[[Image:Image002Evolution.jpg|alt=evolution darwin theory|right|thumb|225px|Late in [[Charles Darwin|Charles Darwin's]] life, Darwin told the Duke of Argyll that he frequently had overwhelming thoughts that the natural world was the [[Intelligent design|result of design]].<ref>http://plato.stanford.edu/entries/teleological-arguments/notes.html</ref> In a letter to [[Asa Gray]], Darwin confided: "...I am quite conscious that my speculations run quite beyond the bounds of true [[science]]."<ref>http://www.darwinproject.ac.uk/entry-2109</ref>]]
The theory of '''evolution''' is a [[Naturalism|naturalistic]] [[theory]] of the [[history]] of life on earth (this refers to the theory of evolution which employs [[methodological naturalism]] and is taught in schools and universities). Merriam-Webster's dictionary gives the following [[definition of evolution]]: "a theory that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations..."<ref>[http://www.m-w.com/dictionary/evolution Merriam-Webster's Online Dictionary, Definition for "evolution"]</ref> Currently, there are several [[theories of evolution]].