Teleology (from Greek words telos, “end,” and logos, “reason, discourse”) is the study of processes in nature as they are driven by their ends, goals, and purposes. This is diametrically opposed to a mechanistic explanation based only on cause-effect sequences in time series.
Teleological thinking was natural for mythical, anthropomorphic explanations of nature. A tradition of nonmythical teleological explanation starts with Aristotle’s concept of causa finalis, thanks to his extraordinary influence on natural sciences in the Middle Ages, although teleological concepts of nature can be found in pre-Socratic philosophers and Plato’s dialogues. Aristotle included the end as an additional and the most important cause of all natural processes. It presuppose in general that a final state of affairs in future explains or predetermines the movement from previous states to final ones.
Teleology was never too far from theology. Theologists in the Middle Ages identified Aristotelian ends and goals in the universe with purposes and intentions—and those with God’s will. The Aristotelian concept of causa finalis, after being hybridized with Plato’s concept of eternal Forms and cosmic Demiurge, started to be a common explanation of a complex design of living beings, their functionality, and their goal-oriented behavior Argument from design became one of the most important theological arguments for the existence of God. This argument turned out to be even more important with the rise of modern science in the 16th and 17th centuries, when the Aristotelian concept of causa finalis was expelled from nonliving nature.
Modern study of Aristotle’s philosophy revealed that his concept of teleology traditionally has been misinterpreted. In contrast with general belief, Aristotle did not think that the natural motions and changes of nonliving objects achieved a goal in the same way that developing organisms do. Natural processes of non-living objects, like stones falling down to the center of the Earth, are not (in Aristotle’s words) “for the sake of” anything, in contrast to organismal development which is, in fact, for the sake of a mature individual.
Specific philosophical attempts to reconcile the cause-effect mechanistics of Newtonian physics ( nexus effectivus) with obvious teleological causality ( nexus finalis) present in living beings were made by Kant (1724-1804) in his Critique of Judgment. Kant saw a principal difference between man-made artifacts on one hand and organisms on the other hand, similar to Aristotle. In artificial things, like a clock, all parts are put together to act as an integral whole; each part exists for the other parts, but not thanks to them, as in living beings. A constitutive force of the clock is outside of the clock, in a human being who is able to act in accord with the idea of the whole. As he pointed out, one cogwheel does not create another one and clocks do not create other clocks; they are not able to replace missing parts by themselves, nor are they able to repair themselves.
It is important to keep in mind that Kant’s reasoning on finality was done within the framework of his transcendental philosophy, from which it follows that teleology is a methodological approach rather than an ontological doctrine. We not only can (despite the mechanical cause-effect causality of physics) but we must think of organisms as directed by their own natural goals, and we have to keep in mind that these goals are not analogous to human intentions (“purposiveness without purpose”). They are domain-specific principles ( principia domestica) of natural science. This is why Kant is so critical of introducing the concept of God to natural science in order to explain teleogy in nature, and then later to use natural teleology as an argument for God’s existence.
Kant hoped that someday a scientist like Newton would be born who was able to explain even very simple teleological phenomena, like the production of a stem of grass, from natural laws without any need to use the idea of an intentional purpose. His kind of scientist appeared a half century later, and his name was Charles Darwin. Darwin, in his work The Origin of Species, came up with a radically new scientific explanation of teleological phenomena in the living world. According to his theory, functional designs and behaviors of organisms are not products of a divine designer, as suggested by the British theologian William Paley in his Natural Theology (1802), but adaptations to environment, outcomes of spontaneous evolutionary process based on a combination of genetic changes and natural selection. Both genetic changes and natural selection are, in principle, not goal-oriented natural mechanisms. Genetic changes are random with respect to the direction of adaptation; they do not respond to the needs of the organism for better adaptation (at the time, neo-Lamarckian inheritance of acquired characteristics and directed mutations were not confirmed). Although many evolutionary histories seem to be goal-directed lineages (for example, the evolution of the horse), evolutionary mechanisms are not providential—neither mutations nor natural selection has a purpose or goal.
The impersonal, nonpurposive, mechanistic nature of Darwinian evolutionary theory has been under strong criticism since it was formulated by Darwin in the middle of the 19th century, first by various so-called vitalists in the late 19th century and early 20th century who tried to understand the teleologic character of individual development. They refused to reduce life to physicochemical mechanisms, and they argued for life-specific principles. One of the most influential was German embryologist and philosopher Hans Driesch (1967-1941), with his neo-Aristotelian concept of entelechy. According to him, entelechy is an acting force in the embryo working towards developmental ends. Another example is French philosopher Henri Bergson (1859-1941) and his concept of a mystical live force, elan vital.
Following the rapid rise in the second half of the 20th century of modern biology based on biochemistry, and later on a molecular approach, almost all biologists rejected the concept of a natural force specific only to living things that does not obey physical and chemical laws. On the other hand, in nonscientific circles, opposition to the Darwinian explanation of life’s complexity remains and recently reappeared with the Intelligent Design movement. The main claim the movement is that it follows from empirical evidence itself that Darwinism is not a correct and scientific theory because it is not able to give a fully satisfactory explanation of the adaptive complexity of life. Therefore, it is necessary to suggest the existence of an intelligent designer—a new, not-yet-known, goal-oriented natural force—as a scientific alternative to Darwinism. However, the vast majority of biologists regard the Intelligent Design concept as pseudoscience.
- Dawkins, R. (1986). The blind watchmaker. New York: W. W. Norton.
- Gotthelf, A. (1987). Aristotle’s conception of final causality. In A. Gotthelf & J. G. Lennox (Eds.), Philosophical issues in Aristotle’s biology (pp. 204-242). Cambridge: Cambridge University Press.
- Mayr, E. (1988). The multiple meaning of teleological. In Toward a new philosophy of biology (pp. 38-66). Cambridge, MA: Harvard University Press.