Skip navigation.

Introduction to the Site

(Last updated April 30, 2003)

Q. What is the purpose of

A. was created to provide a one-stop location for responses to the arguments of the Intelligent Design (ID) movement. Many articles critical of ID are scattered around the Web. provides links to the best and most up-to-date of these articles, as well as a collection of articles written specifically for this site. It also provides other material relevant to ID, including links to the web sites of ID advocates.


Q. Who runs

A. is run by several volunteers, of a variety of religious and philosophical persuasions, who are all critics of ID and supporters of mainstream evolutionary biology. is hosted by the TalkOrigins Archive, a longstanding web site devoted to the the wider creation/evolution controversy. The TalkOrigins Archive Foundation, a Texas 501(c)(3) tax-exempt non-profit organization, provides the support for the TalkOrigins Archive, TalkDesign, the Panda's Thumb, and


Q. What is Intelligent Design?

A. The beliefs of ID advocates vary greatly. But the core beliefs which they all appear to share are the following:

(a) The action of an intelligent (presumably conscious) being was involved in the evolution of living organisms.

(b) There already exists empirical evidence of this action, sufficient to justify a scientific inference that such action occurred.

The term "Intelligent Design" usually refers to these beliefs together with the arguments which are made in support of them.

It is important to note that people who hold belief (a) but not belief (b) do not generally consider themselves to be advocates of ID, and this web site has no quarrel with such people. It is the claim that there is empirical evidence of design in biology which has provoked a controversy, and which we consider to be false. We argue that this claim is based on pseudoscience, and enjoys the support it does only because it appeals to the religious and/or ideological beliefs of its adherents.


Q. What is the Intelligent Design movement?

A. The ID movement has grown out of a creationist tradition which argues against evolutionary theory from a religious (usually Christian) standpoint. Although ID advocates often claim that they are only arguing for the existence of a "designer", who may or may not be God, all the leading advocates do believe that the designer is God, and frequently accompany their allegedly scientific arguments with discussion of religious issues, especially when addressing religious audiences. In front of other audiences, they downplay the religious aspects of their agenda.

Lawyer and creationist Phillip Johnson is usually credited with having founded the Intelligent Design movement, with the avowed intention of overthrowing "materialist science", and replacing it with "theistic science". This agenda is now being actively pursued by a well-funded body, the Center for Science and Culture (CSC), part of the Discovery Institute, a right-wing think tank funded by conservative Christians. (Until recently, the CSC was known as the Center for the Renewal of Science and Culture; the name change is most likely an attempt to render their ideological adgenda less overt.) The CSC now plays the leading role in the promotion of ID, and its fellows include most of the leading ID advocates: William Dembski, Michael Behe, Jonathan Wells, Stephen Meyer, etc. The goal of their Wedge Strategy is for ID to become "the dominant perspective in science" and to "permeate our religious, cultural, moral and political life".

Realizing that their "scientific" arguments have little chance of acceptance within the mainstream scientific community, ID advocates address their arguments primarily to the general public, politicians, philosophers, and other non-scientists. The allegedly scientific material which they produce is full of misleading rhetoric, equivocal terminology, and misrepresentations of the facts. They also produce much material which does not even aspire to be scientific, and which can frankly be best described as propaganda.


 Q. Do scientists support Intelligent Design?

A. ID advocates are very keen to give the impression that they have the support of scientists. It is true that a number of scientists support ID, as indeed there are scientists who support Young Earth Creationism and many other pseudosciences. But they are a tiny number in relation to the total number of scientists, the vast majority of whom support evolutionary theory.

In 2001, the Discovery Institute took out advertisements in national newspapers to announce that 100 scientists had signed a statement saying that they were "skeptical of claims for the ability of random mutation and natural selection to account for the complexity of life." The signatories did not say that they supported ID, though some of them certainly do. Compare this with a letter sent to Congress in support of the current teaching of evolution in schools, signed by the presidents of 80 scientific organizations. To put things into perspective, the National Center for Science Education (NCSE), a group which supports the teaching of evolution in public schools, released Project Steve, a spoof on anti-evolutionist lists such as the one by the Discovery Institute mentioned above. Signatories to the list agreed to a statement supporting evolution and rejecting ID, but there’s one catch: all of the signatories are named "Steve" or a version thereof. Given that Steves make up approximately 1% of the population, the 300+ signatories (at the time of this writing) indicate that for every scientist agreeing with the Discovery Institute, perhaps as many as a few hundred disagree.


