Teleology: A Shopper’s Guide

Teleology: A Shopper’s Guide

Edward Feser

The telos of a thing or process is the end or goal toward which it points. Teleological notions feature prominently in current debates in philosophy of biology, philosophy of action, philosophy of mind, and philosophy of religion. Naturalists generally hold that teleological descriptions of natural phenomena are either false or, if true, are reducible to descriptions cast in nonteleological terms. Nonnaturalists generally hold that at least some natu-ral phenomena exhibit irreducible teleology. For example, Intelligent Design (ID) theorists hold that certain biological phenomena cannot properly be un-derstood except as the products of an intelligence which designed them to carry out certain functions.

Teleology’s controversial status in modern philosophy stems from the mechanistic conception of the natural world, which early modern thinkers like Bacon, Galileo, Descartes, Hobbes, Boyle, and Locke put in place of the Aristotelian philosophy of nature that featured in medieval Scholasti-cism. Following Aristotle, the Scholastics took the view that a complete un-derstanding of a material substance required identifying each of its “four causes.” Every such substance is, first of all, an irreducible composite of substantial form and prime matter (irreducible because on the Scholastic view, substantial form and prime matter cannot themselves be understood apart from the substances they compose, making the analysis holistic rather than reductionist). The substantial form of a thing is its nature or essence, the underlying metaphysical basis of its properties and causal powers; it con-stitutes a thing’s formal cause. Prime matter is the otherwise formless stuff that takes on a substantial form so as to instantiate it in a concrete object, and apart from which the form would be a mere abstraction; it constitutes a thing’s material cause. That which brings a thing into existence constitutes its efficient cause. And the end or goal towards which a thing naturally points is its final cause.1As the last sentence indicates, the notion of a final cause is closely tied to that of a telos and thus to the notion of teleology. But the adverb “naturally” is meant to indicate how the Aristotelian notion of final cause differs from other conceptions of teleology. For Aristotle and for the Scholastics, the end or goal of a material substance is inherent to it, something it has precisely be-cause of the kind of thing it is by nature. It is therefore not to be understood on the model of a human artifact like a watch, whose parts have no inherent tendency to perform the function of telling time, specifically, and must be forced to do so by an outside designer. For example, that a heart has the func-tion of pumping blood is something true of it simply by virtue of being the kind of material substance it is, and would remain true of it whether or not it has God as its ultimate cause.

In the sections that follow, I aim to provide a “shopper’s guide” of sorts for philosophers interested in questions about teleology, in the course of which I will expand upon some of the historical and conceptual themes already alluded to. Specifically, I will show in the second section, “Five Ap-proaches to Teleology,” that the question of whether teleology exists in na-ture is not susceptible of a simple “yes or no” answer, but that there are in fact five main positions that can and have been taken on the issue. In the third section, “Levels of Teleology,” I will show that there are also at least five levels of nature at which irreducible teleology might be claimed to ex-ist, so that to establish that it exists or does not exist at one of them does not suffice to determine whether it exists at the others. With at least five levels of nature at which teleology might be said to exist, and five possible ways in which to conceive of teleology at any of these levels, the conceptual lay of the land can be seen to be complex indeed. Finally, in the last section I will address the implications of these conceptual distinctions for the debate over teleological arguments for the existence of God. In particular, I will explain how the approach taken by philosophers committed to A-T metaphysics dif-fers radically from that taken by ID theorists and defenders of Paley-style design arguments. In the process I hope to shed light on a phenomenon that many ID theorists seem to find puzzling, namely, that Thomists, who would seem to be their natural allies in the dispute with naturalism, are typically very critical of ID. As we will see, this state of affairs has less to do with disagreements about the merits of Darwinian evolutionary biology (though it does sometimes have something to do with that) than it has to do with disagreements over basic metaphysics—disagreements which, for the A-T metaphysician, show that the ID theorist is (surprising as this might seem) philosophically closer to the Darwinian naturalist than to A-T