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Darwin-L Message Log 1:153 (September 1993)
Academic Discussion on the History and Theory of the Historical Sciences
This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.
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<1:153>From junger@samsara.law.cwru.edu Thu Sep 16 16:13:18 1993 Date: Thu, 16 Sep 93 17:10:14 EDT From: junger@samsara.law.cwru.edu (Peter D. Junger) To: darwin-l@ukanaix.cc.ukans.edu Subject: A Selection of Passages from Ernst Mayr--for discussion purposes only Here are some extracts from: Ernst Mayr, TOWARD A NEW PHILOSOPHY OF BIOLOGY, Observations of an Evolutionist. Harvard University Press, Cambridge: 1988. I find much of this objectionable, but shall not raise my objections at this time, other than to say that in Mayr it seems that his Physics envy has become fixated upon the fact that almost all "philosophies of science" are, in fact, philosophies of physics. ---------------------------------------------------------------------- >From Essay 2, "Cause and Effect in Biology" {*29} . . . . _The Problem of Teleology_ No discussion of causality is complete which does not come to grips with the problem of teleology. This problem had its beginning with Aristotle's classification of causes, one of the categories being "final" causes. This category is based on the observation of the orderly and purposive development of the individual from the egg to the "final" state of the adult. Final cause has been defined as "the cause responsible for the orderly reaching of a preconceived ultimate goal." All goal-seeking behavior has been classified as "teleological," but so have many other phenomena that are not necessarily goal-seeking in nature. Aristotelian scholars have rightly emphasized that Aristotle--by training and interest--was first and foremost a biologist, and that it was his preoccupation with biological phenomena which dominated his ideas on causes and induced him to postulate final causes in addition to the material, formal, and efficient causes. Thinkers from Aristotle to the present have been challenged by the apparent contradiction between a mechanistic interpretation of natural processes and the seemingly purposive sequence of events in organic growth, reproduction, and animal behavior. Such a rational thinker as Bernard (1885) has stated the paradox in these words: There is, so to speak, a preestablished design of each being and of each organ of such a kind that each phenomenon by itself depends upon the general forces of nature, but when taken in connection with the others it {*30} seems directed by some invisible guide on the road it follows and led to the place it occupies. We admit that the life phenomena are attached to physicochemical manifestations, but it is true that the essential is not explained thereby; for no fortuitous coming together of physicochemical phenomena constructs each organism after a plan and a fixed design (which are foreseen in advance) and arouses the admirable subordination and harmonious agreement of the acts of life . . . Determinism can never be [anything] but physicochemical determinism. The vital force and life belong to the metaphysical world. What is the _x_, this seemingly purposive agent, this "vital force," in organic phenomena? It is only in our lifetime that explanations have been advanced which deal adequately with this paradox. The many dualistic, finalistic, and vitalistic philosophies of the past merely replaced the unknown _x_ by a different unknown _y_ or _z_, for calling an unknown factor _entelechia_ or _e'lan vital_ is not an explanation. I shall not waste time showing how wrong most of these past attempts were. Even though some of the underlying observations of these conceptual schemes are quite correct, the supernaturalistic conclusions drawn from these observations are altogether misleading. Where, then, is it legitimate to speak of purpose and purposiveness in nature, and where it is [_sic_] not? To this question we can now give a firm and unambiguous answer. An individual who--to use the language of the computer--has been "programmed" can act purposefully. Historical processes, however, _cannot_ act purposefully. A bird that starts its migration, an insect that selects its host plant, an animal that avoids a predator, a male that displays to a female--they all act purposefully because they have been programmed to do so. When I speak of the programmed "individual," I do so in a broad sense. A programmed computer itself is an "individual" in this sense, but so is, doing reproduction, a pair of birds whose instinctive and learned actions and interactions obey, so to speak, a single program. The completely individualistic and yet also species-specific DNA program of every zygote (fertilized egg cell), which controls the development of the central and peripheral nervous systems, of the sense organs, of the hormones, of physiology and morphology, is the _program_ for the behavior computer of this individual. Natural selection does its best to favor the production of programs guaranteeing behavior that increases fitness. A behavior program that guarantees instantaneous correct reaction to a potential food source, to a potential enemy, or to a potential mate will certainly give greater fitness {*31} in the Darwinian sense than a program that lacks these properties. Again, a behavior program that allows for appropriate learning and the improvement of behavior reactions by various types of feedback gives greater likelihood of survival that a program that lacks these properties. The purposive action of an individual, insofar as it is based on the properties of its genetic code, therefore is no more nor less purposive than the actions of a computer that has been programmed to respond appropriately to various inputs. It is, if I may say so, a purely mechanistic purposiveness. We biologists have long felt that it is ambiguous to designate such programmed, goal-directed behavior "teleological," because the word _teleological_ has also been used in a very different sense, for the final stage in evolutionary adaptive processes (see Essay 3). The development or behavior of an individual is purposive; natural selection is definitely not. When MacLeod (1957) stated, "What is most challenging about Darwin, however, is his re-introduction of purpose into the natural world," he chose the wrong word. The word _purpose_ is singularly inapplicable to evolutionary change, which is, after all, what Darwin was considering. If an