 Q. Is opposition to Intelligent Design based on naturalism?

A. Intelligent Design is rejected by the vast majority of scientists, particularly those in the relevant fields. The proportion of scientists who accept ID is insignificant. To explain away this overwhelming rejection of their arguments by those who are experts in the subject, ID advocates employ an ad hominem argument. They accuse the vast mass of scientists of being too biased by a commitment to "materialism" or "naturalism" to be able to judge the arguments fairly. This is despite the fact that many of these scientists are themselves theists.

It is true that many (though not all) mainstream scientists and philosophers of science argue that science must be committed to a principle of "methodological naturalism", which states that only "natural" explanations can be allowed in science. Unfortunately, the meaning of the term "natural" is unclear. It is often assumed that this would rule out any explanations involving divine action, but it may be that a hypothesis involving divine action could be considered "natural" if it was empirically testable. These are murky philosophical waters, and it seems that most scientists simply adopt the principle of methodological naturalism as rule of thumb, based on the more general principle that extraordinary claims require extraordinary evidence. More importantly, good scientific theories contain virtues like testability, parsimony, and explanatory power. ID tends to be lacking these virtues and many others; the "naturalism" claim is often a cover for the fact that ID has a difficult time meeting basic scientific criteria.

In any case, ID advocates assure us that their arguments do not imply a divine designer. The designer could have been an extraterrestrial alien. Methodological naturalism certainly does not rule out such a designer. Confusion over this issue has been caused by the ambiguity of the word "natural", which can mean either "not artificial" or "not supernatural" (in addition to other possible meanings). ID advocates frequently conflate these definitions for rhetorical purposes. This issue is explored in greater detail in Mark Issak’s essay, A Philosophical Premise of ‘Naturalism’?


Q. Is Intelligent Design a form of creationism?

A. The answer to this question depends partly on what one means by "creationism". At one end of the spectrum, creationism can be simply the belief that the Universe was created by God, a belief which is probably shared by all monotheists. At the other end, it can be Young Earth Creationism, the belief that the Genesis account of creation is literally true and that the scientific evidence supports this belief. A reasonable intermediate definition is the belief that individual species or "kinds" of animals were divinely created.

The core ID belief does not strictly entail divine involvement in the origin of species, but all the leading ID advocates believe in such involvement. Many (perhaps most) also deny common descent, the continuity of descent from parent to offspring from the earliest organisms down to the present day. Much of the CSC's material attacks common descent. Deniers of common descent include Phillip Johnson and Jonathan Wells. Dembski is ambivalent on the subject, attempting to cast doubt on common descent without actually denying it. At least one fellow of the CSC, Paul Nelson, is a Young Earth Creationist.

Part of the strategy of ID is to create a "big tent", in which all opponents of evolutionary theory can join forces, from the most extreme Young Earth Creationists to those, such as Michael Behe, who accept virtually all of evolutionary theory except the proposition that evolution was fully natural. In order to maintain the unity of this big tent, those towards the latter end of the spectrum are careful to avoid criticizing even the most egregious arguments of the Young Earth Creationists.

Furthermore, many of the ID arguments and tactics are very similar to those of Young Earth or Old Earth Creationists. Irrelevant appeals to information theory and thermodynamics; bogus probability calculations based on purely random combinations of proteins; gaps in the fossil record; use of out-of-context quotations; all of these and others are staples of the creationist menu.

A major distinguishing feature of ID is the attempt to shift the focus of the debate away from the details of Earth history and towards more abstract concepts such as "design" or "teleology", terms which are rarely used in a non-question-begging manner. Unlike Young Earth Creationism, which is very easy to falsify, ID is difficult or impossible to test according to standard scientific practice. This gives the ID movement a tactical advantage by allowing its adherents to argue from a position that holds no testable affirmative beliefs, yet allows them to attack almost any aspect of evolutionary theory they think might be vulnerable. Note that this does not make ID a better theory than creationism; many argue that this renders ID even less scientific.

It is also clear that much of the motivation for creating an ID movement distinct (to some degree) from the existing creationist movement was to evade the legal restriction (in the U.S.A.) on teaching creationism in public schools. The U.S. Supreme Court has ruled that "scientific" creationism is a religious position, and therefore violates the First Amendment's constitutional separation of Church and State. One of the more telling commonalities between the creationist and ID movements is the primary focus on getting their views taught in public schools despite the lack of endorsement from the scientific community.

