The term teleology locates a series of connected philosophical questions. If we grant that there is such a thing as purposive or goal-directed activity (as we must, since, for example, a political campaign aimed at victory represents a clear, uncontroversial case), we may ask the following questions: (1) By what criteria do we identify purposive activity? (2) What is the nature of the systems that exhibit purposive activity? (3) Does the nature of purposive activity require us to employ special concepts or special patterns of description and explanation that are not needed in an account of nonpurposive activity? And if we grant that there are objects and processes which perform functions (again, as we must, since no one would deny, for instance, that the human kidney performs the function of excretion), we may ask: (4) By what criteria do we identify functions? (5) What is the nature of the systems that exhibit functional activity? (6) Does the description of functions require special concepts or special patterns of analysis?
These six questions have been formulated with the help of a distinction between purposive and functional activity. Although the distinction is not always drawn in discussions of teleology, it is desirable for a number of reasons. It seems, at least prima facie, that the criteria of functional activity are quite distinct from the criteria of purposive activity: urine excretion, for example, seems to be a function by virtue of its role in the economy of a living organism, whereas activity seems to be purposive in virtue of the manner in which it is controlled. Thus, it seems at least logically possible that a purposive activity could perform no function, and that a function could be performed without purposive activity. Moreover, in view of this fundamental conceptual difference between purpose and function, we should expect the analysis of purposive and functional activity to show differences in logical pattern. On the other hand, it also seems clear that there are close connections between function and purpose; thus the final question: (7) What is the relation between ascriptions of function and ascriptions of purpose?
A number of writers have proposed definitions of "goal-directed" or "purposive" action that leave open the question whether the action is intentional or in any way involves consciousness. R. B. Braithwaite suggests, as a behavioral criterion of goal-directed activity that either may or may not be goal-intended, "persistence toward the goal under varying conditions." This is a condensed version of very similar criteria offered by R. B. Perry, E. S. Russell, and A. Hofstadter. All presuppose that a goal may be identified and that both persistence and sensitivity to varying conditions may be located by reference to the goal. E. C. Tolman adds the requirement that purposive activity show "docility," that is, some improvement in reaching the goal in the course of successive trials. But docility, however important it may be in the total picture of biological purposiveness, is surely not part of the criterion of purposiveness. Any abilities that are in fact learned could, in logical principle, be innate.
This criterion, in Braithwaite's form, is of course susceptible of considerable refinement; Braithwaite himself (in Scientific Explanation ), for example, proposes a way of identifying variations in conditions as relevant variations for applying the criterion. Further possible refinements will be discussed in the next section.
The apparent circularity in the criterion—defining "goal-directed" in terms of a "goal"—is not serious. The location of persistence, sensitivity, and a goal may proceed together by a method of successive approximations. For example, a pattern of animal behavior may appear persistent and lead to a tentative identification of a goal, and the identification may be checked by looking for sensitivity to conditions or further evidence of persistence. A hypothesis about any one of the three—goal, persistence, sensitivity—can be confirmed by investigating either of the other two.
It seems clear that there are behavioral criteria for identifying purposive action, not only of human beings but also of other animals and of artifacts such as self-guided missiles. A pilot who watches a rocket approach in spite of his evasive maneuvers would rightly have no doubts about either the goal-directedness of the rocket's movements or the identity of its goal. No doubt the actual criteria of purposiveness that have been proposed suffer various shortcomings. In particular, they seem to lay down a necessary but not a sufficient condition. However, most philosophers would regard the program of seeking behavioral criteria as sound.
nature of systems showing purposive activity
Is it possible for the philosopher, as distinct from the biologist, psychologist, or communications engineer, to say anything illuminating about the nature of the systems—men, mice, and missiles—that engage in purposive activity? He can at least examine more closely the behavioral criteria of purposiveness, in order to see whether there might be covert reference to the nature of the system in the criterias' actual application. A critic of the behavioral criteria might remark that a river is persistent in reaching the sea and is sensitive to the conditions necessary for reaching the sea—it detours all obstacles—but we would not call the flowing of a river purposive, nor would we call the sea or reaching the sea its goal. In short, the critic might say, a river is not the sort of thing to which we ever ascribe purposiveness.
