The teleological argument (from ), also known as physico-theological argument, argument from design, or intelligent design argument, is a rational argument for the existence of God or, more generally, that complex functionality in the natural world, which looks designed, is evidence of an intelligent creator. The earliest recorded versions of this argument are associated with Socrates in ancient Greece, although it has been argued that he was taking up an older argument. Later, Plato and Aristotle developed complex approaches to the proposal that the cosmos has an intelligent cause, but it was the Stoics during the Roman era who, under their influence, "developed the battery of creationist arguments broadly known under the label 'The Argument from Design'".
Since the Roman era, various versions of the teleological argument have been associated with the Abrahamic religions. In the Middle Ages, Islamic theologians such as Al-Ghazali used the argument, although it was rejected as unnecessary by Quranic literalists, and as unconvincing by many Islamic philosophers. Later, the teleological argument was accepted by Saint Thomas Aquinas, and included as the fifth of his "Five Ways" of proving the existence of God. In early modern England, clergymen such as William Turner and John Ray were well-known proponents. In the early 18th century, William Derham published his Physico-Theology, which gave his "demonstration of the being and attributes of God from his works of creation". Later, William Paley, in his 1802 Natural Theology or Evidences of the Existence and Attributes of the Deity published a prominent presentation of the design argument with his version of the watchmaker analogy and the first use of the phrase "argument from design".
From its beginning, there have been numerous criticisms of the different versions of the teleological argument. Some have been written as responses to criticisms of non-teleological natural science which are associated with it. Especially important were the general logical arguments presented by David Hume in his Dialogues Concerning Natural Religion, published in 1779, and the explanation of biological complexity given in Charles Darwin's Origin of Species, published in 1859. Since the 1960s, Paley's arguments have been influential in the development of a creation science movement which used phrases such as "design by an intelligent designer", and after 1987 this was rebranded as "intelligent design", promoted by the intelligent design movement which refers to an intelligent designer. Both movements have used the teleological argument to argue against the modern scientific understanding of evolution, and to claim that supernatural explanations should be given equal validity in the public school science curriculum. Religious thinkers in Judaism, Hinduism, Confucianism, Islam and Christianity also developed versions of the teleological argument. Later, variants on the argument from design were produced in Western philosophy and by Christian fundamentalism. Contemporary defenders of the teleological argument are mainly Christians, for example Richard Swinburne and John Lennox.
Classical philosophy
Socrates and the pre-Socratics
thumb|upright|Plato and [[Aristotle, depicted here in The School of Athens, both developed philosophical arguments addressing the universe's apparent order (logos).]]
The argument from intelligent design appears to have begun with Socrates, although the concept of a cosmic intelligence is older and David Sedley has argued that Socrates was developing an older idea, citing Anaxagoras of Clazomenae, born about 500 BC, as a possible earlier proponent. Amongst Pre-Socratic philosophers before Anaxagoras, other philosophers had proposed a similar intelligent ordering principle causing life and the rotation of the heavens. For example Empedocles, like Hesiod much earlier, described cosmic order and living things as caused by a cosmic version of love, and Pythagoras and Heraclitus attributed the cosmos with "reason" (logos). In his Philebus 28c Plato has Socrates speak of this as a tradition, saying that "all philosophers agree—whereby they really exalt themselves—that mind (nous) is king of heaven and earth. Perhaps they are right." He later states that the ensuing discussion "confirms the utterances of those who declared of old that mind (nous) always rules the universe."
Xenophon's report in his Memorabilia might be the earliest clear account of an argument that there is evidence in nature of intelligent design. The word traditionally translated and discussed as "design" is gnōmē and Socrates is reported by Xenophon to have pressed doubting young men to look at things in the market, and consider whether they could tell which things showed evidence of gnōmē, and which seemed more to be by blind chance, and then to compare this to nature and consider whether it could be by blind chance. In Plato's Phaedo, Socrates is made to say just before dying that his discovery of Anaxagoras' concept of a cosmic nous as the cause of the order of things, was an important turning point for him. But he also expressed disagreement with Anaxagoras' understanding of the implications of his own doctrine, because of Anaxagoras' materialist understanding of causation. Socrates complained that Anaxagoras restricted the work of the cosmic nous to the beginning, as if it were uninterested and all events since then just happened because of causes like air and water. Socrates, on the other hand, apparently insisted that the demiurge must be "loving," particularly concerning humanity. In this desire to go beyond Anaxagoras and make the cosmic nous a more active manager, Socrates was apparently preceded by Diogenes of Apollonia.
