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Period: 300 to
300 BC to 1900 AD
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350
Aristotle
Aristotle wrote The History of Animals. It writes that spontaneous generation is seen with vegetables, many insects, and more. He claimed that grub spontaneously generated from fire, and worms from snow. This theory concerned pneuma-vital heat. Vital heat lived within substances so that it had the power to generate new life. -
520
Anaximander
Anaximander was a Greek philosopher who believed that everything was generated from the elemental nature of the universe. For example, he argued that wet or liquid environments, when combined with sun, formed living creatures. (Anaximander lived in an earlier time than Aristotle, though this is not an option on Timetoast). -
Jan Baptist van Helmot
Helmot published a study concerning an experiment he conducted with willows. After five years, the willow tree grew, and the soil that the tree was supposed to be getting mass from didn’t decrease notably. Therefore, he concluded the extra mass of the tree was spontaneously generated. -
William Harvey
In 1651, William Harvey published Exercitationes de Generatione Animalium (On the Generation of Animals), in which he denounced spontaneous generation. Instead of supporting it, he suggested that all animals originally came from an egg, with even maggots and worms having some origin with eggs. -
Francesco Redi
In 1668, Francesco Redi conducted an experiment, attacking spontaneous generation. He disproved the theory that maggots arise from dying meat, and showed that they in fact come from fly larvae on the meat. This was an immense catastrophe for spontaneous generation advocates. -
John Needham
In 1745, John Needham conducted a series of experiments that supposedly supported spontaneous generation with boiled broths. It was believed that if the broth were boiled, all living organisms would be killed. However, even after it had been boiled and sealed, it still clouded. This was an alleged sign of spontaneous generation to him. -
Lazzaro Spallanzani
Lazzaro Spallanzani made changes to Needham’s experiment, as he believed that Needham allowed the broth to be contaminated when open. He modified it so that the broth boiled while sealed. His findings went against spontaneous generation. However, opposition claimed he’d only proved generation couldn’t take place without air. -
Johann Wolfgang von Goethe
Johann Wolfgang von Goethe began conducting experiments concerning spontaneous generation. He worked with bits of plants that he soaked in water and sealed in containers. Then, he would observe as microscopic animalculae “arose” from the plants. He, like many others, believed in spontaneous generation. -
Charles Cagniard de la Tour and Theodor Shwann
Charles Cagniard de la Tour and Theodor Shwann published their discovery of yeast in alcoholic fermentation. They examined the foam left after the brewing process. They noticed tiny organisms, and concluded that the beer wouldn’t brew if yeast was absent. This proved spontaneous generation wasn’t present in the process. -
Louis Pasteur
His experiment proved no life would spontaneously arise from an organism when exposed to air. He boiled broth so all organisms were killed, and bent the flask to an S shape. This prevented organisms from entering, yet let air flow, and the broth remained unchanging. This demonstrated spontaneous generation’s falseness.
