Two frequently cited examples of foolish ideas that were once quite popular are spontaneous generation and eugenics. We now know that maggots and mice don’t spontaneously arise in meat and grain, and that trying to improve the human race through controlled breeding is a dangerous idea.
These ideas are ridiculed today, but they were once supported by intelligent and even illustrious individuals—and not without good reason.
Spontaneous generation was the rational alternative to biblical creation and the perfect complement to Charles Darwin’s theory of evolution. Supporters of spontaneous generation said that given the proper raw materials and environmental conditions, life arises as the result of natural processes.
Eugenics was also a natural outgrowth of evolution. If humans and other species are the result of ongoing evolution, then we must learn as much as we can about the process, and apply that knowledge to the benefit of individuals and society. That was certainly the intention of early enthusiasts such as Alexander Graham Bell.
What brought these ideas into disrepute? Belief in spontaneous generation was an obstacle to understanding the spread of disease-causing germs. The fiercely conservative Louis Pasteur used swan-necked flasks to show that microbes do not arise spontaneously. He influenced Joseph Lister, the developer of antiseptic surgery. And Eugenics is now associated with racial discrimination, forced sterilization, and genocide.
It’s easy to portray these ideas as silly or immoral, but neither has been totally rejected. Scientists have shown that simple organic molecules can be created from inorganic substances. Genetic screening, counseling, and abortion are now common practices.