Written By Thomas Perez. August 10, 2010 at 7:39PM. copyright 2010.
The teleological argument (or the “argument from design”) is an argument for God’s existence based on the belief that the complexity in the universe argues for a creator. The title “teleological” comes from the Greek word telos which means “purpose” or “design.” The teleological argument goes like this: The universe and its contents evidence great complexity. Since great complexities such as the human body and the movements in our solar system cannot happen by random chance, some powerful and intelligent being must have created the universe. This divine architect is God. One modern proponent of the teleological argument was William Paley (1743-1805) who used the analogy of a watch to promote the view that God created the world. According to Paley, just as a watch implies the existence of a watchmaker, the function and complexity of the universe implies that there is a universe-maker. Some believe that David Hume seriously damaged the validity of the teleological argument when he challenged traditional views concerning cause and effect. There have been three traditional responses to the teleological argument. First, some say the teleological argument is guilty of a “weak analogy” because it assumes a significant resemblance between natural objects (I.e., rocks, trees) and objects we know have been designed (ex. watches, skyscrapers). Second, some say that the theories of the big bang and evolution better explain the complexities in the universe. Third, some say that even if the teleological argument is true, it does not prove the existence of the Christian God.
Nevertheless, the teleological argument has many proponents and is still considered to be one of the strong natural evidences for the existence of God.
1. Design Inference Patterns
The historical arguments of interest are precisely the potentially problematic ones—inferences beginning with some empirical features of nature taken as (or argued to be) design-indicative, and concluding with the designedness of, and a designer of, the phenomena in question. A standard but separable second step—the natural theology step—involves identifying the designer as God, often via particular properties and powers required by the designing in question. Although the argument wielded its greatest intellectual influence during the 18th and early 19th centuries, it goes back at least to the Greeks and in extremely clipped form comprises one of Aquinas’s Five Ways. It was given a fuller and quite nice early statement by Hume’s interlocutor Cleanthes:
Look round the world; contemplate the whole and every part of it: You will find it to be nothing but one great machine, subdivided into an infinite number of lesser machines, which again admit of subdivisions to a degree beyond what human senses and faculties can trace and explain. All these various machines, and even their most minute parts, are adjusted to each other with an accuracy which ravishes into admiration all men who have ever contemplated them. The curious adapting of means to ends, throughout all nature, resembles exactly, though it much exceeds, the productions of human contrivance; of human design, thought, wisdom, and intelligence. Since, therefore, the effects resemble each other, we are led to infer, by all the rules of analogy, that the causes also resemble; and that the Author of Nature is somewhat similar to the mind of man, though possessed of much larger faculties, proportioned to the grandeur of the work which he has executed. By this argument a posteriori, and by this argument alone, do we prove at once the existence of a Deity, and his similarity to human mind and intelligence. (Hume 1779 , 15).
That statement captures much of popular, informal design intuitions, but exactly how ought we to construe the formal structure of such arguments? What sort of logic is being employed? As it turns out, that question does not have just a single answer. Several distinct answers are canvassed in the following sections.
1. Analogical Design Arguments: Schema 1
Design arguments are routinely classed as analogical arguments—various parallels between human artifacts and certain natural entities being taken as supporting parallel conclusions concerning operative causation in each case. (Note that Cleanthes, above, specifically appeals to “the rules of analogy.”) The standardly ascribed schema is roughly thus:
Entity e within nature (or the cosmos, or nature itself) is like specified human artifact a (e.g., a machine) in relevant respects R.
a has R precisely because it is a product of deliberate design by intelligent human agency.
Like effects typically have like causes (or like explanations, like existence requirements, etc.)
It is (highly) probable that e has R precisely because it too is a product of deliberate design by intelligent, relevantly human-like agency.
(The relevant respects and properties R are referred to variously as teleological properties or as marks or signs of design, and objects having such properties are sometimes referred to as teleological objects. For simplicity and uniformity of discussion, I shall simply talk in terms of “Rs”.)
