Spontaneous Generation: Then & Now

Aristotle: Spontaneous Generation

Recently, in an attempt to debunk the theory of evolution a naysayer noted to me the absurdity of logs turning into alligators. Agreed! However, that assertion lead to the conclusion that life must have originated only by Creation. The logic stems from a (mis)understanding of Aristotle’s theory of spontaneous generation. Having studied Classics in university I hadn’t come across Aristotle claiming that this theory applied to any organism more complicated than testacea, insects, certain fish and plants. Consequently, I’ve been poring over the literature about this theory and I’ve come to the realization that it is far more complicated than I remembered!

The premise of the theory is the idea that life could rise from a nonliving source; it was referred to as generatio spontanea (Latin) or to apo tautaomatou (Greek, “things generated by spontaneity”) or spontaneous generation, in which “spontaneous” is used in the context of “growing naturally, without being planted, as in the Latin roote sponte, “of its own” (the Greek equivalent being automaton).[1] For the most part, ancient Greeks, including Aristotle, held that most animals were created without parents of their own kind. Thus, Aristotle tackled the question of how species could consistently be created spontaneously, in which it develops from matter (mud, dirt, or putrefied material) that is in no way similar to the created organism.[2] Yet, even though he was a proponent of the theory, it was inconsistence with his metaphysical doctrines of causation and chance. However, the theory is antiquated and was scientifically disproved by the 19th Century French chemist and microbiologist Louis Pasteur, and the general consensus is that this theory is obsolete.

Yet Aristotle was not the only Greek philosopher to uphold and expand upon this theory. Pre-Aristotelian philosophers who held similar theories include Anaximander (believed everything arose out of the elemental nature of the universe: the “apeiron” or “unbounded”); Anaximenes (speculated there was a primordial terrestrial slime, a mixture of earth and water, which when combined with the sun’s heat formed plants, animals and humans); Xenophanes (traced human origins to the transition period between the fluid stage of earth and the formation of land and held that spontaneous generation was influenced by the sun); Empedocles accepted the theory  but held that there had to be trials of combinations of parts of animals that arose); Anaxagoras (adopted the terrestrial slime account, but he believed that the seeds of plants existed in the air from the beginning, and of animals in the aether (a material that fills the region of the universe above the terrestrial sphere).


Even though the theories of these philosophers are discounted are not considered viable, they are not completely far off from accepted theories today about the origins of life. Abiogenesis is “the natural process by which life arose from non-living matter such as simple organic compounds.” Also, Aristotle did not argue that putrefaction was not the source of life, but the byproduct of the action of the “sweet” element water. Also, there is of course modern day theories the chemical reactions occurring in aerosol droplets where small molecules combine into larger ones  and “could have nurtured the earliest building blocks of life” (Inside Science). Or perhaps it was the ever-changing atmospheric conditions of life or around those volcanic vents at the bottom of the ocean or… and so forth (Universe Today).

So, in effect, Aristotle’s theory that living organisms such as testacea, insects, certain fish and plants could have developed from non-living matter (containing pneuma, or “vital heat”), combined with the sun’s pneuma (“vital heat”) is actually somewhat close to current theories about the origin of life.

Moral of the story? If we look carefully at different theories around specific questions, we can see that even though the surface of the theories seem to be completely contrasted the foundations might be quite close. So let’s not automatically assume that a theory holds no merit based on one (incorrect in this case) assumption about it and recognize that it’s important to respect and to keep an open mind about and other peoples’ ideas and opinions. Cool?

Life Map.

[1-2]. Jan Klein, Norman Klein, Solitude of a Humble Genius (Berlin, Heidelberg: Springer Berlin Heildeberg, 2013), 29-30.
[3] S.M. Connel, “Aristotle and Galen on Sex Difference and Reproduction”, Studies in History and Philosophy of Science, Vol. 33, Issue 3, pp. 417.

Image credits:
Aristotle: Associate’s Mind
Origin of Life: NASA