Editing Orthogenesis (section)

==Definition==
[[File:Theodor Eimer (Professorengalerie Universität Tübingen).jpg|thumb|upright|[[Theodor Eimer]]]]
{{further|Teleology in biology}}

The term orthogenesis (from Ancient {{langx|el|ὀρθός}} orthós, "straight", and Ancient {{langx|el|γένεσις génesis}}, "origin") was first used by the biologist [[Wilhelm Haacke]] in 1893.<ref name=LevitOlsson2006/><ref name="Gould 2002">{{cite book |last=Gould |first=Stephen Jay |author-link=Stephen Jay Gould |date=2002 |title=The Structure of Evolutionary Theory |publisher=Harvard University Press |pages=[https://archive.org/details/structureofevolu00goul/page/351 351–352] |isbn=978-0-674-00613-3 |title-link=The Structure of Evolutionary Theory }}</ref> [[Theodor Eimer]] was the first to give the word a definition; he defined orthogenesis as "the general law according to which evolutionary development takes place in a noticeable direction, above all in specialized groups".<ref name="Lane 1996">{{cite book |last=Lane |first=David H. |date=1996 |title=The Phenomenon of Teilhard: Prophet for a New Age |publisher=Mercer University Press |pages=60–64 |isbn=978-0-86554-498-7}}</ref>

In 1922, the zoologist [[Michael F. Guyer]] wrote:

{{quote|[Orthogenesis] has meant many different things to many different people, ranging from a mystical [[inner perfecting principle]], to merely a general trend in development due to the natural constitutional restrictions of the germinal materials, or to the physical limitations imposed by a narrow environment. In most modern statements of the theory, the idea of continuous and progressive change in one or more characters, due according to some to internal factors, according to others to external causes-evolution in a "straight line" seems to be the central idea.<ref>{{cite journal |last=Guyer |first=Michael F. |date=1922 |jstor=2456504 |title=Orthogenesis and Serological Phenomena |journal=The American Naturalist |volume=56 |issue=643 |pages=116–133 |doi=10.1086/279852|doi-access= }}</ref>}}

According to [[Susan R. Schrepfer]] in 1983:

{{quote|Orthogenesis meant literally "straight origins", or "straight line evolution". The term varied in meaning from the overtly vitalistic and theological to the mechanical. It ranged from theories of mystical forces to mere descriptions of a general trend in development due to natural limitations of either the germinal material or the environment&nbsp;... By 1910, however most who subscribed to orthogenesis hypothesized some physical rather than metaphysical determinant of orderly change.<ref>{{cite book |last=Schrepfer |first=Susan R. |author-link=Susan Schrepfer |date=1983 |title=Fight to Save the Redwoods: A History of the Environmental Reform, 1917–1978 |publisher=University of Wisconsin Press |pages=81–82 |isbn=978-0-299-08854-5}}</ref>}}

In 1988, [[Francisco J. Ayala]] defined progress as "systematic change in a feature belonging to all the members of a sequence in such a way that posterior members of the sequence exhibit an improvement of that feature". He argued that there are two elements in this definition, directional change and improvement according to some standard. Whether a directional change constitutes an improvement is not a scientific question; therefore Ayala suggested that science should focus on the question of whether there is directional change, without regard to whether the change is "improvement".<ref name=":1">{{cite book |last=Ayala |first=Francisco J. |author-link=Francisco J. Ayala |year=1988 |chapter=Can progress be defined as a biological concept? |title=Evolutionary Progress |editor=Nitecki, M. |pages=75–96 |publisher=University of Chicago Press |isbn=978-0-226-58693-9}}</ref> This may be compared to [[Stephen Jay Gould]]'s suggestion of "replacing the idea of progress with an operational notion of directionality".<ref name=":2">{{cite book |last=Gould |first=Stephen Jay |author-link=Stephen Jay Gould |date=1997 |title=Full House: The Spread of Excellence from Plato to Darwin |publisher=Harmony |isbn=978-0-609-80140-6 |url=https://archive.org/details/fullhouse00step }}</ref>

In 1989, [[Peter J. Bowler]] defined orthogenesis as:

{{quote|Literally, the term means evolution in a straight line, generally assumed to be evolution that is held to a regular course by forces internal to the organism. Orthogenesis assumes that variation is not random but is directed [[Teleology in biology|towards fixed goals]]. Selection is thus powerless, and the species is carried automatically in the direction marked out by internal factors controlling variation.{{sfn|Bowler|1989|pages=268–270}}}}

In 1996, [[Michael Ruse]] defined orthogenesis as "the view that evolution has a kind of momentum of its own that carries organisms along certain tracks".{{sfn|Ruse|1996|page=261}}