organism is well adapted, if it shows superior fitness, this is not due to any purpose of its ancestors or of an outside agency, such as "Nature" or "God," that created a superior design or plan. Darwin "has swept out such finalistic teleology by the front door," as Simpson (1960) has rightly stated. We can summarize this discussion by stating that there is no conflict between causality and teleonomy, but that scientific biology has not found any evidence that would support teleology in the sense of various vitalistic or finalistic theories (Simpson 1960; 1950; Koch 1957). All the so-called teleological systems which Nagel discusses (1961) are actually illustrations of teleonomy. ----------------------------------------------------------------------- >From Essay 3, "The Multiple Meanings of Teleological" {*39} _Traditional Objections to the Use of Teleological Language Criticism of the use of teleological language is traditionally based on one or several of the following objections. In order to be acceptable teleological language must be immune to these objections. {*40} _(1) Teleological statements and explanations imply the endorsement of unverifiable theological or metaphysical doctrines in science._ This criticism was indeed valid in former times . . . . Contemporary philosophers reject such teleology almost unanimously. Likewise, the employment of teleological language among modern biologists does not imply adoption of such metaphysical concepts (see below). _(2) The belief that acceptance of explanations for biological phenomena that are not equally applicable to inanimate nature constitutes rejection of a physicochemical explanation._ Ever since the age of Galileo and Newton it has been the endeavor of the "natural scientists" to explain everything in nature in terms of the laws of physics. To accept special explanations for teleological phenomena in living organisms implied for these critics a capitulation to mysticism and a belief in the supernatural. They ignored the fact that nothing exists in inanimate nature (except for man-made machines) which corresponds to DNA programs or to goal-directed activities. As a matter fact, the acceptance of a teleonomic explanation (see below) is in no way in conflict with the laws of physics and chemistry. It is neither in opposition to a causal interpretation, nor does it imply an acceptance of supernatural forces in any way whatsoever. _(3) The assumption that future goals were the cause of current events seemed in complete conflict with any concepts of causality._ Braithwaite (1954) stated the conflict as follows: "In a [normal] causal explanation the explicandum is explained in terms of a cause which either precedes it or is simultaneous with it; in a teleological explanation the explicandum is explained as being causally related either to a particular goal in the future or to a biological end which is as much future as present or past." This is why some logicians up to the present distinguish between causal explanations and teleological explanations. _(4) Teleological language seemed to represent objectionable anthropomorphism._ The use of terms like _purposive_ or _goal-directed_ seemed to imply the transfer of human qualities such as intent, purpose, planning, deliberation, or consciousness, to organic structures and to subhuman forms of life. {*41} Intentional, purposeful human behavior is, almost by definition, teleological. Yet I shall exclude it from further discussion because use of the words _intentional_ or _consciously premeditated_, which are usually employed in connection with such behavior, runs the risk of getting us involved in complex controversies over psychological theory, even though much of human behavior does not differ in kind from animal behavior. The latter, although usually described in terms of stimulus and response, is also highly "intentional," as when a predator stalks his prey or when the prey flees from the pursuing predator. Yet, seemingly "purposive," that is, goal-directed behavior in animals can be discussed and analyzed in operationally definable terms, without recourse to anthropomorphic terms like _intentional_ or _consciously_. . . . . The teleological dilemma, then, consists in the fact that numerous and seemingly weighty objections against the use of teleological language have been raised by various critics, and yet biologists have insisted that they would lose a great deal, methodologically and heuristically, if they were prevented from using such language. It is my endeavor to resolve this dilemma by a new analysis, and particularly by a new classification of the various phenomena that have been traditionally designated as teleological. . . . . {*44} . . . . _SEEMINGLY OR GENUINELY GOAL-DIRECTED PROCESSES_ Nature (organic and inanimate) abounds in processes and activities that lead to an end. Some authors seem to believe that all such terminating processes are of one kind and "finalistic" in the same manner and to the same degree. Taylor (1950), for instance, if I understand him correctly, claims that all forms of active behavior are of the same kind and that there is no fundamental difference between one kind of movement or there is no fundamental difference between one kind of movement or purposive action and any other. Waddington (1968) gives a definition of his term _quasi-finalistic_ as requiring "that the end state of the process is determined by its properties at the beginning." Further study indicates, however, that the class of end-directed processes is composed of two entirely different kinds of phenomena. These two types of phenomena may be characterized as follows: _Teleomatic processes in inanimate nature._ Many movements of inanimate objects as well as physicochemical processes are the simple consequences of natural laws. For instance, gravity provides the end-state for a rock which I drop into a well. It will reach its end-state when it has come to rest on the bottom. A red-hot piece of iron reaches its end-state when its temperature and that of its environment are equal. All objects of the physical world are endowed with the capacity to change their state, and these changes follow natural laws. They are end-directed only in a passive, automatic way, regulated by external forces or conditions. Since the end-state of such inanimate objects is automatically achieved, such changes might be designated as _teleomatic_. All teleomatic processes come to an end when the potential is used up (as in the cooling of a heated piece of iron) or when