Plato and Aristotle
Plato's Timaeus is presented as a description of someone who is explaining a "likely story" in the form of a myth, and so throughout history commentators have disagreed about which elements of the myth can be seen as the position of Plato.
Aristotle, Plato's student and friend (c. 384 – 322 BC), continued the Socratic tradition of criticising natural scientists such as Democritus who sought (as in modern science) to explain everything in terms of matter and chance motion. He was very influential in the future development of classical creationism, but was not a straightforward "creationist" because he required no creation interventions in nature, meaning he "insulated god from any requirement to intervene in nature, either as creator or as administrator." Therefore the most complete explanation in regard to the natural, as well as the artificial, is for the most part teleological. In fact, proposals that species had changed by chance survival of the fittest, similar to what is now called "natural selection," were already known to Aristotle, and he rejected these with the same logic. He conceded that monstrosities (new forms of life) could come about by chance, but he disagreed with those who ascribed all nature purely to chance because he believed science can only provide a general account of that which is normal, "always, or for the most part." The distinction between what is normal, or by nature, and what is "accidental," or not by nature, is important in Aristotle's understanding of nature. As pointed out by Sedley, "Aristotle is happy to say (Physics II 8, 199a33-b4) without the slightest fear of blasphemy, crafts make occasional mistakes; therefore, by analogy, so can nature."
The question of how to understand Aristotle's conception of nature having a purpose and direction something like human activity is controversial in the details. Martha Nussbaum for example has argued that in his biology this approach was practical and meant to show nature only being analogous to human art, explanations of an organ being greatly informed by knowledge of its essential function.
Galen's connection of the teleological argument to discussions about the complexity of living things, and his insistence that this is possible for a practical scientist, foreshadows some aspects of modern uses of the teleological argument.
Medieval philosophy and theology
Late classical Christian writers
As an appeal to general revelation, Paul the Apostle (AD 5–67) argues in Romans 1:18–20 that because it has been made plain to all from what has been created in the world, it is obvious that there is a God.
Marcus Minucius Felix (c. late 2nd to 3rd century), an Early Christian writer, argued for the existence of God based on the analogy of an ordered house in his The Orders of Minucius Felix: "Supposing you went into a house and found everything neat, orderly and well-kept, surely you would assume it had a master, and one much better than the good things, his belongings; so in this house of the universe, when throughout heaven and earth you see the marks of foresight, order and law, may you not assume that the lord and author of the universe is fairer than the stars themselves or than any portions of the entire world?"
Augustine of Hippo (AD 354–430) in The City of God mentioned the idea that the world's "well-ordered changes and movements", and "the fair appearance of all visible things" was evidence for the world being created, and "that it could not have been created save by God".
Islamic philosophy
Early Islamic philosophy played an important role in developing the philosophical understandings of God among Jewish and Christian thinkers in the Middle Ages, but concerning the teleological argument one of the lasting effects of this tradition came from its discussions of the difficulties which this type of proof has. Various forms of the argument from design have been used by Islamic theologians and philosophers from the time of the early Mutakallimun theologians in the 9th century, although it is rejected by fundamentalist or literalist schools, for whom the mention of God in the Qu'ran should be sufficient evidence. The argument from design was also seen as an unconvincing sophism by the early Islamic philosopher Al-Farabi, who instead took the "emanationist" approach of the Neoplatonists such as Plotinus, whereby nature is rationally ordered, but God is not like a craftsman who literally manages the world. Later, Avicenna was also convinced of this, and proposed instead a cosmological argument for the existence of God.
The argument was however later accepted by both the Aristotelian philosopher Averroes (Ibn Rushd) and his great anti-philosophy opponent Al-Ghazali. Averroes' term for the argument was Dalīl al-ˁināya, which can be translated as "argument from providence". Both of them however accepted the argument because they believed it is explicitly mentioned in the Quran. Despite this, like Aristotle, the Neoplatonists, and Al-Farabi, Averroes proposed that order and continual motion in the world is caused by God's intellect. Whether Averroes was an "emanationist" like his predecessors has been a subject of disagreement and uncertainty. But it is generally agreed that what he adapted from those traditions, agreed with them about the fact that God does not create in the same way as a craftsman.
In fact then, Averroes treated the teleological argument as one of two "religious" arguments for the existence of God. The principal demonstrative proof is, according to Averroes, Aristotle's proof from motion in the universe that there must be a first mover which causes everything else to move. Averroes' position that the most logically valid proof should be physical rather than metaphysical (because then metaphysics would be proving itself) was in conscious opposition to the position of Avicenna. Later Jewish and Christian philosophers such as Thomas Aquinas were aware of this debate, and generally took a position closer to Avicenna.