A number of philosophers, including Braithwaite, Ernest Nagel, George Sommerhoff, and Morton Beckner, have proposed ways of avoiding the difficulty about rivers and the like. Although there are differences in their accounts, they all adopt the strategy of regarding an activity as purposive only when its goal-seeking character is the outcome of relatively independent but dovetailing processes. Sommerhoff, for example, defines "purposive behavior" with the help of a concept he terms "directive correlation." Two variables, such as the position of a moving target and the direction in which an automatic target-tracking mechanism points, are said to be directively correlated with respect to a goal state (in this case, the state in which the mechanism points at the target) whenever: (1) The two variables are independent in the sense that any value of one is compatible with any value of the other; (2) The actual value of both, at a given time, is at least in part causally determined by the prior value of a "coenetic" (steering) variable (in the example, the coenetic variable is the same as one of the directively correlated variables, namely, the position of the moving target); and (3) the causal determination is such that the actual values of the directively correlated variables are sufficient for the realization of the goal state. Sommerhoff then defines "purposive behavior" as directively correlated behavior in which the coenetic variable is identical with one of the directively correlated variables.
Stipulations (2) and (3) make the notion of two processes dovetailing so as to achieve a goal as precise as the notion of causal determination; and stipulation (1) specifies that the processes must be independent. The requirement of independence rules out such cases as the river, for the direction in which a river flows is not independent of the lay of the land.
Sommerhoff's analysis is not without difficulties (see Nagel and Beckner), but it is undoubtedly correct in general approach. A system S that could exhibit directive correlation would satisfy a number of prior conceptions about purposive behavior; for instance, that S would employ information about its environment, particularly about an aspect of the environment associated with the goal, and that the behavior of S would be dependent upon a specialized physical hookup, such as some sort of circuitry.
It is now possible to suggest a schema for constructing a criterion of purposive activity that includes both a necessary and a sufficient condition and that incorporates some reference both to the empirical character of the activity and to the nature of the system that engages in it. Activity is purposive if and only if it exhibits sensitivity and persistence toward a goal as a result of directive correlation.
need for special concepts or patterns of description and explanation
Purposive activity, in the analyses of Braithwaite and Sommerhoff described above, does not involve a special kind of causality but only a special organization of ordinary causal processes. If these analyses are correct, both living organisms and artificial machines are capable of purposive activity. If, therefore, special concepts or patterns of description and explanation are not needed in the case of purposive machines, it would appear that they are equally unnecessary in the case of organisms. Many philosophers have drawn this conclusion, and it must be admitted that accounts like Braithwaite's and Sommerhoff's constitute powerful arguments in its support.
There is room for some doubt, however. Even if we grant that purposive activity can be defined in terms that are equally applicable to organic and inorganic systems, it does not follow that all purposive activity can be explained on the model of inanimate activity. The most serious doubt concerns those purposive activities that may be described as the acts of agents, such as acts deliberately undertaken for the sake of a consciously envisaged end. Suppose, for example, that some or all of these acts of agents are in principle unpredictable—a view accepted by some philosophers. Then, if they can be explained at all, their explanation is essentially post hoc. The pattern of such explanation is not yet properly understood; nevertheless, there is at least some doubt that it can dispense with the conception of following a rule. But these considerations raise questions that cannot be pursued here.
When we assert truly—for example, that a function of the kidney is the excretion of urine—precisely what relations must hold between the kidney and excretion? It has been proposed, for example by Nagel, that such teleological terms as purpose and function can be eliminated in the following way: An expression such as "A function of the kidney is the excretion of urine" is translated into the nonteleological expression "The kidney is a necessary (or necessary and sufficient) condition of urine excretion." In general we may interpret Nagel as proposing a translation schema—For "F is the function of A, " write "A is a necessary (or necessary and sufficient) condition of F "—that dispenses with teleological language and that also provides part of a criterion (a necessary condition) for identifying functions.
At best, however, Nagel's schema must be modified, for the possession of kidneys is neither a necessary nor a sufficient condition of urine excretion. It is obviously not sufficient; but it is also not necessary, since urine can also be excreted by various artificial devices. (If it is objected that these devices are themselves a sort of kidney, then the statement that a kidney is necessary for excretion reduces to a tautology.) Moreover, the translation schema is much less plausible when applied to organic functions that are ordinarily accomplished in distinct ways. Temperature regulation, for example, is a function of man's body hair; but hair is not necessary for heat regulation, since the function may be performed by other physical and physiological mechanisms. When we ascribe a function to the kidney or to body hair, we seem to be saying no more than that these structures contribute to certain processes; we leave open the question whether they are necessary or sufficient for the processes. The relation "contributing to" may be defined without employing teleological language. Let F be a process, some or all of which takes place in system S ; and let A be a part of, or a process in, S. Finally, let the terms "S -like," "F -like," and "A -like" refer, respectively, to all those entities that answer to the definition of the terms employed in specifying S, F, and A. (In the example "A function of the kidney in vertebrates is the excretion of urine," all vertebrates are S -like, all cases of urine excretion are F -like, and all kidneys are A -like.) Then "A of S contributes to F " if and only if there exist S -like systems and states or environments of these S -like systems in which F -like processes occur and the possession of A -like parts or processes is necessary for the occurrence of F -like processes.
