Mario Livio Ph.D.


Did Curiosity Really Kill the Cat?

Curiosity is the best remedy for fear.

Posted Sep 17, 2020

We are all familiar with the common proverb “Curiosity killed the cat,” but what was the origin of that proverb, and did it really intend to suppress curiosity?

Interestingly, the original version was “care killed the cat,” with the word “care” referring to grief or worry. In this form, the proverb first appeared in print at the end of the sixteenth century, first in a play by playwright Ben Johnson (in 1598), and about a year later in Shakespeare’s Much Ado About Nothing. It was still quoted in this form at the end of the nineteenth century, in Brewer’s Dictionary of Phrase and Fable. So what happened? How did “care” get replaced by “curiosity?”

As far as I can tell, nobody knows. The first known printed reference to this version was in an Irish newspaper in 1868, and it started appearing more frequently as a proverb in 1873. Be that as it may, there is no question that the cautionary expression meant to serve as advice suggesting that it is best to mind one’s own business.

This would not have been the first time for curiosity to be discouraged. All civilizations built, at some point, walls around certain types of knowledge. Adam and Eve were banished from the Garden of Eden for yielding to their curiosity and eating a forbidden fruit. The book of Ecclesiastes specifically warns that “In much wisdom there is much grief, and increasing knowledge results in increasing pain.” The French abbot St. Bernard Clairvaux even pronounced in the twelfth century that curiosity is close to being a deadly sin: “To learn in order to know is scandalous curiosity.”

Galileo Galilei encountered the discouragement of curiosity in his interaction with the Catholic Church. When he tried to convince Pope Urban VIII that the heliocentric model, in which the Earth and all the other planets revolved around the Sun, was a correct representation of reality, the Pope retorted that irrespective of which model of planetary motion scientists were to adopt, “we cannot limit the divine power and wisdom to this way.” In other words, the Pope’s view was that the curiosity that drove Galileo to carry out his scientific research was to no avail since humans would never be able to decipher the cosmos. Queen Victoria had similar views. In a letter she wrote to her granddaughter Princess Victoria of Hesse, she advised: “I would earnestly warn you against trying to find out the reason for and explanation of everything ... To try and find out the reason for everything is very dangerous and leads to nothing but disappointment and dissatisfaction, unsettling your mind and in the end making you miserable.”

Unfortunately, attempts to suppress curiosity did not end centuries ago.

In 1937, the Nazi regime organized in Munich an exhibition which they entitled Degenerate Art, whose sole aim was to convince the public that modern art was simply a malicious attack by Jewish communists on the German people. The exhibit included works by a few of the greatest artists if the twentieth century, but the exhibition catalog described the art as having been produced by “sick brains.” Similarly appalling acts against curiosity have been carried out by the Taliban, culminating with the shooting of Malala Yousafzai in the head, because this young activist advocated education for girls.

Numerous incidents of book burning have also occurred throughout history, dating all the way back to the seventh century BCE, but continuing even to 1981, when the Jaffna Public Library of Sri Lanka was burned down by Sinhalese police and government-sponsored paramilitaries.

What is the lesson from all of these stories of oppression, intimidation, and assaults on curiosity? While writing my book WHY?, I coined the phrase: Curiosity is the best remedy for fear. What I mean by that is that often we are afraid of the unknown, of those things we know very little about. Becoming curious about them, and making an effort to learn more, usually acts to relieve that fear. The ability to be curious about almost anything you like (as long as you follow certain ethical guidelines related to privacy and to research involving human subjects) is, after all, a clear manifestation of freedom.

Since curiosity in humans is not only inevitable but is also a principal driver of the desire for the acquisition of knowledge, we should all be happy that the idiom “curiosity killed the cat” has a positive rejoinder: “But satisfaction brought it back!”


Livio, M. (2017). WHY?: What Makes Us Curious. New York: Simon and Schuster.

Livio, M. (2020). Galileo and the Science Deniers. New York: Simon and Schuster.