This general argument form was criticized quite vigorously (and familiarly) by Hume, at several key steps. (Hume’s primary critical discussion is contained in (Hume 1779 ). Hume’s responses are widely taken as the paradigm philosophical refutation of traditional design arguments.) Against (1), Hume argued that the analogy is not very good—that nature and the various things in it are not very like human artifacts and exhibit substantial differences from them—e.g., living vs. not, self-sustaining vs. not. Indeed, whereas advocates of design arguments frequently cited similarities between the cosmos on the one hand and human machines on the other, Hume suggested (tongue perhaps only partly in cheek) that the cosmos much more closely resembled a living organism than a machine. But if the alleged resemblance is in relevant respects distant, then the inference in question will be logically fragile. And while (2) may be true in specific cases of human artifacts a, that fact is only made relevant to natural phenomena e via (3), which underpins the transfer of the key attribution. Against (3), Hume argued that any number of alternative possible explanations could be given of allegedly designed entities in nature—chance, for instance, or saturation of the relevant state space of possibilities. Thus, even were (1) true and even were there important resemblances, the argument might confer little probabilistic force onto the conclusion.
More generally, Hume also argued that even if something like the stated conclusion (4) were established, that left the arguer far from anything like a traditional conception of God. For instance, natural evils or apparently suboptimal designs might suggest e.g., an amateur designer or a committee of designers. And if phenomena instrumental to the production of natural evils (e.g., disease microorganisms) exhibited various of the Rs, then they would presumably have to be laid at the designer’s door, further eroding the designer’s resemblance to the wholly good deity of tradition. And even the most impressive empirical data could properly establish only finite (although perhaps enormous) power and wisdom, rather than the infinite power and wisdom usually associated with divinity. But even were one to concede some substance to the design arguments’s conclusion, that would, Hume suggested, merely set up a regress. The designing agent would itself demand explanation, requiring ultimately a sequence of prior analogous intelligences producing intelligences. And even were the existence of a designer of material things established, that did not yet automatically establish the existence of a creator of the matter so shaped. And of course the argument being inductive, the conclusion even if established would be established only to some, perhaps insignificant, degree of probability. Furthermore, we could not ground any induction concerning the cosmos itself upon a requisite fund of experiences of other cosmoi found to be both deliberately designed and very like ours in relevant respects—for the simple reason that this was the only one we had (or could) experience. And the fraction of this one cosmos (both spatially and temporally) available to our inspection was more or less indistinguishable from zero—not a promising basis for a cosmically general conclusion. Hume concluded that while the argument might constitute some limited grounds for thinking that “the cause or causes of order in the universe probably bear some remote analogy to human intelligence” (Hume 1779 , 88) Hume’s emphasis)—and that is not a trivial implication—it established nothing else whatever.
Historically, not everyone agreed that Hume had fatally damaged the argument. For one thing, some of Hume’s criticisms rested upon his own peculiar conception of causation—a conception nearly universally recognized as seriously inadequate. Further it is simply not true that explanatory inferences cannot properly extend beyond merely what is required for known effects. As a very general example, on the basis of the few observations which humans had made during a cosmically brief period in a spatially tiny part of the cosmos, Newton theorized that all bits of matter at all times and in all places attracted all other bits of matter. There was nothing whatever logically suspect here. Indeed, simplicity and uniformity considerations—which have considerable well-earned scientific clout—push in the direction of such generalizations.
But Hume certainly identified important places within the argument to probe. First, any two (groups of) things have infinitely many properties in common and also differ in infinitely many respects. Whether or not artifacts and natural objects are alike in ways that would support transfer of design attributions from the former to the latter depends upon exactly what the relevant Rs are. And since artifact cases will have multiple properties which they would not have were the object not an artifact—e.g., being on my table—but which are not themselves conceptually indicative of design, whether or not the Rs in question will serve design argument purposes will depend on whether they are somehow especially linked to design even in the artifact case. Second, whether or not there really are alternative means of producing Rs independent of any mind input is often an empirical matter, which cannot be settled either way by simple stipulation. On the other hand, whether or not some of Hume’s own remarks are to the point depends upon whether or not design arguments really are ultimately analogical. And whether or not Hume’s suggestions are correct concerning the uncertain character of any designer inferred will depend upon the specific Rs and upon what can or cannot be definitively said concerning requirements for their production.
