Who Was Cotton Mather? Brilliant Scientist, Misguided Minister

By Karen Harris

Circa 1710, Cotton Mather (1663-1728). American Congregational clergyman. Source: (Photo by Stock Montage/Getty Images).

In Puritan New England in the 1690s, there were two things that struck fear into the hearts of the people—smallpox and witchcraft. For one colonial American minister, scientist, author, and leader, both of these fears would define his life. He is Cotton Mather, one of the most brilliant minds of his era with progressive views on disease control. Yet his strict religious views and fear of the devil led him to condone the hysteria of the Salem Witch Trials. 

Harvard University. Source: (founderspatriots.org)

Cotton Mather, the Early Years

Cotton Mather was born on February 12, 1663, to a prominent family in colonial Massachusetts. His father, Increase Mather, was the president of Harvard University. Like his father before him, Cotton Mather was a diligent and dedicated scholar. By the time he was 12 years old, he has mastered both Greek and Latin. At age 18, he had earned a master’s degree from Harvard. 

Source: (smallpoxinoculation.wordpress.com)

A Distinguished Scientist

Cotton Mather was an early proponent of inoculating the population against smallpox. A voracious reader, Mather read about inoculation practices that were developed in Asia sometime between the 8th and 10th centuries. Inoculating differs from vaccinating in that the person is purposely infected with smallpox from a person who has a mild form of the disease. The body then develops its natural defenses against this mild form of smallpox, building up immunity to the disease and, thus, protecting the person from subsequent infections. To others in Massachusetts, it sounded crazy to intentionally give someone a deadly disease. But the Mather, the science behind smallpox inoculations made sense. To proof his point, Mather even inoculated his own son against smallpox. The boy grew terribly ill and almost died, but he pulled through and was protected from further smallpox infections. 

Royal Society of London. Source: (xlsemanal.com)

London’s Royal Society

As an advocate for smallpox inoculation, Cotton Mather wrote numerous books and papers on the subject. He kept meticulous records of people he inoculated and observed them through some of the smallpox epidemics that swept through New England in colonial times. The work that Mather did help to prove the effectiveness of the smallpox inoculations. In 1724, Mathers was elected into London’s Royal Society, a distinguished group of notable scientists. 

North Church. Source: (bostonreapartyship.com)

A Religious Leader

Cotton Mather studied the Bible with as much diligence as he studied scientific tomes. He became a minister, like his father and grandfather. Ordained in 1685, he served at Boston’s North Church for more than forty years. In addition to authoring medical and science books, Mather wrote religious papers and books as well. According to his personal journals, Mather spent much of his life in internal worry that his soul would be condemned to hell.

Salem Witch Trials. Source: (pri.org)


Cotton Mather wholeheartedly believed in witches. In 1689—four years before the Salem Witch Trials began—he published a book titled Memorable Providences Relating to Witchcraft and Possession. This book was well-received and may even have planted some seeds about witchcraft in the minds of people in Massachusetts. In his work, and in his sermons, Mather was adamant that people who enter into a compact with the Devil need to be severely punished. 

Source: (history.com)

Witches in Salem

In 1692 and 1693, some of the citizens of Salem, Massachusetts, began exhibiting strange behavior that was attributed to witchcraft. Very quickly, mass hysteria gripped the community, with accusations of witchcraft running rampant. More than 200 people were accused of being witches. Nineteen people—fourteen women and five men—were tried and executed for witchcraft. 

Source: (bbc.com)

Mather’s Influence on the Witch Trails

Early in the Witch Trials, Mather advocated allowing the courts to admit spectral evidence in witchcraft cases. Spectral evidence, Mather stated, was the testimony of disembodied spiritual entities who spoke through others, usually the victims of witchcraft. Today, we realize that this opened the door for people with grudges or vendettas against others to give false testimony that the courts would have to admit. Although Mather later backpedaled on his push for spectral evidence, some historians believed it was his way of trying to distance himself from the mass hysteria of the Salem Witch Trials. Mather did not participate in the Salem Witch Trials, but he did write letters to judges and magistrates presenting his opinion on the cases, influencing the beliefs of the judges. 

Pirate WIlliam Kidd. Source: (newhistorian.com)

And, Also Pirates

Cotton Mather wasn’t just battling against smallpox and witchcraft. He also had a beef against pirates. He wrote numerous works and preached sermons on the evils of pirates. He believed that pirates were doing the devil’s work and were almost as evil as witches. Cotton Mather was invited to preach at the trials of several notable pirates, including John Quelch, William Fly, Samuel Bellamy, and William Kidd. In his time, Cotton Mather wrote more than 400 books. Many of them were studies in human nature, particularly the idea of good versus evil. 

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Karen Harris


Karen left the world of academic, quitting her job as a college professor to write full-time. She spends her days with her firefighter husband and four daughters on a hobby farm with an assortment of animals, including a goat named Atticus, a turkey named Gravy, and a chicken named Chickaletta.