Whether these many connections between ID and creationism justify considering ID to be a form of creationism is ultimately a matter of individual judgment. Many have concluded that they do, and one will sometimes see ID referred to as IDC, or Intelligent Design Creationism. While sometimes frank about the religious and political aspirations of ID, advocates at other times will try to create the impression that ID is a purely scientific issue. Use of the term Intelligent Design Creationism helps to draw attention to the true nature of the movement.


Q. Is Intelligent Design a pseudoscience?

A. We argue that Intelligent Design is a pseudoscience, like Young Earth Creationism, astrology, Atlantis, and the many other belief systems parading as science which fill the mass media. By pseudoscience, we mean a belief system which is claimed to be based on science, but which is actually based on arguments that are not only flawed, but are so egregiously bad that they do not stand up to any serious open-minded examination. Advocates of pseudoscience are motivated by a dogmatic commitment to their position which renders their minds closed to contrary arguments. Common (though not universal) additional symptoms of pseudoscience include the following: arguments are directed towards an audience of non-scientists; grandiose claims are made, often in fields where the claimant has little expertise (viz Dembski's claims to new laws of information and thermodynamics); the overwhelming mass of scientists are claimed to be too biased to judge the arguments fairly; arguments are couched in superfluous technical jargon; arguments use poorly defined new technical terms (or old terms given new meanings); technical arguments are outnumbered by rhetoric; excessive use is made of quotations, often from popular books and often out of context.


 Q. What are the "scientific" arguments used to support Intelligent Design?

A. The arguments for Intelligent Design are primarily arguments from ignorance, also known as god-of-the-gaps arguments. ID advocates also claim to have positive evidence of ID, in the form of "specified complexity" and "irreducible complexity", but these arguments turn out to be disguised arguments from ignorance. In addition, ID advocates sometimes make an argument from analogy. A lot of their effort is also devoted to attacking specific aspects of evolutionary theory, rather than giving support to their own ID hypothesis.


Q. What is the argument from ignorance, or god-of-the-gaps argument?

A. ID advocates point out that the evolution of certain biological structures has not been fully explained by biologists. This is true, and will continue to be true for the foreseeable future, since our knowledge of such structures is highly limited at present. From this, they conclude that those biological structures cannot have an evolutionary explanation, and so must have been designed by an intelligent agent. Although this line of argument can sometimes be seen clearly in their work, more often they disguise the argument with a lot of superfluous and misleading terminology, such as "irreducible complexity", "specified complexity" and "information".


Q. What is the argument from analogy?

A. The argument from analogy typically runs as follows. Biological systems have some quality in common with man-made machines, e.g. they consist of multiple coordinated parts. Whenever we have directly observed the origin of such a machine, an intelligent being was responsible for designing it. Therefore an intelligent being must have designed biological systems. Here is an example of such an argument:

"In order to reach a conclusion based on an analogy, it is only necessary that the induction flow out of the shared properties: The irreducibly complex Rube Goldberg machine required an intelligent designer to produce it; therefore the irreducibly complex blood-clotting system required a designer also." (Michael Behe, "Darwin's Black Box", p. 218)

Arguments from analogy, a type of inductive argument, are notoriously unreliable. The onus is on the advocate of the argument to make a compelling case for the significance of the shared properties and the insignificance of the divergent properties (or disanalogies). In fact, biological systems are very different from man-made machines in all sorts of ways. The most fundamental difference is that biological organisms, unlike man-made machines, have reproduced themselves over millions of generations with random variation and natural selection. This process is known to result in adaptation, and some degree of adaptation by natural evolution is accepted even by ID advocates. To make an argument from analogy in the face of such a fundamental disanalogy is unreasonable.

If we ignore significant disanalogies, as ID advocates do, then it is easy to arrive at absurd conclusions. For example, since it was humans who were responsible for designing the machines of which we have directly observed the origin, should we not infer that biological "machines" were designed by humans? Before the first balloon flight of the Montgolfier brothers, we might have inferred that, because all wingless creatures were then unable to fly, human beings would not be able to fly. (At some time in the past scientists might have had good reasons to think that human flight would be impossible, but those reasons would have been based on their current knowledge of physics, not on an absurd argument from analogy.)


