Editing Specified complexity (section)

==Definition==

===Orgel's terminology===
The term "specified complexity" was originally coined by [[origin of life]] researcher [[Leslie Orgel]] in his 1973 book ''The Origins of Life: Molecules and Natural Selection'',<ref name="NCSE Orgel">{{cite web | title=Review: Origins of Life | website=NCSE | url=http://ncse.com/rncse/27/3-4/review-origins-life | access-date=1 June 2016| date=2015-12-15 }}</ref> which proposed that [[RNA]] could have evolved through Darwinian [[natural selection]].<ref name="Salk Institute for Biological Studies 2007">{{cite web | title=Salk Chemical Evolution Scientist Leslie Orgel Dies | website=Salk Institute for Biological Studies | date=30 October 2007 | url=http://www.salk.edu/news-release/salk-chemical-evolution-scientist-leslie-orgel-dies/ | access-date=1 June 2016}}</ref> Orgel used the phrase in discussing the differences between life and non-living structures:

<blockquote>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 that 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.<ref>Leslie Orgel (1973). ''The Origins of Life'', p. 189.</ref></blockquote>

The phrase was taken up by the creationists [[Charles Thaxton]] and [[Walter Bradley (engineer)|Walter L Bradley]] in a chapter they contributed to the 1994 book ''The Creation Hypothesis'' where they discussed "design detection" and redefined "specified complexity" as a way of measuring information. Another contribution to the book was written by [[William A. Dembski]], who took this up as the basis of his subsequent work.<ref name="NCSE Orgel" />

The term was later employed by physicist [[Paul Davies]] to qualify the complexity of living organisms:

<blockquote>Living organisms are mysterious not for their complexity per se, but for their tightly specified complexity<ref>Paul Davies (1999). ''The Fifth Miracle'' p. 112.</ref></blockquote>

===Dembski's definition===
Whereas Orgel used the term for biological features which are considered in science to have arisen through a process of evolution, Dembski says that it describes features which cannot form through "undirected" evolution&mdash;and concludes that it allows one to infer intelligent design. While Orgel employed the concept in a qualitative way, Dembski's use is intended to be quantitative. Dembski's use of the concept dates to his 1998 monograph ''[[The Design Inference]]''. Specified complexity is fundamental to his approach to intelligent design, and each of his subsequent books has also dealt significantly with the concept. He has stated that, in his opinion, "if there is a way to detect design, specified complexity is it".<ref>William A. Dembski (2002). ''[[No Free Lunch (book)|No Free Lunch]]'', p. 19.</ref>

Dembski asserts that specified complexity is present in a configuration when it can be described by a pattern that displays a large amount of independently specified information and is also complex, which he defines as having a low probability of occurrence. He provides the following examples to demonstrate the concept: "A single letter of the alphabet is specified without being complex. A long sentence of random letters is complex without being specified. A Shakespearean sonnet is both complex and specified."<ref>William A. Dembski (1999). ''Intelligent Design'', p. 47.</ref>

In his earlier papers Dembski defined ''complex specified information'' (CSI) as being present in a specified event whose probability did not exceed 1 in 10<sup>150</sup>, which he calls the [[universal probability bound]]. In that context, "specified" meant what in later work he called "pre-specified", that is specified by the unnamed designer before any information about the outcome is known. The value of the universal probability bound corresponds to the inverse of the upper limit of "the total number of [possible] specified events throughout cosmic history", as calculated by Dembski.<ref>William A. Dembski (2004). ''[[The Design Revolution |The Design Revolution: Answering the Toughest Questions About Intelligent Design]]'', p. 85.</ref>
Anything below this bound has CSI. The terms "specified complexity" and "complex specified information" are used interchangeably. In more recent papers Dembski has redefined the universal probability bound, with reference to another number, corresponding to the total number of bit operations that could possibly have been performed in the entire history of the universe.

Dembski asserts that CSI exists in numerous features of living things, such as in [[DNA]] and in other functional biological molecules, and argues that it cannot be generated by the only known natural mechanisms of [[physical law]] and chance, or by their combination. He argues that this is so because laws can only shift around or lose information, but do not produce it, and because chance can produce complex unspecified information, or simple specified information, but not CSI; he provides a mathematical analysis that he claims demonstrates that law and chance working together cannot generate CSI, either. Moreover, he claims that CSI is [[holism|holistic]], with the whole being greater than the sum of the parts, and that this decisively eliminates Darwinian evolution as a possible means of its "creation". Dembski maintains that by process of elimination, CSI is best explained as being due to intelligence, and is therefore a reliable indicator of design.