R Concerns Round 1
Key questions, then, include: what are the relevant Rs typically cited? do those Rs genuinely signal purpose and design? how does one show that either way? are there viable alternative accounts of the Rs requiring no reference to minds? how does one show that either way? The specific Rs in question are obviously central to design argument efforts. Although the underlying general category is, again, some special type of orderliness, the specifics have ranged rather widely historically. Among the more straightforwardly empirical are inter alia uniformity, contrivance, adjustment of means to ends, particularly exquisite complexity, particular types of functionality, delicacy, integration of natural laws, improbability, the fitness (fine-tuning) of the inorganic realm for supporting life, significant temporal or spatial co-incidings, and significant isomorphisms. Some advocates cited what might be termed second-order properties as well. For instance, in the 1820s William Sharp MacLeay argued that taxonomic structures (cascades of quintets of taxonomic categories, as he saw it) constituted evidence of design. A number of empirically further removed and problematic proposals all having axiological overtones have also been advanced, including the intelligibility of nature, the directionality of evolutionary processes, aesthetic characteristics (beauty, elegance, and the like), apparent purpose and value (including the aptness of our world for the existence and practice of moral value) and just the sheer niftiness of many of the things we find in nature. (“Cumulative” arguments involving intermeshings of multiple of the above factors have also been advanced.)
Many of the specific Rs advanced historically were vulnerable to substantive critiques, often increasingly so as time went on. Specifically, while it was clearly evident that various a‘s had the R character they did in virtue of their (human) intentional production, it was much more difficult establishing that any or all other occurrences of R likely owed their existence to intention as well. As the standard story has it, science increasingly acquired understandings of how nature unaided by deliberate intent and planning could produce virtually any R proposed, and thus while (2) might continue to hold for virtually any human artifact a having any intended R one might please, (3) — and consequently the inference to (4) — became progressively less defensible. Design, on this telling, might gradually be explained away.
2. Deductive Design Arguments: Schema 2
But some advocates of design arguments had been reaching for a deeper intuition. The intuition they were attempting to capture involved properties that in and of themselves constituted some degree of evidence for design—properties that were not merely constantly conjoined, for whatever reason, with instances of design. The specific Rs were singled out not just because such properties happened to be often or even only produced by designing agents. (Garbage heaps fit that description.) Advocates were convinced that the appropriate Rs in question were in their own right directly reflective of and redolent of cognition, that this directly suggested mind, that we could see nearly directly that they were the general sort of thing that a mind might or even would generate, and that consequently they did not depend for their evidential force upon previously established constant conjunctions or other associations with known instances of design. When we see a text version of the Gettysburg Address, that text says mind to us in a way totally unrelated to any induction or analogy from past encounters with written texts. It was that type of testimony to mind, to design, that some historical advocates of design arguments believed that they found in some Rs observed in nature—a testimony having no dependency on induction or analogy. Beauty, purpose and in general value especially when conjoined with delicate complexity were popular underlying intuitive marks. Intricate, dynamic, stable, functioning order of the sort we encounter in nature was frequently placed in this category. Such order was taken to be suggestive of minds in that it seemed nearly self-evidently the sort of thing minds, and so far as was definitively known, only minds were prone to produce. It was a property whose mind-resonating character we could unhesitatingly attribute to intent.
Despite Hume’s earlier demurs that things in nature are not really very like artifacts such as machines, most people (including opponents of design arguments) who are most familiar with nature’s dazzling intricacies freely admit that nature abounds with things that look designed—that are intention-shaped. For instance, Francis Crick (no fan of design) issued a warning to his fellow biologists:
Biologists must constantly keep in mind that what they see was not designed, but rather evolved. (Crick 1988, 138).
Along with this perception of mind-suggestiveness went a further principle—that the mind-suggestive or intention-shaped (the design-like) characteristics in question were too palpable to have been generated by non-intentional means.
That allows specification of a second design inference pattern:
Some things in nature (or nature itself, the cosmos) are design-like (exhibit a cognition-resonating, intention-shaped character R)
Design-like properties (R) are not producible by (unguided) natural means—i.e., any phenomenon exhibiting such Rs must be a product of intentional design.
Some things in nature (or nature itself, the cosmos) are products of intentional design. And of course, the capacity for intentional design requires agency of some type.
