Irreducible complexity

(Difference between revisions)
Jump to: navigation, search
(Scaffolding)
Line 10: Line 10:
 
The argument that evolution always proceeds by adding parts is false. Natural selection can remove parts as well as add them. For instance, whales have no hind legs, but retain vestigial pelvises where their ancestors' legs were attached.
 
The argument that evolution always proceeds by adding parts is false. Natural selection can remove parts as well as add them. For instance, whales have no hind legs, but retain vestigial pelvises where their ancestors' legs were attached.
  
Another example of an irreducibly complex system is a gothic arch: if any stone is removed, the arch falls down. The way to build such a system is to install a scaffold, build the arch, then remove the scaffolding. Similarly, biological mechanisms do not have to co-exist with the structures that allowed them to evolve the way they did.
+
Another example of an irreducibly complex system is a gothic arch: if any stone is removed, the arch falls down. The way to build such a system is to install a scaffold, build the arch, then remove the scaffolding. Similarly, biological mechanisms do not have to co-exist with the structures that allowed them to evolve the way they did. There is therefore no reason to accept the claim that if a system is irreducibly complex that it cannot be built gradually.
  
 
===Incomplete systems can still have a function===
 
===Incomplete systems can still have a function===

Revision as of 13:01, 13 June 2010

Wikipedia-logo-en.png
For more information, see the Wikipedia article:

Irreducible complexity, as defined by Michael Behe in Darwin's Black Box is a property of a system such that if any part is removed, the system ceases to function. Irreducible complexity is often used as an argument for Intelligent design.

The classic illustration of an irreducibly complex system is a mousetrap: it consists of a base, hammer, spring, catch (or trigger), and fasteners to hold the pieces together. If any of those parts is removed, the mousetrap no longer works.

The argument, then, is that since evolution proceeds by adding parts to an existing system one by one, the precursors of an irreducibly complex system would have been useless, and would not have been selected for. Ergo, all of the pieces had to be put together by an intelligent designer.

Contents

Counter-arguments

Scaffolding

The argument that evolution always proceeds by adding parts is false. Natural selection can remove parts as well as add them. For instance, whales have no hind legs, but retain vestigial pelvises where their ancestors' legs were attached.

Another example of an irreducibly complex system is a gothic arch: if any stone is removed, the arch falls down. The way to build such a system is to install a scaffold, build the arch, then remove the scaffolding. Similarly, biological mechanisms do not have to co-exist with the structures that allowed them to evolve the way they did. There is therefore no reason to accept the claim that if a system is irreducibly complex that it cannot be built gradually.

Incomplete systems can still have a function

While it is true that an irreducibly complex system with a missing part loses its original function, it may still have some other function. For instance, a mousetrap without a catch can still work as a tie clip, or a paperweight. A mousetrap without a base can be nailed to the floor. Such a mousetrap would not be as useful, but would still function.

For a biological example, consider the bacterial flagellum, a long spinning hair that functions as an "outboard motor" for bacteria. It is often cited as an example of an irreducibly complex system. But if some of its parts are removed, the resulting system bears a striking similarity to the Type Three Secretory System, a "syringe" that allows bacteria to infect other cells.

Argumentum ad Ignorantiam

No potential example of a supposed irreducibly complex system can, even in theory, demonstrate that it did not evolved from less complex components. One can only demonstrate how a system can be reduced, or claim ignorance as to how it can be. Irreducible complexity is therefore an argument from ignorance and, more specifically, a God of the gaps argument.

Falsifiability

Irreducible complexity is not falsifiable. Demonstrating how a complex system can be reduced to less complex components only shows the apologist to be wrong on that particular example. Each 'reduced' component is, in turn, another system susceptible to the same claim of being irreducibly complex, ad infinitum.

See also

External links


v · d Science
v · d General science
Scientific method   Scientific theory · Hypothesis · Evidence · Examining claims · Skepticism
Scientific Disciplines   Physics · Biology · Chemistry · Psychology · Medical Science · Mathematics
History of science   Library of Alexandria · Aristotle · Dark ages · Renaissance · The enlightenment · Heliocentrism · Newtonian physics · Darwinian evolution · Mendelian genetics · Relativity Theory · Quantum mechanics · Space exploration · Computer sciences · String theory
Champions of reason   Carl Sagan · Karl Kruszelnicki · Julius Sumner Miller · John Allan Paulos · James Randi
v · d Biology
Evolution   Overview of genetics · Genetic mutation · Hereditary change · Natural selection · Adaptation
Abiogenesis   Possible theories of abiogenesis · Building blocks of life · The Urey-Miller experiment
Evolutionary straw men   Life just exploded from nothing · So you think we came from monkeys · How did the first dog find a mate · Crocoducks · Banana argument · 747 Junkyard argument · Irreducible complexity · Chuck Missler's jar of peanut butter · What good is half a wing?
Notable Biologists   Charles Darwin · Alfred Russel Wallace · Thomas Huxley · Gregor Mendel · Stanley Miller · Norman Borlaug · Richard Lenski · Jerry Coyne · Richard Dawkins · PZ Myers
Notable quacks   William Dembski · Michael Behe · Geoffrey Simmons · Ken Ham · Michael Cremo
v · d Physics
Cosmology   Big bang · Relativity theory · The cosmos · Black holes
Quantum mechanics   Heisenberg Principle · Schrödinger's cat · Atomic decay
Physics straw men   Fine-tuning argument · Anthropic principle · Quantum mechanics and free will · Quantum mechanics and the after life · Quantum mechanics and Naturopathy · Something can't come from nothing
Notable Physicists   Plato · Isaac Newton · Albert Einstein · Maxwell Plank · Niels Bohr · Werner Heisenberg · Richard Feynman · Erwin Schrödinger · Freeman Dyson · Roger Penrose · Neil deGrasse Tyson · Stephen Hawking · Micho Kaku
Notable Quacks   Dinesh D'Souza · Ray Comfort
v · d Mathematics
Mathematics   Overview of mathematics · Numbers in reality · History of numbers
Statistics   Sample size · Selection bias · Data mining · Standard divination · Statistical significance · Statistical probability · Meta probability · Gambler's fallacy
Mathematics in nature   Golden ratio · Golden spiral · Fibonacci sequence
Mathematics and religion   Biblical value of pi · Noah's flood
Personal tools
Namespaces
Variants
Actions
wiki navigation
IronChariots.Org
Toolbox