Jewish philosophy
An example of the teleological argument in Jewish philosophy appears when the medieval Aristotelian philosopher Maimonides cites the passage in Isaiah 40:26, where the "Holy One" says: "Lift up your eyes on high, and behold who hath created these things, that bringeth out their host by number:" However, Barry Holtz calls this "a crude form of the argument from design", and that this "is only one possible way of reading the text". He asserts that "Generally, in the biblical texts the existence of God is taken for granted."
Maimonides also recalled that Abraham (in the midrash, or explanatory text, of Genesis Rabbah 39:1) recognized the existence of "one transcendent deity from the fact that the world around him exhibits an order and design". Because of these examples, the 19th century philosopher Nachman Krochmal called the argument from design "a cardinal principle of the Jewish faith".
The American orthodox rabbi, Aryeh Kaplan, retells a legend about the 2nd century AD Rabbi Meir. When told by a philosopher that he did not believe that the world was created by God, the rabbi produced a beautiful poem that he claimed had come into being when a cat accidentally knocked over a pot of ink, "spilling ink all over the document. This poem was the result." The philosopher exclaims that would be impossible: "There must be an author. There must be a scribe." The rabbi concludes, "How could the universe ... come into being by itself? There must be an Author. There must be a Creator."
Thomas Aquinas
thumb|upright|The fifth of Thomas Aquinas' proofs of God's existence was based on teleology.
Thomas Aquinas (1225–1274), whose writings became widely accepted within Catholic western Europe, was heavily influenced by Aristotle, Averroes, and other Islamic and Jewish philosophers. He presented a teleological argument in his Summa Theologica. In the work, Aquinas presented five ways in which he attempted to prove the existence of God: the quinque viae. These arguments feature only a posteriori arguments, rather than literal reading of holy texts. He sums up his teleological argument as follows:
Aquinas notes that the existence of final causes, by which a cause is directed toward an effect, can only be explained by an appeal to intelligence. However, as natural bodies aside from humans do not possess intelligence, there must, he reasons, exist a being that directs final causes at every moment. That being is what we call God.
This view, that "God is known from his works", was supported and popularized by Newton's friends Richard Bentley, Samuel Clarke and William Whiston in the Boyle lectures, which Newton supervised. Newton wrote to Bentley, just before Bentley delivered the first lecture, that:
The German philosopher Gottfried Leibniz disagreed with Newton's view of design in the teleological argument. In the Leibniz–Clarke correspondence, Samuel Clarke argued Newton's case that God constantly intervenes in the world to keep His design adjusted, while Leibniz thought that the universe was created in such a way that God would not need to intervene at all. As quoted by Ayval Leshem, Leibniz wrote:
Leibniz considered the argument from design to have "only moral certainty" unless it was supported by his own idea of pre-established harmony expounded in his Monadology. Bertrand Russell wrote that "The proof from the pre-established harmony is a particular form of the so-called physico-theological proof, otherwise known as the argument from design." According to Leibniz, the universe is completely made from individual substances known as monads, programmed to act in a predetermined way. Russell wrote:
Natural-law argument
The natural-law argument for the existence of God states that the observation of governing laws and existing order in the universe indicates the existence of a superior being who enacted these laws. The argument was popularised by Isaac Newton, René Descartes, and Robert Boyle. The argument of natural laws as a basis for God was changed by Christian figures such as Thomas Aquinas, in order to fit biblical scripture and establish a Judeo-Christian teleological law.
Bertrand Russell criticized the argument, arguing that many of the things considered to be laws of nature, in fact, are human conventions. The teleological argument assumes that one can infer the existence of intelligent design merely by examination, and because life is reminiscent of something a human might design, it too must have been designed. However, considering "snowflakes and crystals of certain salts", "[i]n no case do we find intelligence". "There are other ways that order and design can come about" such as by "purely physical forces."
British empiricists
The 17th-century Dutch writers Lessius and Grotius argued that the intricate structure of the world, like that of a house, was unlikely to have arisen by chance. The empiricist John Locke, writing in the late 17th century, developed the Aristotelian idea that, excluding geometry, all science must attain its knowledge a posteriori—through sensual experience. In response to Locke, Anglican Irish Bishop George Berkeley advanced a form of idealism in which things only continue to exist when they are perceived. When humans do not perceive objects, they continue to exist because God is perceiving them. Therefore, in order for objects to remain in existence, God must exist omnipresently.
