Definition of evolution
The definition of evolution is itself part of the controversy over evolution. Several different meanings have been and still are used. Creationists charge that evolutionists often equivocate between different meanings[1], while evolutionists acknowledge that not clearly defining the term leads to confusion.[2]
Definitions
The word evolution comes from Latin, meaning unrolling[3], and refers to any gradual change. But it has more precise definitions in popular and scientific use.
Universal
The broadest definition, change in the history of the universe, includes biological change, and non-biological change, such as galaxy formation. Theodosius Dobzhansky (1900-1975) said, "Evolution comprises all the stages of the development of the universe: the cosmic, biological, and human or cultural developments. Attempts to restrict the concept of evolution to biology are gratuitous."[4]
Development of life
Kerkut defined evolution as "the theory that all the living forms in the world have arisen from a single source which itself came from an inorganic form"[5]
As stated, this includes the origin of life (abiogenesis), but evolutionists today generally reject that evolution includes abiogenesis, as Natural selection can only operate once life has started.
Instead, it is defined as the development of life from some last universal common ancestor, from which all plants, animals, fungi, and other life on Earth are directly descended.
Webster's dictionary put it as, "...the development of a species, organism, or organ from its original or primitive state to its present or specialized state; phylogeny or ontogeny"[6]
Although it has been criticised on a number of grounds[7], this is the main concept behind the definition provided by the Oxford Concise Science Dictionary: "The gradual process by which the present diversity of plant and animal life arose from the earliest and most primitive organisms, which is believed to have been continuing for the past 3000 million years".[6]
In an attempt to clearly and concisely clarify which definition they are using, creationists sometimes refer to this defintion with terms such as "goo-to-you" evolution[8], "molecules-to-man" evolution,[9] or "fish-to-philosopher" evolution[10].
It is primarily evolution of this definition that creationists disagree with.
Gene frequency
In modern scientific use, it is often defined as a change in gene frequency
E.O. Wilson defines evolution as "any change in gene frequency in a population." Helena Curtis and N. Sue Barnes define evolution as "any change in the frequency of alleles within a gene pool from one generation to the next"[6]
Creationists object that this definition is used to demonstrate trivial changes that are then used to claim that the entire development of life definition has been demonstrated.[11] This definition has also been criticised by Ernst Mayr[12]
The "gene frequency" definition avoids the distinction between microevolution and macroevolution - a distinction which is important to anti-evolutionists.
Use of different definitions
When evolution is defined as "the gradual appearance of new forms of life" over geological time, then Americans are split 50-50 over it has really occurred.
About 45% of Americans are Young Earth Creationists.
Advocates for the teaching of evolution as a finding of mainstream science tend to use two different meanings of "evolution".
- We have fossil evidence for evolution. It's a fact. (teacher in CNN article)
This apparently refers to the assertion that the appearance of new forms of life is supported by fossils (see carbon dating). But the context of the quote implies that the teacher was actually talking about the notion that "new species can evolve from older ones -- such as humans evolving from ancient apes." [1]
About half of the people who reject the materialist Theory of Evolution accept the fossil evidence of "gradual appearance" while rejecting mainstream biology's explanation that natural selection and unguided forces like mutation and copying errors is the cause.
Facts are observations, theories are models which explain those observations. Theories can never be facts, because that implies that the model itself is an observation. However, theories may often become so well-accepted and well-proven that they rise to a level at which scientists are comfortable calling them "facts" - an example is the theory of relativity, or the theory of particle/wave duality.
Notes
- ↑ See, for example, Definitions as slippery as eels in Who’s really pushing ‘bad science’?, by Jonathan Sarfati.
- ↑ What is Evolution? by Laurence Moran.
- ↑ [http://www.askoxford.com/concise_oed/evolution?view=uk AskOxford.com.
- ↑ Quoted by Stephen E. Jones at http://members.iinet.net.au/~sejones/evolut01.html
- ↑ Implications of Evolution, p. 157, by Kerkut, G.A., quoted in Origin of life and the homochirality problem: is magnetochiral dichroism the solution? by Jonathan Sarfati.
- ↑ 6.0 6.1 6.2 Quoted in What is Evolution, by Laurence Moran.
- ↑ Laurence Moran on Talk.Origins criticises the definition for excluding prokaryotes, protozoa, and fungi, and for specifying gradual changes, and other reasons.
- ↑ For example, 15 ways to refute materialistic bigotry, by Jonathan Sarfati.
- ↑ For example, Speedy species surprise, by David Catchpoole and Carl Wieland, Creation vol. 23 No. 2, p. 13.
- ↑ For example, footnote 1 in Professing creation, by Carl Wieland and Jonathan Sarfati, Creation vol. 22 No. 1, p. 36.
- ↑ Refuting Evolution 2, by Jonathan Sarfati, chapter 3.
- ↑ Referred to in CMI misunderstands evolution?.