On this definition, we may say that in general a man's kidney contributes to the excretion of urine and that body hair contributes to heat regulation. And if we adopt the translation schema "For 'F is the function of A in S, ' write 'A contributes to F in S, '" we may say, even in the case of a man whose bad kidneys have been bypassed to an artificial kidney, that the function of his flesh-and-blood kidneys is still the excretion of urine; they merely fail to perform it.
nature of systems showing functional activity
Nagel's translation schema and the above modification of it provide a way of translating a teleological statement T 1 into a statement T 2 that does not employ explicitly teleological terms. Therefore, the satisfaction of T 2 by a given A, F, and S is a necessary condition of F 's being a function of A. It is, however, not a sufficient condition; we may not in general translate T 2 into T 1. We would not say, for example, that the function of the ground is to hold up the rocks even though, in our technical sense, the ground contributes to the holding up of rocks. It would seem that out of the whole set of "contributing" cases, only a very restricted subset could be regarded as functions.
How may this subset be specified? We ordinarily attribute functions to two sorts of systems, artifacts and living things. We may consider first a simple artifact such as a cooking pan. We ascribe a function to the whole pan: cooking. Moreover, we also ascribe functions to parts and properties of the pan insofar as they contribute to its usefulness in cooking. For example, it is natural to think of the handle as providing a grip, of the rivets as fastening on the handle, and so on. In short, whenever we are prepared to acknowledge a single function F, we are also prepared to acknowledge a hierarchy of functions, with F at the top and the functions at each lower level contributing to all those above them.
The assignment of functions to living organisms proceeds on the same principle. There are two organic processes that are regarded as fundamental, the maintenance of life and reproduction. Alternatively, these two processes may be thought of as contributing to a single process, the maintenance of a species, which stands at the top of all functional hierarchies. The fundamental processes thus play a defining role in the identification of functions. The following schema lays down a necessary and sufficient condition of functional activity: F 1 is a function of A in S if and only if A contributes to F 1 in S ; and F 1 is identical with or contributes to F 2 in S, where F 2 is either a purpose for which the artifact S is designed or the process of maintenance of the species of which S is a member.
The concept of an artifact may be interpreted quite broadly in order to include not only things like cooking pans but also all cultural products, such as works of art, language, and legal institutions. It makes sense, for example, on the above analysis and on this interpretation of artifact, to ask "What is the function of Ophelia in Hamlet? " and "What is the function of verb inflections in Japanese?" The justification for regarding maintenance of the species as a fundamental function, serving a logical role in functional analysis, is examined below.
need for special concepts or patterns of analysis
The definition of functional activity offered above provides a way of interpreting ascriptions of functions without using explicitly teleological expressions. However, there is a sense in which many of the concepts that are employed in the ascription of functions are implicitly teleological. Consider, for example, the concept of an "escape reaction." It is applied to a great variety of animal movements, such as flying up, forming dense schools, withdrawing into burrows, jumping into water, and gathering under the mother. These diverse reactions probably have no relevant feature in common other than a functional one; they all, in the technical sense, contribute to the avoidance of death by predation. Such functional concepts are common in the theory of animal behavior, in all branches of natural history, in physiology, and indeed in everyday language. The terms that we most commonly use, for example, in describing machines are defined functionally.
The view that teleological language can be eliminated from the language of science may be true; again, the most difficult cases concern human agency. But the program of eliminating teleological expressions even from biological theory must involve more than the elimination of such terms as function, purpose, goal, and in order to. If there is any point in eliminating these terms, there is just as much point in eliminating all concepts that are defined functionally, for "The function of this movement is to escape from a predator" is equivalent in asserted content to "This movement is an escape reaction." It is obviously true that the movement in question can be described, without employing the term escape reaction, as a movement that contributes to the avoidance of a predator. But if we eliminate the term escape reaction, we have excised from the language the term that applies not only to this movement but to all the diverse movements, in a variety of taxonomic groups, that serve this function.
