the Sundial tribe migrate eastward and westward, that they tell the time only by sundials, and thus that they never become aware that the same hours come at different times in different places. Despite all this, they can still successfully and truthfully communicate about hours of day by saying such things as, "We dine at7 everywhere we go."

I position mindless contextualism within the contemporary debate between contextualism and relativism, and I argue that truth is not relative and that many of the phenomena commonly taken as arguments for relativism are, instead, signs of the presence of unintended constituents. I apply this approach to the problem of disagreement in matters of personal taste, a problem often used in the literature to model truth relativism, and I show how we can solve the problem in a way compatible with non-relative truth.


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