Editing Spontaneous generation (section)

{{Short description|Theory of life arising from non-living matter}}
{{About|historical theories on the ongoing emergence of life|the origin of life|Abiogenesis}}
{{Good article}}
{{Use dmy dates|date=January 2022}}

[[File:Spontaneous Generation of Seashells.svg|thumb|upright=1.35|Spontaneous generation of seashells, according to [[Aristotle]], varied with the nature of the seabed. Slime gave rise to [[oyster]]s; sand, to [[scallop]]s; and the hollows of rocks, to [[limpet]]s and [[barnacle]]s. People kept on wondering, though, whether the eggs of these animals might not be central to the generation process.<ref name="Bondeson 2018">{{cite book |last=Bondeson |first=Jan |title=The Feejee Mermaid and Other Essays in Natural and Unnatural History |chapter=Spontaneous Generation |publisher=[[Cornell University Press]] |publication-place=Ithaca, New York |date=31 December 2018 |doi=10.7591/9781501722271-009 |pages=193–249|isbn=9781501722271 }}</ref>]]

'''Spontaneous generation''' is a [[Superseded scientific theories|superseded scientific theory]] that held that living creatures could arise from [[abiotic component|non-living matter]] and that such processes were commonplace and regular. It was [[Hypothesis|hypothesized]] that certain forms, such as [[flea]]s, could arise from inanimate matter such as dust, or that [[maggot]]s could arise from dead flesh. The [[doctrine]] of spontaneous generation was coherently synthesized by the Greek philosopher and naturalist [[Aristotle]], who compiled and expanded the work of [[Pre-Socratic philosophy|earlier natural philosophers]] and the various ancient explanations for the appearance of [[organism]]s. Spontaneous generation was taken as scientific fact for two millennia. Though challenged in the 17th and 18th centuries by the experiments of the Italian biologists [[Francesco Redi]] and [[Lazzaro Spallanzani]], it was not discredited until the work of the French chemist [[Louis Pasteur]] and the Irish physicist [[John Tyndall]] in the mid-19th century.

Among biologists, rejecting spontaneous genesis is no longer controversial. Experiments conducted by Pasteur and others were thought to have refuted the conventional notion of spontaneous generation by the mid-1800s. Since all life appears to have [[Common descent|evolved from a single form]] approximately four billion years ago, attention has instead turned to the [[abiogenesis|origin of life]].