The ascription of functions, therefore, does not require either an explicit or an implicit teleological vocabulary. It should be recognized, however, that the elimination of implicitly teleological expressions (concepts that are defined functionally) would result in a language for biological theory that would bear very little resemblance to the existing language.
Moreover, the difference would not be superficial; the rejection of functional concepts would amount to the rejection of a powerful and fruitful conceptual scheme. Our picture of living organisms as organized functional hierarchies is an essential part of the theory of natural selection; it is the foundation of physiology and morphology; and it is the basis of the medical view of disease as derangement of function. It is the fruitfulness of this conceptual scheme, embodied in a network of connected functional concepts, that constitutes the justification for assigning to maintenance of the species its central logical role in the ascription of functions.
Relation between Ascriptions of Function and of Purpose
We have drawn a sharp distinction between functional activities, which contribute to a "fundamental" process, and purposive activities, which are persistent, flexible patterns of directively correlated behavior. It is clear, however, that function and purpose are closely connected—so closely, indeed, that many writers have failed to see the distinction. These connections may be described as follows:
(a ) Whenever we construct an artifact as an aid to our own purposive activities, we are willing to ascribe functions to the artifact and to its parts and properties.
(b ) Many but by no means all organic functions are served by purposive activities. For example, temperature regulation in the mammals involves directive correlation, whereas the excretion of urine does not.
(c ) Conversely, every organic mechanism that provides an organism with the means of purposive activity serves the function of maintenance of the species. This is an empirical fact. It does not mean, however, that each case of purposive activity, when it occurs, performs a function. A purposive activity that is ordinarily adaptive (functional under normal circumstances) can lead to disaster when the circumstances are abnormal. For example, the homing of a male moth on a female, directed by the attractant secreted by the female, is ordinarily both purposive and functional. But it can lead the moth to his death when the attractant is placed on a surface covered with an insecticide.
See also Braithwaite, Richard Bevan; Functionalism; Functionalism in Sociology; Nagel, Ernest; Organismic Biology; Perry, Ralph Barton; Speculative Systems of History; Teleological Argument for the Existence of God; Teleological Ethics.
Braithwaite, R. B. Scientific Explanation. Cambridge, U.K.: Cambridge University Press, 1953.
Braithwaite, R. B. "Teleological Explanations." PAS, n.s., 47 (1947): i–xx.
Hofstadter, A. "Objective Teleology." Journal of Philosophy 38 (2) (January 1941): 29–39.
Nagel, Ernest. "Teleological Explanation and Teleological Systems." In Readings in the Philosophy of Science, edited by H. Feigl and M. Brodbeck, 537–558. New York: Appleton-Century-Crofts, 1953. A revised and enlarged version of this article appears in Nagel's The Structure of Science, 401–428. New York: Harcourt Brace, 1961.
Perry, R. B. "A Behavioristic View of Purpose." Journal of Philosophy 18 (4) (February 1921): 85–105.
Russell, E. S. The Directiveness of Organic Activities. Cambridge, U.K.: Cambridge University Press, 1945.
Sommerhoff, George. Analytical Biology. London, 1950.
Tolman, E. C. Purposive Behavior in Animals and Men. New York: Century, 1932.
Morton Beckner (1967)
Teleology, from the Greek telos (purpose), is a term generally thought to have been coined by the German philosopher Christian Wolff in 1728. Teleology refers to the science of final causes. In Aristotle's philosophy, there were four sorts of causes, or principles for explaining the nature of things. One of these is the final cause, for the sake of which an object exists. Aristotle held that virtually all objects, especially organic objects, have a final cause. It is a principle inherent in them, which disposes them to realize a particular state, which can be seen as the purpose for their existence. It is closely related to the formal cause, which is the essential nature (the form ) of an object. For many objects, the final cause simply is the fullest realization of the formal cause. Aristotle saw organisms as striving to realize their true natures as they grew and developed.
The final cause of an acorn, for example, is a fully grown oak tree. The acorn is naturally disposed to become an oak tree. That is the proper realization of its nature, the reason it exists. The idea of final causality applies most obviously to organisms. It has two forms. One might be called part-whole teleology —the parts of an organism exist for the sake of the whole (the heart exists in order to pump blood around the body). The other might be called goal-oriented teleology —the purpose of a seed or embryo is to grow into a particular organic form. Aristotle implied that all objects act for a purpose or end, so that even rocks have an inherent purpose for existence, even if it just to be a good solid rock. Aristotle did not appeal to a God for this idea, but saw final causality and formal causality as a principle inherent in all existent objects.
