It was a commonly held belief in Ancient Rome, during the Middle
Ages, and even until the late nineteenth century that spontaneous
generation, or the sudden generation of complex life from nonliving matter,
existed. (Evers, 1999) Scientists began to question this theory as early
as the second half of the seventeenth century, but it was not until almost
200 years later that Louis Pasteur definitively disproved spontaneous
generation and changed the course of scientific thought. While it is still
debated whether any forms of Abiogenesis, or the generation of even simple
or microscopic life from nonliving matter, could be possible (Wilkins,
2004), it is certain that spontaneous generation involving complex life
The first recorded Westerner to suggest spontaneous generation was
Anaximander, a philosopher from the BC 600's and 500's. His pupil,
Anaximenes, wrote that air imparted life, motion, and thought. Xenophanes
and Parmenides thought that plants and animals would spontaneously form
under sunlight. Empedocles wrote in the BC 400's that spontaneous
generation is possible if there are the correct combinations of parts of
animals to rise. (Wilkins, 2004) Aristotle, in the times of Ancient
Greece, believed that life was the result of the ether, a substance which
existed only in the heavens, combining with the pneuma, or the animating
force or soul, and that if the pneuma was present, it would be possible for
life to come from nonliving material. (Wilkins, 2004)
In 1668, Francesco Redi, a physician and poet, attacked the idea of
spontaneous generation. In his famous experiment, he set out meat in a
variety of flasks, some of which were completely open, others covered with
a gauze or mesh material, and others were sealed off completely. When
maggots appears only on the meat which was exposed to the air, and
therefore to flies, his theory that maggots came fro...