Judith Jarvis Thomson (1929-2020) is one of the most influential ethicists and metaphysicians of the 20th century. She’s known for changing the conversation around abortion, as well as modernising what we now know as the trolley problem.

Thomson was born in New York City on October 4th, 1929. Her mother was Catholic of Czech heritage and her father was Jewish,  who both met at a socialist summer camp. While her parents were religious, they didn’t impose their beliefs on her.  

At the age of 14, Thomson converted to Judaism, after her mother died and her father remarried a Jewish woman two years later. As an adult, she wasn’t particularly religious but she did describe herself publicly as “feel[ing] concern for Israel and for the future of the Jewish people.”   

In 1950, Thomson graduated from Barnard College with a Bachelor of Arts (BA), majoring in philosophy, and then received a second BA in philosophy from Cambridge University in England in 1952. She then went on to receive her Masters in philosophy from Cambridge in 1956 and her PhD in philosophy from Columbia University in New York in 1959.   

Violinists, trolleys and philosophical work

Even though she had received her PhD from Columbia, the philosophy department wouldn’t keep her as a professor as they didn’t hire women. In 1962, she began working as an assistant professor at Barnard college, though she later moved to Boston University and then MIT with her husband, James Thomson, for the majority of her career.  

Thomson is most famous for her thought experiments, especially the violinist case and the trolley problem. In 1971, Thomson published her book A Defense of Abortion, which presented a new kind of argument for why abortions are permissible during a time of heightened debate in the US as a result of the second wave feminist movement. Arguments that defended a woman’s right to an abortion circulated feminist publications and eventually led to the Supreme Court ruling in favour of Roe v. Wade (1973) 

“Opponents of abortion commonly spend most of their time establishing that the foetus is a person, and hardly any time explaining the step from there to the impermissibility of abortion.” – Judith Jarvis Thomson

The famous violinist case asks us to imagine if it is permissible to “unplug” ourselves from a famous violinist, even if it is only for nine months and being plugged in is the only thing keeping them alive. As Thomas Nagel said, she expresses very clearly the essentially negative character of the right to life, which is that it’s a right not to be killed unjustly, and not a right to be provided with everything necessary for life.” To this day, the violinist case is taught in classrooms and recognised as one of the most influential thought experiments arguing for the permissibility of abortion.  

Thomson is famous for another famous thought experiment, the trolley problem. In her 1976 paper “Killing, Letting Die and the Trolley Problem,” Judith Jarvis Thomson articulates a famous thought experiment, first imagined by Philippa Foot, that encourages us to think about the moral relevance of killing people, as opposed to letting people die by doing nothing to save them.  

In the trolley problem thought experiment, a runaway trolley will kill five innocent people unless someone pulls a lever. If the lever is pulled, the trolley will divert onto a different track and only one person will die. As an extension to Foot’s argument, Thomson asks us to think if there is something different about pushing a large man off a bridge, thereby killing him, to prevent five people from dying from the runaway trolley. Why does it feel different to pull a lever rather than push a person? Both have the same potential outcomes and distinguish between killing a person and letting a person die.

In the end, what Thomson finds is that oftentimes, the action as well as the outcome are morally relevant in our decision making process.  


Thomson’s extensive philosophical career hasn’t gone unnoticed. In 2012, she was awarded the American Philosophical Association’s prestigious Quinn Prize for her “service to philosophy and philosophers.” In 2015, she was awarded an honorary doctorate by the University of Cambridge, and then in 2016 she was awarded another honorary doctorate from Harvard.   

Thomson continues to inspire women in philosophy. As one of her colleagues, Sally Haslanger, says: “she entered the field when only a tiny number of women even considered pursuing a career in philosophy and proved beyond doubt that a woman could meet the highest standards of philosophical excellence … She is the atomic ice-breaker for women in philosophy.”