Where does life come from? The first chapter of Genesis describes life being created by God, who instructs living things to “be fertile and multiply” and fill the seas and land. But for much of history, scientists thought life came from the Earth itself. This idea dated back to at least Aristotle, 2,500 years ago. It said that matter possesses life-generating power. Small creatures could be spontaneously generated straight from dirt. People claimed to have seen frogs forming from mud. The poet Ovid wrote:
Dirt has his seed engendering frogs full green,
Yet so as feetless and without legs on earth they lie,
So as a wonder unto passers-by is seen,
One part has life, the other earth full dead is nigh.
The ancient Jewish Scripture commentary, the Mishnah, discusses whether dirt that generates a mouse would be unclean, since Leviticus 11:29 declares mice unclean. The ancient writer Lucretius, who claimed that the universe itself formed spontaneously from randomly moving elementary particles, said that human beings themselves were spontaneously generated. We don’t see that happen now, he said, because Earth’s life power has been depleted. Now only small, low creatures are spontaneously generated. People even published recipes for how to generate mice!
But some questioned the theory of spontaneous generation. One was Antony van Leeuwenhoek, who lived in the late 17th century. He was one of the first people to build powerful microscopes and to discover things like bacteria. Leeuwenhoek was amazed by the beauty and complexity with which God endowed the microscopic world: “In all the observations I have made, we can clearly see the incomprehensible perfection, the exact order, and the inscrutable providential care with which the most wise Creator and Lord of the Universe, has formed the bodies of these little creatures, which are so minute as to escape our sight.”
Leeuwenhoek’s observations also convinced him that tiny creatures were not spontaneously generated. And if he could see tiny worms giving birth to young, for example, why should he think any creature would spontaneously generate?
Leeuwenhoek was right, but the theory of spontaneous generation endured. For example, in 1884, two centuries after Leeuwenhoek, the German botanist Carl Nageli proposed that single-cell organisms could be spontaneously generated.
Today scientists believe that all living things are fertile and multiply. Nothing just spawns from the mud. Not single cells. Not microscopic worms. Not frogs. Not mice. And not people.
That is good. The spontaneous generation theory leaves open a door to some ugly ideas. Lucretius also said that Earth randomly spawned countless monsters — headless or mouthless creatures that could not survive. Spontaneous generation allows for the possibility that some people are true human beings, while others are inherently lesser — the descendants of monstrosities. Genesis, by contrast, says all people are of one family, all “sons of Adam and daughters of Eve” (in the words of C.S. Lewis).
Science today agrees that all people are of one family. If, because of something you heard about Galileo or Darwin, you think that science conflicts with religion, reconsider. The challenges science has posed to Genesis regarding details of where the Earth is (Galileo) or how the one human family came to be (Darwin) are minor quibbles compared to science’s rejection of spontaneous generation.
Chris Graney lives in Louisville and writes for the Vatican Observatory’s “Sacred Space Astronomy” blog.