Notice that explicit reference to human artifacts has dropped out of the argument, and that the argument is no longer comparative but has become essentially deductive. Some arguments were historically intended as arguments of that type. Consider the widely reproduced opening passages of William Paley’s 1802 Natural Theology:
In crossing a heath, suppose I pitched my foot against a stone and were asked how the stone came to be there, I might possibly answer that for anything I knew to the contrary it had lain there forever; nor would it, perhaps, be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place. I should hardly think of the answer which I had before given, that for anything I knew the watch might have always been there. Yet why should not this answer serve for the watch as well as for the stone? Why is it not as admissible in the second case as in the first? For this reason, and for no other, namely, that when we come to inspect the watch, we perceive—what we could not discover in the stone—that its several parts are framed and put together for a purpose … [The requisite] mechanism being observed … the inference we think is inevitable, that the watch must have had a maker. … Every observation which was made in our first chapter concerning the watch may be repeated with strict propriety concerning the eye, concerning animals, concerning plants, concerning, indeed, all the organized parts of the works of nature. … [T]he eye … would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator. …
Although Paley’s argument is routinely construed as analogical, it in fact contains an informal statement of the above variant argument type. Paley goes on for two chapters discussing the watch, discussing the properties in it which evince design, destroying potential objections to concluding design in the watch, and discussing what can and cannot be concluded about the watch’s designer. It is only then that entities in nature—e.g., the eye—come onto the horizon at all. Obviously, Paley isn’t making such heavy weather to persuade his readers to concede that the watch really is designed and has a designer. He is, in fact, teasing out the bases and procedures from and by which we should and should not reason about design and designers. Thus Paley’s use of the term ‘inference’ in connection with the watch’s designer.
Once having acquired the relevant principles, then in Chapter 3 of Natural Theology—“Application of the Argument”—Paley applies the same argument (vs. presenting us with the other half of the analogical argument) to things in nature. The cases of human artifacts and nature represent two separate inference instances:
up to the limit, the reasoning is as clear and certain in the one case as in the other. (Paley 1802 , 14)
But the instances are instances of the same inferential move:
there is precisely the same proof that the eye was made for vision as there is that the telescope was made for assisting it. (Paley 1802  13)
The watch does play an obvious and crucial role—but as a paradigmatic instance of design inferences rather than as the analogical foundation for an inferential comparison.
Schema 2, not being analogically structured, would not be vulnerable to the ills of analogy, and not being inductive would claim more than mere probability for its conclusion. That is not accidental. Indeed, it has been argued that Paley was aware of Hume’s earlier attacks on analogical design arguments, and deliberately structured his argument to avoid the relevant pitfalls. Paley’s own characterization of his argument would support this deductive classification. For instance, after presenting the argument, Paley refers to
… the marks of contrivance discoverable in animal bodies, and to the argument deduced from them in proof of design and of a designing Creator [my emphasis]
Of course, “deduced” is often used quite loosely—Sherlock Holmes, for instance, was notoriously less than rigorous on that point. But Paley, shortly after the above, says:
The eye proves it … The proof … is complete; for when the design of the part and the conduciveness of its structure to that design is shown, the mind may set itself at rest; no future consideration can detract anything from the force of the example.
That characteristic—impossibility of additional information weakening the logic of an inference—is definitive of deductive arguments, but does not apply to inductive arguments at all.
Assessing the Schema 2 Argument
First, how are we to assess the premises required by this schema? Premise (5), at least, is not particularly controversial even now. Crick’s earlier warning to biologists would have been pointless were there no temptation toward design attributions, and even as implacable a contemporary opponent of design arguments (and all things remotely related to them) as Richard Dawkins characterized biology as:
the study of complicated things that give the appearance of having been designed for a purpose. (Dawkins 1987, 1)
Day-to-day contemporary biology is rife with terms like ‘design’, ‘machine’, ‘purpose’ and allied terms. And that is not just arbitrary convention, but may be virtually inescapable. Indeed, Kant, although a critic of design arguments, saw design as a regulative principle of science—that is, a principle which, whether true or not, science could not operate without. As historian of science Timothy Lenoir has remarked:
Teleological thinking has been steadfastly resisted by modern biology. And yet, in nearly every area of research biologists are hard pressed to find language that does not impute purposiveness to living forms. (Lenoir 1982, ix)
Whether or not particular biological phenomena are designed, they are frequently enough design-like to make design language (resisted or not) not only fit living systems extraordinarily well, but to undergird generation of fruitful theoretical conceptions as well. (Advocates of design arguments claim that the reason why theorizing as if organisms are designed meets with such success is that organisms are in fact designed.)
However principle (6) (that the relevant design-like properties are not producible by unguided natural means) will be more problematic. (It should be noted that the conceptual relevance of having R to being designed is of implicit importance even to specifically analogical arguments, since such relevance considerations constitute one important evaluative criterion for analogical arguments.) What might be the rational justification for (6)? There are two broad possibilities.
1. Empirical: induction. Induction essentially involves establishing that some principle holds within the realm of our knowledge/experience (the sample cases), and then, subject to certain constraints, generalizing the principle to encompass relevant areas beyond that realm (the test cases). The attempt to establish the universality of a connection between having relevant Rs and being a product of mind on the basis of an observed consistent connection between having relevant Rs and being a product of mind within all (most) of the cases where both R was exhibited and we knew whether or not the phenomenon in question was a product of mind, would constitute an inductive generalization.
This approach would suffer from a variety of weaknesses (some of them related to Hume’s criticisms of Schema 1 arguments). First, there would be at least some awkwardness in that the overwhelming bulk of the R-exhibiting cases of which we were aware would be exactly the problematic cases—those in nature. More truly problematic would be the fact that the R-exhibiting things concerning which we knew whether or not they were designed would be almost without exception human artifacts, whereas the phenomena to which the generalization was being extended would be almost without exception things in a very different category—things in nature. And, of course, the generalization in question could establish at best a probability, and the factors just noted would keep the specific probability fairly modest.
2. Conceptual. It might be held that (6) is known in the same conceptual, nearly a priori way in which we know that textbooks are not producible by natural processes unaided by mind. And our conviction here is not based on any mere induction from prior experiences of texts. Texts carry with them essential marks of mind, and indeed in understanding a text we see at least partway into the mind(s) involved. Various alien artifacts (if any)—of which we have had no prior experience whatever—could fall into this category as well. Similarly, it has been held that we sometimes immediately recognize that order of the requisite sort just is a sign of mind and intent.
Alternatively, it could be argued that although there was a genuine conceptual link between appropriate Rs and mind, design, intent etc., that typically our recognition of that link is triggered by specific experiences with artifacts, or that our seeing the connections in depth is best elicited by considerations involving artifacts. (Both Aristotle and Galileo held a correlate of this view concerning our acquiring knowledge of the general principles governing nature.) On this view, once the truth of (6) became manifest to us through experiences of artifacts, the appropriateness of its more general application would be clear. That might explain why so many advocates of design arguments—both historical and current—seem to believe that they must only display a few cases and raise their eyebrows to gain assent to design.
Either way, principle (6), or something like it, would be something with which relevant design inferences would begin. Further investigation of (6) requires taking a closer look at the Rs which (6) involves.
R Concerns: Round 2
One thing complicating general assessments of design arguments is that the evidential force of specific Rs is affected by the context of their occurrence. Specifically, properties which seem clearly to constitute marks of design in known artifacts often seem to have significantly less evidential import outside that context. For instance, we typically construe enormous complexity in something known to be a manufactured artifact as a deliberately intended and produced characteristic. But mere complexity in contexts not taken to involve artifacts (the precise arrangement of pine needles on a forest floor, for instance) does not seem to have that same force. In the case of natural objects with evident artifactuality absent, it is less clear that such complexity – as well as the other traditional empirical Rs – bespeaks intention, plan and purpose. Similarly, absolutely straight lines in an artifact are typically results of deliberate intention. That straight lines traveled by light rays is so would seem to many to be less obvious.
Furthermore, even within those two contexts—artifact and nature—the various Rs exhibit varying degrees of evidential force. For instance, even in an artifact, mere complexity of whatever degree speaks less clearly of intent than does an engraved sentence. And most critics of design arguments (even among theists) would claim that the categories of evidences we find in nature are far removed from the ‘engraved sentence’ end of the evidential spectrum. Most of the characteristics which uncontroversially shout “intent” are connected most readily to evident artifacts, and are not among the marks we find in nature.
There are two crucial upshots. First, notice that in general, the more empirically tractable the specific Rs, the less promising as marks of purpose and design they seem. For instance, if just bare complexity is cited, then although complexity is in many respects easily demonstrable, that complexity does not just uncontroversially speak of intent. On the other hand, although the exhibiting of genuine purpose and value might constitute persuasive and even compelling evidence of a designer, establishing that the empirical characteristics in question really do betoken genuine purpose and value – and not just, say, functionality – seems to many to be difficult if not impossible.