When medieval philosophers in Judaism, Christianity, and Islam took over Aristotelian categories, they explicitly introduced a creator God as a being who gives all things their final causes, and that is itself the final cause of the entire universe, for the sake of which it exists. Thus, one of Thomas Aquinas's (c. 1225–1274) arguments for God is that, since all bodies tend to a goal, they must be directed to it by some being with awareness and intelligence, "and this we call God" (Summa Theologiae 1a, 2, 3). Aquinas includes the fact that bodies obey natural laws as a form of final causality. They do not act by accident, but obey the laws as if intended to do so, and this points to the fact that they are so intended.
A marked feature of post-sixteenth century science was its rejection of, or at least indifference to, any doctrine of final causes in nature. Laws of nature were seen as general principles of interaction between objects (perhaps ultimately between atoms), which have no purpose; they just happen to be (perhaps by some unknown mathematical necessity) the way they are. The last remnant of Aristotelian teleology was vitalism, the belief that at least organisms are actuated by some immaterial vital principle that explains their structure and development. Most biologists reject this notion as unnecessary mystification, and look for purely physical causes of organic structure and development.
The Design argument
In eighteenth-century Europe, a new form of design argument took shape that did not appeal to inherent final causes in things. Instead, it pointed to the way in which the parts of nature cooperate to produce apparently well-designed wholes. A general mechanism of nature is accepted, but that mechanism is seen as producing elegant and desirable states, conducive to the survival and flourishing of organisms, particularly human beings. Nature is a well-designed machine, and its ultimate purpose is the pleasure of conscious human beings. William Paley wrote A View of the Evidences of Christianity in 1794, and it became for many years the standard exposition of the design argument. It adduced a host of biological and natural facts to show that nature is an efficient process that realizes highly desirable ends, which shows that nature is designed and that a designer is therefore needed. This could be called the universal design argument, since it refers to the general structure of the universe and its laws. Paley also argued that there are many evidences of particular design in nature, from the fact that the eye is perfectly designed for vision to the fact that camels are specially constructed to store water in the desert.
David Hume's Dialogues Concerning Natural Religion, published posthumously in 1779, was a devastating critique of such design arguments, and he is generally felt to have refuted Paley's views fifteen years before they appeared. Immanuel Kant, in his Critique of Pure Reason (1781), wrote that the design argument was naturally convincing to all, but it was not logically compelling. In particular, it does not show the necessity for an all-perfect creator. According to Kant, there is a definite appearance of design in nature, but there could be another explanation for it.
That other explanation was provided by Charles Darwin's theory of descent with modification, or natural selection, in the Origin of Species (1859). This theory, later broadened into universal Darwinism by a number of philosophers, posits that multiple replication and random mutation of organisms, together with ruthless selection by environment, naturally leads over many generations to just the sort of improvements or adaptations that look as if they have been designed, though in fact the mechanism of repeated mutation and natural selection is sufficient to produce that appearance.
Teleology and evolution
To many it seems that teleology has at last been extruded from natural science, and from any reasonable account of the general structure of the universe. Others, however, think this is not the case. In 1928, the Cambridge philosopher F. R. Tennant published his Philosophical Theology, in which he gave an extended argument for a teleological view of evolution. In opposition to the Darwinian, or neo-Darwinian, view that mutation is random and undirected, he argued that one can discern a direction in the evolutionary process towards an increase of consciousness, intelligence, and intentional action. Individual mutations are random, in the sense that they are not all directed toward the improvement of the species. But they have an overall propensity, in conjunction with the supportive nature of the environment, to lead to the development of intelligent organisms like human beings. That the environment supports such developments is not an accident, but suggests that the whole cosmic system, in its general evolutionary structure, is well adapted to the production of conscious life forms.
There is, according to Tennant, probably not a particular teleology whereby camels are specially designed to live in deserts. But there is a general teleology whereby organisms that live in deserts continue to produce genetic mutations, some of which will eventually lead to the existence of water-storing organisms like camels. Tennant admits that all this could logically happen by chance, given the existence of laws governing genetic mutation and environmental change. But is it not a puzzle that these laws are just what they need to be to produce organisms like camels and human beings? Darwin himself apparently felt there was a puzzle, but he never solved it.