the process is stopped by encountering an external impediment (as a falling stone hitting the ground). Teleomatic processes simply follow natural laws, i.e. lead to a result consequential to concomitant physical forces, and the reaching of their end-state is not controlled by a built-in program. The law of gravity and the second law of thermodynamics are among the natural laws which most frequently govern teleomatic processes. _Teleonomic_ processes in living nature._ Seemingly goal -directed behavior by organisms is of an entirely different nature from teleomatic processes. {*45} Goal-directed _behavior_ (in the widest sense of this word) is extremely widespread in the organic world; for instance, most activity connected with migration, food-getting, courtship, ontogeny, and all phases of reproduction is characterized by such goal orientation. The occurrence of goal-directed processes is perhaps the most characteristic feature of the world of living organisms. For the last 15 years or so the term _teleonomic_ has been used increasingly often for goal-directed processes in organisms. I proposed in 1961 the following definition for this term: :It would seem useful to restrict the term teleonomic rigidly to systems operating on the basis of a program, a code of information" (Mayr 1961) Although I used the term _system_ in this definition, I have since become convinced that it permits a better operational definition to consider certain activities, processes (like growth), and active behaviors as the most characteristic illustrations of teleonomic phenomena. I therefore modify my definition, as follows: _A teleonomic process or behavior is one which owes its goal-directedness to the operation of a program._ The term teleonomic implies goal direction. This, in turn, implies a dynamic process rather than a static condition, as represented by a system. The combination of teleonomic with the term system is, thus, rather incongruent (see below). All teleonomic behavior is characterized by two components. It is guided by a "program," and it depends on the existence of some end, goal, or terminus which is foreseen in the program that regulates the behavior. This endpoint might be a structure, a physiological function, the attainment of a new geographical position, or a "consummatory" (Craig 1918) act in behavior. Each particular program is the result of natural selection, constantly adjusted by the selective value of the achieved end-point. My definition of _teleonomic_ has been labeled by Hull (1974) as a "historical definition." Such a designation is rather misleading. Although the genetic program (as well as its individually acquired components) originated in the past, this history is completely irrelevant for the functional analysis of a [sic] given teleonomic processes. For this it is entirely sufficient to know that a "program" exists which is causally responsible for the teleonomic nature of a goal-directed process. Whether this program had originated through a lucky macromutation (as Richard Goldschmidt had conceived possible) or through a slow process of gradual selection, or even through individual learning or conditioning as in open programs, is quite immaterial for the classification of a process as "teleonomic." On the other {*46} hand, a process that does not have a programmed end does not qualify to be designated as teleonomic (see below for a discussion of the concept _program_). All teleonomic processes are facilitated by specifically selected executive structures. The fleeing of a deer form a predatory carnivore is facilitated by the existence of superlative sense organs and the proper development of muscles and other components of the locomotory apparatus. The proper performing of teleonomic processes at the molecular level is made possible by highly specific properties of complex macromolecules. It would stultify the definition of _teleonomic_ if the appropriateness of these facilitating executive structures were made part of it. On the other hand, it is in the nature of a teleonomic program that it does not induce a simple unfolding of some completely preformed gestalt, but that it always controls a more or less complex process which must allow for internal and external disturbances. Teleonomic processes during ontogenetic development, for instance, are constantly in danger of being derailed even if only temporarily. There exist innumerable feedback devices to prevent this or to correct it. Waddington (1957) has quite rightly called attention to the frequency and importance of such homeostatic devices which virtually guarantee the appropriate canalization of development. We owe a great debt of gratitude to Rjosenblueth et al. (1943) for their endeavor to find a new solution for the explanation of teleological phenomena in organisms. They correctly identified two aspects of such phenomena: (10) that they are seemingly purposeful, being directed toward a goal, and (2) that they consist of active behavior. The background of these authors was in the newly developing field of cybernetics, and it is only natural that they should have stressed the fact that goal-directed behavior is characterized by mechanisms which correct errors committed during the goal seeking. They considered the negative feedback loops of such behavior as its most characteristic aspect and stated "teleological behavior, yet it misses the crucial point: _The truly characteristic aspect of goal-seeking behavior is not that mechanisms exist which improve the precision with which a goal is reached, but rather that mechanisms exist which initiate, i.e. "cause" this goal-seeking behavior. It is not the thermostat which determines the temperature of a house, but the person who set the thermostat. It is not the torpedo which determines toward what ship it will be shot and at what time, but the naval officer who releases the torpedo. Negative feedback only improves the precision of goal-seeking, but does not determine it. {*47} Feedback devices are only executive mechanisms that operate during the translation of a program. Therefore it places the emphasis on the wrong point to define teleonomic processes in terms of the presence of feedback devices. They are mediators of the program, but as far as the basic principle of goal achievement is concerned, they are of minor consequence. . . . . Peter D. Junger Case Western Reserve University Law School, Cleveland, OH Internet: JUNGER@SAMSARA.LAW.CWRU.Edu -- Bitnet: JUNGER@CWRU
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