Q. What is "irreducible complexity"?

A. The term "irreducibility complexity" was introduced by biochemist Michael Behe. ID advocates claim that an irreducibly complex biochemical system cannot (with any reasonable degree of probability) have evolved by natural evolution. Irreducible complexity was originally defined in such a way that it could be detected simply by observing the current state of a system, without any consideration of how it might have evolved (rather like the second sense of specified complexity above): if the removal of any part of a biochemical system would render that system non-functional, then it was considered to be irreducibly complex. Acknowledged problems with this definition have forced Behe and Dembski to propose new definitions, which increasingly require the observer to consider the possibility of evolutionary predecessors in determining whether a system is irreducibly complex. This makes it increasingly difficult to judge whether a system is irreducibly complex or not.

However, even if a system is judged irreducibly complex by any of the available definitions, this does not rule out the possibility of an evolutionary origin. The arguments of Behe and Dembski are based on the assumption that a system retains the same function as it evolves. But biological systems often become adapted to new functions as they evolve. Behe divided possible evolutionary pathways into two categories: "direct" pathways, which do not involve a change of function, and "indirect" pathways" which do. He then gave an argument against the viability of "direct" evolutionary pathways to an irreducibly complex system. He also claimed that the probability of evolution by an indirect pathway was too low for this to be an acceptable explanation. However, this claim was based on nothing more than his own intuition and an argument from ignorance: biologists have not yet provided a detailed account of any such pathway.

In fact, biologists have now proposed evolutionary explanations for several of the systems introduced as examples by Behe, such as the immune system, but these will probably not be detailed enough to satisfy Behe or Dembski, who demand a precise account of every step of the pathway. Nevertheless, as these explanations gradually become more detailed, ID advocates increasingly choose to concentrate on just one of Behe's examples, the bacterial flagellum, which is perhaps the least well explained at present.

Detailed critiques of Behe's arguments can be found here. See also Irreducible Complexity Demystified.


Q. What is "specified complexity"?

A. ID advocates claim that "specified complexity" is a reliable marker of intelligent design. However, they use the term in two quite different senses, which they tend to conflate.

The term "specified complexity" was coined by biologist Leslie Orgel, as a way of characterizing what it is that distinguishes living organisms from non-living objects. The term was later adopted and used in a similar way by physicist Paul Davies. For these writers, an object is complex if it cannot be compressed to a shorter description. For example, a sequence of 100 identical digits, "1111111111...", can be compressed to the description "100 1s", and is therefore not complex at all. On the other hand, a sequence of 100 random binary digits is complex because it cannot be compressed in this way. This corresponds to a widely-used concept in information theory, known as "algorithmic information" or "Kolmogorov complexity". Since random sequences are highly complex in this sense, it is clear that complexity alone is not enough to characterize life. So Orgel and Davies add the criterion of "specification" or "specificity". Specificity can broadly be thought of here as indicating the presence of some special property. Davies gives the example of a DNA sequence, which is "specified" because it is a member of that special set of sequences which code for a living organism. Orgel summarizes as follows:

In brief, living organisms are distinguished by their specified complexity. Crystals are usually taken as the prototypes of simple well-specified structures, because they consist of a very large number of identical molecules packed together in a uniform way. Lumps of granite or random mixtures of polymers are examples of structures which are complex but not specified. The crystals fail to qualify as living because they lack complexity; the mixtures of polymers fail to qualify because they lack specificity. [Leslie Orgel, "The Origins of Life", Chapman & Hall, 1973.]

The term "specified complexity" has now been recycled by Intelligent Design advocate William Dembski, a mathematician and philosopher. He, however, uses the word "complexity" in a very different sense. For Dembski, "complexity" is merely a rescaled measure of improbability. If an object has only a small probability of occurring, he labels it "complex", regardless of whether it is simple or complex in the usual sense of the words. If the origin of an object can be shown to have sufficiently small probability under a particular hypothesis, Dembski tells us to reject that hypothesis as an explanation for the origin of the object. (In calculating the probability, we must consider not only the particular form of the object that we observed, but any other forms which would match the same "specification", e.g. other objects which perform the same function; hence the word "specified".) If all the natural (non-design) hypotheses we can think of to explain the object can be rejected, and we have "compelling reasons to think" that there can be no other natural explanation, then Dembski tells us the object exhibits specified complexity and we should infer that it was designed.

For example, Dembski describes a case in which a Democrat politician, Nicholas Caputo, was responsible for drawing the ballot order in elections. In 40 out of 41 elections, Caputo gave a Democrat candidate first position on the ballot, a position which was known to be advantageous. Dembski represents this event by the following sequence of 40 Ds and one R:


Caputo claimed that he had determined the ballot order by drawing capsules from an urn, giving Democrats and Republicans an equal chance of heading the ballot. Under the hypothesis that this was true, Dembski calculates the probability of drawing 40 or more Ds as about 1 in 50 billion ("40 or more Ds" is the specification), and decides that this probability is sufficiently low to justify rejecting this hypothesis. He also claims that we have a compelling reason to think there could be no other natural explanation, on the grounds that "urn models are among the most reliable randomization techniques available". He therefore concludes the sequence above exhibits specified complexity, and was the result of design. So, in Dembski's sense, even a very simple phenomenon like this sequence can exhibit specified complexity. (Clearly, if Caputo had put the Democrats first all 41 times, there would have been even more reason to infer design, following Dembski's approach, and the sequence of all 41 Ds would also have exhibited specified complexity.)

Unfortunately, Dembski conflates his own usage of the term "specified complexity" with that of Orgel and Davies, although they are quite different. Most biologists would agree that living organisms exhibit specified complexity in the sense of Orgel and Davies. They would not agree that living organisms exhibit specified complexity in Dembski's sense, since they would not accept that he has given compelling reasons to think that any biological structure could not have evolved naturally.

It should be added that the above is an interpretation of what Dembski means by specified complexity. But he is extremely vague and equivocal on the subject, refusing to be pinned down to any precise definition. It therefore impossible for anyone to say with certainty what he means.


Q. How has Dembski applied his "specified complexity" method to infer design in biology?

A. Dembski has provided only one detailed application of his method to biology, namely to the flagellum of the bacterium E. coli. This occurs in his latest book No Free Lunch. In this case, the natural hypothesis which Dembski considers is the hypothesis that the flagellum appeared as a result of a purely random combination of proteins. It does not take into account any non-random effects. Most significantly, it ignores natural selection, the central principle of evolution theory. The hypothesis of purely random combination is already universally rejected by biologists (it is the old creationist "tornado in a junkyard" straw man), so Dembski's consideration of this hypothesis serves no useful function, and the probability calculation which he uses to reject the hypothesis is irrelevant.

Since Dembski's probability calculation is irrelevant, all that really matters are his "compelling reasons to think" that there can be no other natural explanation (he calls this a "proscriptive generalization"). This takes the form of an argument from irreducible complexity, so we see that, when all the misleading terminology about "specified complexity" is unraveled, Dembski is just making another argument from irreducible complexity. What has he added to Behe's argument? Very little. Although he has tightened up Behe's argument against "direct" paths of evolution, he again fails to consider the possibility of the flagellum evolving from a system with a different function. Changes of function are commonplace in evolution, and are often referred to as "co-option" or "co-optation". Dembski mentions co-option, but only considers the possibility of individual proteins being co-opted. He ignores the scenario which biologists actual propose, which is the co-option of a substantial part of the system, consisting of many proteins, as a unit.

Biologists propose that the flagellum evolved from a secretory system. Indeed, the modern flagellum still retains the function of a secretory system. Although this scenario has not been developed to the level of detail which Behe and Dembski demand, it is highly misleading for Dembski to claim, as he does, that biologists "don't have a clue" how the flagellum evolved.

Detailed critiques of Dembski's arguments can be found here.


Q. How does "information" enter the picture?

A. Intelligent Design advocates frequently make vague appeals to "information" in support of their arguments, claiming that the information in living organisms cannot be generated except by intelligent design. These appeals are useless without a clear definition of what the term means.

A number of different definitions of information are used in the field of information theory, the two most common being algorithmic information and Shannon information. The former is also known as Kolmogorov complexity, and has been briefly described above. The latter is a probabilistic concept used primarily in communications, where the aim is to maximize the efficiency and reliability of message transmission; the meaning of the messages is immaterial. Both these types of information can be shown to be generated by natural processes.

Dembski has attempted to formalize the argument from information, but his formulation turns out to be just the same as his argument from complexity. He uses the terms "information" and "complexity" synonymously. Both are just rescaled measures of improbability. When Dembski says that an event exhibits high information, he means that it has low probability. His "complex specified information" is exactly the same as his "specified complexity", and he uses the two terms interchangeably. See Information Theory and Creationism for more.