There would be no puzzle if humans were considered to have no greater value than specks of dust. But if humans are seen as immensely complex integrated structures (and the brain is the most complex structure known in the universe) that value their own existences and may even be of unique intrinsic dignity and value, then there is a puzzle. An evolutionary teleological argument will only work on two conditions—if the evolutionary process is an efficient way of producing its putative goal, and if that goal is indeed of great desirability, perhaps just what an intelligent designer would want to produce.
Darwinians may argue that the process is inefficient or cruel—there are too many mistakes and blind alleys. And they may argue that humans are not of unique value, except, naturally enough, to themselves. Tennant responds that the "mistakes" are necessary parts of a process in which freedom, and therefore some degree of indeterminacy, is an essential part. And the value of human persons lies in their possession of moral responsibility and the ability to relate to one another and to the creator in love.
Is this a scientific argument? It seems not, for the biological facts are not in dispute. It is an argument about how one evaluates organic existence and human personhood. One's attitude toward teleology depends upon evaluative judgments about whether the evolutionary process is "worth it," and about whether humans have a special dignity and moral status.
Belief in God is not necessary to a teleological view—that is, a view that there is a direction in the evolutionary process towards states of unique and unexpected value. One could be a humanist or a Marxist and hold such a teleological view. Many Marxists, for instance, and probably Karl Marx (1818–1883) himself, saw nature as progressively realizing its own inherent drive towards a free and creative society of persons, without the existence of any "external" or omniscient intelligence. If there were to be such an intelligence, it would be the final consequence of the cosmic process, not its precondition.
Among Christian thinkers, the paleontologist Pierre Teilhard de Chardin (1881–1955) has restated a Christian teleological view that owes much to both Darwin and Marx. According to Teilhard, the universe as a whole moves towards greater complexity and higher levels of consciousness. The emergence of human consciousness was a saltation in the process, by which the universe (or parts of it) became capable of conscious self-direction for the first time, so far as we know. The process will continue in the development on Earth of a noosphere, in which all individual consciousnesses become progressively unified. The final culmination will be the Omega Point, when the whole material universe will be unified in the life of one omniscient and wholly self-directing spirit. However, Teilhard posits that this Omega Point, being beyond historical time, has in fact always existed as the causal basis of the whole historical process. It is, in fact, God, which, though timelessly complete, realizes itself progressively in cosmic time.
This grand cosmic vision takes evolutionary theory back to its philosophical origins in the work of George Wilhelm Friedrich Hegel (1770–1831), for whom evolution was a gradual self-realization of absolute spirit. This form of evolutionary theory is cosmically optimistic, and committed to a teleological view of the universe as directed towards its final consummation, and perhaps transformation, in the spiritual reality of God. For many, however, this is both too optimistic and too grandiose a vision for the available evidence, which seems to them much more ambiguous in its indications of continued improvement towards a final goal. Just as the dinosaurs were wiped out, so too all life on Earth could be wiped out by some catastrophe, which would eliminate any possibility of purpose in evolution.
Teilhard considered, however, that the cosmic purpose could be completed beyond this physical space-time, in a new environment created by God. So one can hold that there is a purpose in evolution—to produce conscious beings capable of relating to God. But the real final goal is eschatological; it lies in the fulfillment of persons in God beyond the present space-time. This view is clearly not open to empirical testing, though questions of whether persons can survive the death of their physical bodies are relevant to its plausibility.
Teleology in modern thought
Within modern science, there are those, like Michael Behe and William Dembski, who argue that there is still a need to appeal to teleology. They hold that small incremental mutations cannot account for the existence of organs like the eye, which need to exist as a whole in order to function at all. The so-called Intelligent Design argument is about the adequacy of Darwinian explanations to account for all features of organic life.
More widespread, however, are arguments of cosmologists like Paul Davies that the amount of "fine-tuning" of physical constants and laws that is required to produce conscious life in a physical universe is much too great to be due to chance. Some physicists are so impressed by the complex interrelation of physical laws needed to produce life that they think some sort of intelligence must underlie the universe. For most, this intelligence is not a God like that of orthodox religion. It is more like a vast intelligence that is not morally concerned with the lives and happiness of organisms.
Other physicists, like Steven Weinberg, think the hypothesis of an intelligence is superfluous. They would like to see the derivation of the laws of this universe as necessarily following from some impersonal and invariant superset of laws. The supposition that such a superset is necessarily there, however, seems to posit a sort of necessity that science cannot establish. To the religious believer, that necessity might well lie in the intentions of a creator God, who has an ultimate purpose in creating it.
On a less speculative level, there remains the important question, harking back to Aristotle, of whether some sort of teleological, purposive explanation is needed for a complete account of observed reality. In modern science, nomological explanation (in terms of general laws, without reference to purpose) is firmly established as a fruitful explanatory principle. But it is not at all clear whether it is adequate for explaining the facts of human consciousness and social life. Many would argue that explanation in terms of purpose or intention is needed to explain why humans act as they do. After all, they often do things because they intend to. They do seem to have purposes. Others, however, hope to discover nomological forms of explanation that will cover all these factors—probably by investigating sorts of brain activity. The question remains: Is there a teleology, at least in human affairs, that does not reduce to nomological explanation?
Again, this question does not necessarily involve questions of religious belief. But if teleological explanation were found to be necessary for parts of the universe, this might keep open the genuine question of whether the universe has a purpose or goal. In that case, it will be a compelling thought to many that there must be a God, something like a cosmic mind by which such a purpose could be formulated and implemented.
The question of whether teleology is a basic feature of the universe is unresolved. It looks as if such ultimate "scientific" questions go beyond the realms of verifiable fact to questions of the ultimate nature of reality, questions traditionally regarded as philosophical in nature. Consideration of scientific facts is relevant to such questions, but in the end the interpretation of the facts seems to depend on evaluations and on basic attitudes to a materialistic philosophy, both of which go beyond the scientific evidence.
See also Aristotle; Causation; Christianity, History of Science and Religion; Darwin, Charles; Design Argument; Eschatology; Freedom; God; Hume, David; Intelligent Design; Islam, Contemporary Issues in Science and Religion; Judaism, Contemporary Issues in Science and Religion; Kant, Immanuel; Teilhard de Chardin, Pierre; Thomas Aquinas
davies, paul. the mind of god. new york: simon and schuster, 1992.
hume, david. dialogues concerning natural religion (1799). in dialogues concerning natural religion and the natural history of religion, ed. j. c. a. gaskin. oxford: oxford university press, 1998.
kant, immanuel. critique of pure reason (1781), trans. norman kemp smith. london: macmillan, 1978.
paley, william. a view of the evidences of christianity (1794).
polkinghorne, john. science and creation: the search for understanding. london: spck, 1988.
taylor, richard. action and purpose. englewood cliffs, n.j.: prentice-hall, 1966.
teilhard de chardin, pierre. the phenomenon of man, trans. bernard wall. new york: harper, 1959.
tennant, f. r. philosophical theology. cambridge, uk: cambridge university press, 1928.
ward, keith. god, chance, and necessity. oxford: oneworld press, 1996.
ward, keith. god, faith and the new millennium. oxford: oneworld press, 1998.
The term teleology (from the Greek telos, meaning end ) refers broadly to end-directedness, the idea that some things exist, have certain traits, or do certain things for the sake of some end. Many familiar cases of teleology are directly psychological, as when someone goes to the store in order to get milk. Here the behavior is intentional and the end is the object of the agent’s intention. In other cases, involving artifacts, psychology plays an indirect but equally crucial role through design and use. For example, a spark plug exists, is present in the engine, and sparks at a certain point in the combustion cycle for the sake of igniting the fuel. Though such objects have no intentions of their own, they have proper functions—things they may be said to do for the sake of some end, as opposed to other things they just happen to do (such as the spark plug’s making a noise when it sparks).
The most interesting questions about teleology concern living things. We commonly apply teleological concepts to the parts and features of organisms. The heart, for example, is said to have the proper function of pumping the blood, which in turn occurs for the sake of blood circulation and the biological ends of nutrient distribution and waste removal; pumping the blood is what the heart is for in the organism, as opposed to other things it does merely as side-effects (such as making a lub-dub noise). This is a teleological claim analogous to claims about artifacts, and it licenses similar function-based evaluations: Just as a spark plug that does not fire under the right conditions is a defective spark plug, so too a heart that fails to pump in certain ways under the right conditions is a defective heart. Similar points may be made even about the parts and features of plants—for example, a color pattern on a flower may have the biological function of attracting pollinating insects, this being what that adaptation is for in the life of such plants. The question is whether it is legitimate to apply teleological concepts to the natural world in this way and, if so, how this application is to be understood.