David Hume, in the mid-18th century, referred to the teleological argument in his A Treatise of Human Nature. Here, he appears to give his support to the argument from design. John Wright notes that "Indeed, he claims that the whole thrust of his analysis of causality in the Treatise supports the Design argument", and that, according to Hume, "we are obliged 'to infer an infinitely perfect Architect.
However, later he was more critical of the argument in his An Enquiry Concerning Human Understanding. This was presented as a dialogue between Hume and "a friend who loves sceptical paradoxes", where the friend gives a version of the argument by saying of its proponents, they "paint in the most magnificent colours the order, beauty, and wise arrangement of the universe; and then ask if such a glorious display of intelligence could come from a random coming together of atoms, or if chance could produce something that the greatest genius can never sufficiently admire".
Hume also presented arguments both for and against the teleological argument in his Dialogues Concerning Natural Religion. The character Cleanthes, summarizing the teleological argument, likens the universe to a man-made machine, and concludes by the principle of similar effects and similar causes that it must have a designing intelligence:
Robin Collins argues that the universe is fine-tuned for scientific discoverability, and that this fine-tuning cannot be explained by the multiverse hypothesis. According to Collins, the universe's laws, fundamental parameters, and initial conditions must be just right for the universe to be as discoverable as ours. According to Collins, examples of fine-tuning for discoverability include:
- The fine-structure constant is fine-tuned for energy usage. If it were stronger, there would be no practical way to harness energy. If it were weaker, fire would burn through wood too quickly and energy usage would be impractical.
- The baryon-to-photon ratio allowed for the discovery of the big bang via the cosmic microwave background.
- Many things in particle physics are within a narrow range required for discoverability, such as the mass of the Higgs boson.
Creation science and intelligent design
A version of the argument from design is central to both creation science and intelligent design,
The teaching of evolution was effectively barred from United States public school curricula by the outcome of the 1925 Scopes Trial, but in the 1960s the National Defense Education Act led to the Biological Sciences Curriculum Study reintroducing the teaching of evolution. In response, there was a resurgence of creationism, now presented as "creation science", based on biblical literalism but with Bible quotes optional. ("Explicit references to the Bible were optional: Morris's 1974 book Scientific Creationism came in two versions, one with Bible quotes, and one without.")
Scientists disagreed with the assertion that intelligent design is scientific, and its introduction into the science curriculum of a Pennsylvania school district led to the 2005 Kitzmiller v. Dover Area School District trial, which ruled that the "intelligent design" arguments are essentially religious in nature and not science.
Proponents of the intelligent design movement such as Cornelius G. Hunter, have asserted that the methodological naturalism upon which science is based is religious in nature. They commonly refer to it as 'scientific materialism' or as 'methodological materialism' and conflate it with 'metaphysical naturalism'. They use this assertion to support their claim that modern science is atheistic, and contrast it with their preferred approach of a revived natural philosophy which welcomes supernatural explanations for natural phenomena and supports theistic science. This ignores the distinction between science and religion, established in Ancient Greece, in which science can not use supernatural explanations.
Intelligent design advocate and biochemist Michael Behe proposed a development of Paley's watch analogy in which he argued in favour of intelligent design. Unlike Paley, Behe only attempts to prove the existence of an intelligent designer, rather than the God of classical theism. Behe uses the analogy of a mousetrap to propose irreducible complexity: he argues that if a mousetrap loses just one of its parts, it can no longer function as a mousetrap. He argues that irreducible complexity in an object guarantees the presence of intelligent design. Behe claims that there are instances of irreducible complexity in the natural world and that parts of the world must have been designed. This negative argument against step by step evolution ignores longstanding evidence that evolution proceeds through changes of function from preceding systems. The specific examples Behe proposes have been shown to have simpler homologues which could act as precursors with different functions. His arguments have been rebutted, both in general and in specific cases by numerous scientific papers. In response, Behe and others, "ironically, given the absence of any detail in their own explanation, complain that the proffered explanations lack sufficient detail to be empirically tested".
"Third way" proposal
University of Chicago geneticist James A. Shapiro, writing in the Boston Review, states that advancements in genetics and molecular biology, and "the growing realization that cells have molecular computing networks which process information about internal operations and about the external environment to make decisions controlling growth, movement, and differentiation", have implications for the teleological argument. Shapiro states that these "natural genetic engineering" systems, can produce radical reorganizations of the "genetic apparatus within a single cell generation". Shapiro suggests what he calls a 'Third Way'; a non-creationist, non-Darwinian type of evolution: