Irreducible complexity

Irreducible complexity is a concept popularized by noted pseudoscientist Michael Behe in his 1996 book Darwin's Black Box to support intelligent design. Intelligent design pushers argue that while some systems and organs can be explained by evolution, those that are irreducibly complex cannot, and therefore an intelligent designer must be responsible.http://creationwiki.org/Irreducible_complexity 
Irreducible complexity stems from the claim that some biological systems appear to be too complex to have arisen by natural selection. Specifically, it argues that if you take a part away from an organism and it stops functioning (analogous to taking the engine out of a car), then it must be irreducibly complex and cannot have evolved. It is one of the main arguments of the Intelligent Design movement.
The concept is considered to be mostly bollocks when applied to evolution, because it fails to take into account numerous other pathways that a particular ability can evolve through — it assumes that evolution must go through "additive" processes to achieve its conclusion, and this isn't the case. Most evolutionary biologists do not consider it science by any stretch of the imagination because the idea relies on personal incredulity and unwarranted assumptions.
==Explanations==
==="Official" definition===
There is a slightly different definition of "irreducible complexity" related to emergent phenomena in systems theory and computational complexity theory. However, a full explanation of this is beyond the scope of this article.See Wikipedia: 
It is believed that Michael Behe has basically taken some of the ideas found within this theory and rehashed it slightly to apply to evolution. Behe's definitionMicheal Behe — Darwin's Black Box: The Biochemical Challenge to Evolution is that an irreducibly complex form is:
While surrounded by some fancy words and the language of science, this is just incredulity that the world could arise through (largely undirected) naturalistic processes. The argument is no more advanced or "evolved" than William Paley's "Watch Argument" which stated that as a watch looked created, it must have a creator. Essentially, Behe is stating "because I can't see a natural explanation, Goddidit" — this ignores any possibility that a naturalistic explanation or evolutionary pathway will later be discovered.
It's also quite telling that Behe never goes on to attempt to define "several" as a meaningful number, giving intelligent design a crucial untestability. It gives the creators infinite room to declare any number of things (that do not presently have an evolutionary explanation) "irreducibly complex", while at the same time denying the applicability to other structures with a known evolutionary history.
===Probability Analysis===
In calculating the probability for a mutation, one must consider not merely the probability that the mutation will arise, but the number of opportunities for that mutation. So if a mutation has only a one-in-a-million chance of happening, it's still very likely that the mutation will eventually occur if the species has millions of members. So now the question arises: if there are several different mutations under consideration, do we multiply all the probabilities together, and then compare the probability to the number of opportunities, or do we compare each probability to the number of opportunities, and then multiply the adjusted probabilities together? Evolutionary theory (and mathematical probability theory) tell us that we should do the latter; each mutation can arise independently, spread through the population by natural selection, and combine through sexual reproduction (or gene transfer in simpler organisms). Proponents of irreducible complexity assert that in most cases, the individual mutations do not provide any advantage by themselves, and so are not operated on by natural selection, and we must multiply the probability of all of the mutations first before considering the number of opportunities.
==Examples of flawed arguments==
Frequently, believers in irreducible complexity cite the eye as an example of something too complex to have evolved. They frequently introduce the argument with a question of the type, "What use is half an eye?". However, if the question is recast as "Given a choice, would you prefer to be completely blind or have 50% of your present vision?", then it becomes clear that the question is badly formed, especially when keeping in mind that many species manage to survive with significantly less-advanced eyes. Examples include the polychaete worms, which can distinguish between light and dark;Buchsbaum, R. Animals Without Backbones (Penguin 1958); vol.1, plate 64 the simple eye-cup of the flatworms, for finding the direction of a light source; jellyfish and scallops, with simple eyes for detecting movement;Scallop eyes the famous compound eyes of the insects, which can make out simple shapes; and ultimately the sophisticated single-lens eyes of the molluscs and vertebrates.
Another famed and also flawed example references "the watch on the beach". It goes as follows: "If you find a watch on the beach, do you assume it got there by chance, or do you assume it was made by an intelligent designer?" The example is flawed because watches and their parts do not reproduce or mutate. (And if they did, they could be produced by random mutation.Evolution IS a Blind Watchmaker: Video of a clock-'evolving' simulation) Moreover, nobody would assume that the watch had simply been summoned into existence by some mystery force; they would not only assume a watchmaker, but a whole history of work in associated technologies by hundreds if not thousands of individuals. Oddly, no ID advocate has ever argued that the "designer" is a giant committee of unrelated inventors.Then again, even polytheistic religions often attribute the creation of the universe to either a single creator deity or some primal force that existed before the gods themselves did.