It might at first seem that all uses of teleological concepts in biology are ruled out by neo-Darwinian evolutionary theory. Certainly the theory does reject the idea that the process of evolution is teleological. It is another question, however, whether the products of evolution—the parts and features of evolved organisms—might stand in teleological relations. In fact, many philosophers of biology agree that natural selection itself provides a basis for teleological judgments about adaptations and their relevant effects. This is because natural selection mimics design in an important respect. A designer makes a spark plug the way it is and puts it in the engine so that it will spark and ignite the fuel, and this means that these effects partly explain (via the designer’s intentions) the presence of the spark plug in the engine, setting them apart as proper functions and ends served by the spark plug. Natural selection does not, of course, deliberately do anything or act with any foresight, but it still yields a similar relation between an adaptation and certain effects it has. In the case of the evolved color pattern, for example, the effect of attracting pollinating insects partly explains (via natural selection) the trait’s coming to be a standard feature of the evolved species, setting this effect apart as specially relevant to the formation and life of this species of plant. Many have argued that this provides a basis for sensible talk of proper functions and ends in connection with biological adaptations.
The above approach sharply contrasts with any approach that seeks to explain teleological facts about organisms by attributing teleology to the processes by which species are formed. A common form of creation-ism, for example, posits direct creation of each species by a divinity, giving organisms a design-based teleology analogous to that of artifacts. Intelligent design theory, by contrast, may accept evolution and common ancestry, but still posits supernatural direction of evolutionary processes on the grounds that neo-Darwinism alone “cannot possibly” explain the evolution of certain complex structures. Proponents of intelligent design argue, for example, that providence guides the genetic mutations upon which natural selection acts.
While the doctrine of special creation has been discredited by a wealth of empirical evidence for evolution, intelligent design theory is trickier. Because there is no way to demonstrate the absence of divine intervention in historical processes, the theory can never be disproved. For this very reason, however, it also falls plainly outside the scope of science. The biological work cited by proponents of intelligent design would remain within science if it were used simply to point out puzzles and shape scientific research projects to try to solve them. But by treating the puzzles as grounds for embracing supernatural hypotheses, intelligent design becomes a religious alternative to the scientific enterprise rather than a scientific alternative to neo-Darwinism, as its proponents often claim it to be when advocating its inclusion in public school curricula.
Historically, the track record for the God-of-the-gaps approach—that is, appeals to the supernatural to explain whatever is currently difficult to explain scientifically—has not been impressive, as claims about what science cannot possibly explain are steadily overturned. Still, despite its not being science, intelligent design theory could of course turn out to be true. If it did, it would provide for a partially design-based biological teleology and a purposive direction for evolution itself. Strictly speaking, theists could have this general result even without embracing intelligent design at the level of natural processes. They could, for example, posit divine influence in the shaping of the background laws, allowing for a more general divine purpose behind creation without the micromanagement of evolution. It is worth noting that at least for part of his career Darwin himself was not averse to that idea, and similar claims have been advanced outside of biology as well. Some have argued, for example, that a divine intelligence is necessary to explain the highly unlikely confluence of “finely tuned” physical laws, physical constants, and cosmological conditions that was crucial for the eventual emergence and evolution of life in the universe. According to such a view, which is not logically inconsistent with neo-Darwinian evolutionary theory, there could be a very general design-based teleology in addition to the teleology rooted in natural selection.
SEE ALSO Creationism; Darwin, Charles; Hegel, Georg Wilhelm Friedrich; Idealism
Allen, Colin, Mark Bekoff, and George Lauder, eds. 1988. Nature’s Purposes: Analyses of Function and Design in Biology. Cambridge, MA: MIT Press.
FitzPatrick, William. 2000. Teleology and the Norms of Nature. New York: Garland Publishers.
Neander, Karen. 1991. Functions as Selected Effects: The Conceptual Analyst’s Defense. Philosophy of Science 58: 168–184.
Orr, H. Allen. 2005. Devolution: Why Intelligent Design Isn’t. New Yorker, May 30: 40–52.
Wright, Larry. 1976. Teleological Explanations: An Etiological Analysis of Goals and Functions. Berkeley: University of California Press.
William J. FitzPatrick
tel·e·ol·o·gy / ˌtelēˈäləjē; ˌtēlē-/ • n. (pl. -gies) Philos. the explanation of phenomena by the purpose they serve rather than by postulated causes. ∎ Theol. the doctrine of design and purpose in the material world.DERIVATIVES: tel·e·o·log·ic / -əˈläjik/ adj.tel·e·o·log·i·cal / -əˈläjikəl/ adj.tel·e·o·log·i·cal·ly / -əˈläjik(ə)lē/ adv.tel·e·ol·o·gism / -ˌjizəm/ n.tel·e·ol·o·gist / -jist/ n.