Various ancient Greek (and Roman) thinkers espoused presuppositions which came to bear heavily on origins science. The first was the eternal universe, which provided a logical basis for understanding existence. Another was spontaneous generation, which held that life regularly emerged from non-living matter. Both these presuppositions survived the end of the Greek empire and were passed down to successor civilizations, including our own.
With the presupposition of spontaneous generation in place, the remaining explanatory task, as the Greeks saw it, was to develop a plausible explanation for the emergence of higher life forms. In other words, if the biological starting point was, for example, small bugs which sprang into life in stagnant water, or maggots on animal carcasses, how did larger, more complex life forms come into being? The Greeks reasoned that the higher life forms must have evolved from the lower. This line of reasoning was very understandable given the presuppositions the Greeks were working with.
The Greeks did not produce scientific papers in the contemporary sense, but musings, sometimes couched in poetry, which revealed their thinking. For example, the Greek philosopher Anaximander spoke of man as “like another animal, namely, a fish, in the beginning”.[1] This brief statement, which was provided without evidentiary support, is nonetheless considered to be “well-nigh akin to prevision of the mutability of species, and of what modern biology has proved concerning the marine ancestry of the highest animals.” That was the opinion, at least, of British writer Edward Clodd (1840–1930), a committed Darwinist. Clodd provided a brief introduction, then summarized Greek origins musings into 10 main points in his 1897 book Pioneers of Evolution: from Thales to Huxley. He also added a brief italicized comment to each based on his understanding of science at the time. We quote Clodd at length:
Standing well-nigh on the threshold of the Christian era, we may pause to ask what is the sum of the speculation into the causes and nature of things which, begun in Ionia (with impulse more or less slight from the East, in the sixth century before Christ), by Thales, ceased, for many centuries, in the poem of Lucretius, thus covering an active period of about five hundred years. The caution not to see in these speculations more than an approximate approach to modern theories must be kept in mind.[2]
(For our present purposes we skip the first six points of Clodd’s summary and present the final four points which are directly relevant to Greek origins thought.[3] Clodd presents a summary statement of Greek origins, then provides additional thoughts below each statement in italics.)
7. Life arose out of non-living matter.
Although modern biology leaves the origin of life as an insoluble problem, it supports the theory of fundamental continuity between the inorganic and the organic.
8. Plants came before animals: the higher organisms are of separate sex, and appeared subsequent to the lower.
Generally confirmed by modern biology, but with qualification as to the undefined borderland between the lowest plants and the lowest animals. And, of course, it recognises a continuity in the order and succession of life which was not grasped by the Greeks. Aristotle and others before him believed that some of the higher forms sprang from slimy matter direct.
9. Adverse conditions cause the extinction of some organisms, thus leaving room for those better fitted.
Herein lay the crude germ of the modern doctrine of the ‘survival of the fittest’.
10. Man was the last to appear, and his primitive state was one of savagery. His first tools and weapons were of stone; then, after the discovery of metals, of copper; and, following that, of iron. His body and soul are alike compounded of atoms, and the soul is extinguished at death.
The science of Prehistoric Archaeology confirms the theory of man’s slow passage from barbarism to civilisation; and the science of Comparative Psychology declares that the evidence of his immortality is neither stronger nor weaker than the evidence of the immortality of the lower animals.
Clodd’s seventh point refers to spontaneous generation, and the eighth through tenth points are clearly recognizable as an evolutionary scheme, even if they lack, as they must, the Darwinian mechanism. In fact, this is the thesis of Clodd’s book: evolutionary thinking has progressed from Thales (d. 548 BC) to Thomas Huxley (1825–1895), interrupted only, in Clodd’s view, by the lamentable rise of Christianity. This halted development for around 1500 years, as Clodd explains in Part 2 of the book, titled The Arrest of Inquiry— A.D. 50–A.D. 1600.
The Greeks had apparently provided a template for non-theistic biological origins which was to last for 2400 years. This template comprised spontaneous generation as a starting point, and evolutionary processes to explain the emergence of higher life forms.
But spontaneous generation came under increasing scrutiny as the centuries passed. In 1668, Italian philosopher Francesco Redi experimented with varieties of meat and fish in covered and uncovered jars. Redi’s observation that maggots did not appear on the covered meat counted against spontaneous generation, and scientists began to believe that, at most, it was limited to “parasitic worms and microorganisms”.[4] In 1765, another Italian, Lazzaro Spallanzani, carried out experiments that appeared to refute spontaneous generation and published his results. These were questioned by Irish priest John Needham, whose own experiments appeared to support spontaneous generation.[5] The debate continued.
By the late eighteenth century, Charles Darwin’s grandfather Erasmus Darwin made his contribution to evolutionary theory. Perhaps influenced by the ancient Greeks, he expressed his ideas in poetic form.[6] Erasmus believed that organisms had the power to adapt themselves over many generations; that all life descended from a primordial life form, which he termed the “filament”, and that evolutionary processes were slow.
Erasmus Darwin’s ideas anticipated those of Jean-Baptiste Lamarck (1744–1829). Lamarck espoused the “theory of inheritance of acquired characteristics”. For example, imagine two herds of deer, one on an island without any natural predators, and another in a different geographic location inhabited by predators. The deer subject to predation would spend more time running than those on the island, resulting in a leaner build with a more highly developed cardiovascular system. These acquired characteristics, in Lamarck’s view, would be passed on to the offspring. Over time, the herd would become considerably more suited to running than the island-based deer. Again, Lamarck followed the template provided by the Greeks—spontaneous generation as a starting point, and an evolutionary mechanism to explain diversity.
[1] Clodd, 1907, p. 7.
[2] Ibid., pp. 29–30.
[3] Ibid., pp. 30–32.
[4] Strick, 2000, p. 4.
[5] Ibid., p. 6.
[6] For example, these lines from Erasmus Darwin’s poem “Organic Evolution” describe spontaneous generation:
Hence without parent, by spontaneous birth,
Rise the first specks of animated earth;
From Nature’s womb the plant or insect swims,
And buds or breathes, with microscopic limbs. (Darwin, 2024).