The above arguments appeal to the common sense of the "Average Joe". However, given the numerous known flaws in human thought processes that even trained thinkers often struggle to overcome, popular support is quite understandably not part of the scientific method; bear in mind that a significant part of the world's population believes in astrology.
Although proponents offer irreducible complexity as evidence of intelligent design, this conclusion is questionable. Which parachute would you consider better designed — one which ceased to function if a single part was missing, or one which has a back-up pullcord? Irreducible complexity, if accepted as evidence of design, suggests at best crappy design.
Behe also has defined and redefined irreducible complexity:
In a famous early instance of an argument from "irreducible complexity" (although not by that name), Herbert Spencer (1820-1903) argued that the huge antlers of the together with the other bodily structures needed to support them formed a combination that could not have arisen by natural selection alone. "(I note in passing that Spencer's is exactly the argument that contemporary advocates of Intelligent have used to rejuvenate sclerotic Scientific Creationism; they seem to hope this infusion of monkey glands will unleash a new powerful refutation of Darwinian evolutionary theory.)"Robert J. Richards, Was Hitler a Darwinian?: Disputed Questions in the History of Evolutionary Theory. Chicago: University of Chicago Press, 2013, page 125 Spencer was not a creationist. Even though he advanced this argument against Darwin's mechanism of evolution, Spencer thought that he had a better mechanism (something like Lamarckism). He didn't see the elk as evidence for divine intervention. (Needless to say, today's advocates of "irreducible complexity" do not address Spencer's position.)
Another obvious counterpoint is that irreducible complexity can easily be demonstrated in technology, and the ID argument becomes utterly ludicrous when applied to the real process of design: for example, a modern steel-mill makes steel, but has vital components that are themselves made of steel. The ID claim, applied to this example, would go: "a designer must have magically created the steel components of the first mill", rather than imagining that perhaps the first steel was not made in a modern steel mill. (One might note that even children realize that simply invoking Santa Claus is not enough to account for the appearance of Christmas presents. There must be a crew of manufacturing elves and a reindeer-driven sleigh delivery-system, not to mention the North Pole as a manufacturing site.)
===So who designed God?===
Arguments from irreducible complexity must also take into account the question of whether or not God himself is a being of irreducible complexity:
*Answering "Yes" sends you flying into an infinite regress of who-designed-God's-designer, who-designed-the-designer's-designer... (and so on, ad inifinitum). Keep in mind that suddenly insisting that "God designed himself!" would mean you allow for self-design — making the very existence of any designer superfluous to begin with. And answering that God has "no beginning and no end" is just, for lack of a better way to articulate the problem, brain-breakingly dumb.
*Answering "No" means that life and the Universe couldn't have been intelligently designed either — because if even almighty God (read: the most "specified and complex" and thus most intelligently designed entity ever) fails to meet the criteria of the design inference, then nothing else will.
==How "Irreducibly complex" structures can evolve==
* One way in which "Irreducibly complex" structures could develop is via a process known as scaffolding, wherein a structure gains in complexity via duplication and mutation of parts, then parts are knocked out via mutations, leaving a structure with no direct linear development from the original, basic structure.
* Other paths by which irreducibly complex structures may form include cooption of parts from other structures. Both scaffolding and cooption can be seen in the case of the bacterial flagellum, which includes many parts taken from a secretory pump.
* Another potential path involves "function shift" or exaptation, which can also explain how irreducibly complex structures may evolve. During evolution, a feature may shift from one function to another — a classic example is the feathers of a bird. They originally evolved in dinosaurs as a way to keep warm, but birds then evolved and used some of the feathers for flight. Half a wing might not be useful for flying, but it will still keep you warm. Human arms provide another example — they were originally legs, but evolved into arms when we became bipedal.
Additionally, to assert that something is irreducibly complex is to assert that none of the parts could have provided a benefit by themselves. The more parts there are, the more impressive it is that all of them developed; however, this also means that there are more possibilities that have to be eliminated. For instance, if someone claims that there are ten parts to a particular irreducibly-complex structure, then there are ten different possibilities for which one developed first. If even just one of them has a use that we are unaware of, then the structure is not irreducibly complex.
==See also==
* Emergence
* The incontrovertible evidence of common descent
* Conservapedia:Probability
* Organized complexity
==External links==
* Response and explanation of the subject on EvoWiki
* Irreducible complexity and the scientific literature
* Kjeragbolten
* Rainbow Arch
==References==
==Notes==
Category:Pseudoscience
Category:Creationist claims
Category:Intelligent design creationism
ru:Некоторые системы владеют неуменьшаемой сложностью