The legacy of philosopher Judith Jarvis Thomson: Moral pioneer who wrote 'A Defense of Abortion' dies at 91

Just as the landmark abortion case Roe v. Wade was headed before the United States Supreme Court, a new journal of academic philosophy prepared to publish its inaugural issue including an innovative argument from Judith Jarvis Thomson. That 1971 paper, "A Defense of Abortion," published in Philosophy & Public Affairs, became one of the most influential pieces of contemporary applied ethics, an enduring part of the legacy left behind when she died at 91 on Nov. 20, 2020.

"It has had such an incredible impact on people who have taken philosophy classes," Sally Haslanger, a professor of philosophy and women's and gender studies at MIT, where she worked alongside Professor Thomson, told me. "Almost anybody who teaches contemporary moral problems or an intro to moral philosophy is likely to teach that paper."

The key genius of the paper, one of the sources of its originality and staying power, is that it conceded to the opponents of abortion their strongest premise: that a fetus is a person worthy of full moral concern. Thomson didn't defend this view — in fact, she had serious objections to it — but she wanted to show that even if we believe a fetus has as much a right to live as anyone else, it doesn't follow that abortion is impermissible.

To make her case, Thomson spun an elaborate and memorable thought experiment:

You wake up in the morning and find yourself back to back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist's circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you, "Look, we're sorry the Society of Music Lovers did this to you—we would never have permitted it if we had known. But still, they did it, and the violinist is now plugged into you. To unplug you would be to kill him. But never mind, it's only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you."

"I imagine you would regard this as outrageous," she told her readers, counting on the widely shared view that the kidnapped person would not be obligated to give over their body in this way.

The paper goes on to argue that this case, along with increasingly fanciful examples that illuminate different features of pregnancy and address potential counterarguments, shows something perhaps unexpected about our moral intuitions: A right to life is not always the end of an ethical argument. We are not morally required to forfeit control over our bodies, even if death of another may be the foreseeable result. Abortion, therefore, may be permissible, even if pro-life arguments about the moral status of the fetus are correct.

It was an impressive argument, and it resonates today in the feminist rallying cry "My body, my choice."

"It's had a huge influence in the field. No argument about abortion can proceed without taking her arguments really seriously, even if it ends up opposing abortion," Kate Manne, a philosophy professor at Cornell University who worked with Thomson while studying at MIT, told me.

Despite its remarkable impact, though, Manne argued the central thesis of "A Defense of Abortion" is still underappreciated.

"I actually think it should have had more influence than it did," she said. "We're still at this annoying dialectical point where the personhood of the fetus is taken establish the impermissibility of abortion in wider culture. So it's still a very good thing that Judy's piece showed that that's far too quick. But in a way, I wish it had had more uptake."

Thomson's paper isn't just notable for its influence or the importance of its ideas about morality. As a piece of philosophy, it's exceptionally inventive and lucid. It's also particularly memorable. The structure of the thought experiment she used didn't need the patient with a kidney ailment be a violinist, as opposed to an unidentified person, but these kinds of details add color and life to what could otherwise be a stark examples. Her personal humor and charm were reflected in her writing.

"She's quite witty about it," Manne said of Thomson's argumentation style. "She says if she needed Henry Fonda's cooling touch upon her fevered brow, it would be 'frightfully nice for him to fly in from the West Coast to apply it' and save her life. But she isn't owed that by him."

Of course, excessively creative thought experiments in an argument have the potential to bog a paper down or complicate an argument unnecessarily, if not deployed right. But Thomson was a master of the form, using a series of whimsical examples to convince the reader of the plausibility of her view while never abandoning or distracting from the rigor of her argument.

But while it's undoubtedly her best-known contribution to philosophy, the paper on abortion didn't define her career. Within academia, Thomson wasn't known solely as a philosopher of applied ethics. Much of her work focused on foundational issues in philosophy and metaphysics, such as the nature of normativity, moral objectivity, composition, and action.

In its own way, Thomson's presence in these debates was perhaps as bold and unflinching as her views on abortion.

"Philosophy is male-dominated, but metaphysics is the most-male dominated, even now," Haslanger explained. "I came up in a period in grad school in the '80s, mainly. Judy was already producing really stunning work. And I started my career in analytic metaphysics. This remains a field where there are not very many women. And I would look in the bibliographies of the books I was encouraged to read or the articles I was encouraged to read, just looking for any name of a woman. And there were always only two, pretty much: Ruth Barcan Marcus and Judith Jarvis Thomson."

Thomson made significant contributions, for example, to debates about the concept of goodness, which she leveraged to make nuanced arguments against one of the most dominant theories in philosophical ethics.

In Thomson's view, good "isn't the kind of thing appropriately applied to states of affairs," said Haslanger. Something can't merely be good, simpliciter. It has to be good in some way. "So you can have a good toaster, or a good breakfast, or a good person. But a good state of affairs — states of affairs don't have criteria of goodness built into them."

This conclusion, she argued, was a big problem for utilitarianism and other consequentialist theories, which hold, more or less, that actions are to be judged by the consequences or states of affairs that they bring about. For Thomson, this view wasn't even really coherent, Haslanger said.

But she could be surprisingly effusive about views she didn't hold. Once, in a talk of hers I heard addressing another objection to utilitarianism, Thomson began by emphasizing the strengths of the view, arguing that there were many things about the theory to recommend it. "Many things," she stressed, repeating herself for emphasis.

First and foremost, the best reason to be impressed with utilitarianism was the simplest: "It's a theory!" she exclaimed.

Thomson made clear that many of the alternatives to utilitarianism that have been proposed over the years wouldn't merit this designation. And for her, utilitarianism's status as a full-fledged theory was undoubtedly high praise.

Her firm opposition to utilitarianism, though, was manifest in another of her philosophical contributions that has reached far beyond the academy and into the popular imagination: Trolley problems.

She actually credited the invention of the problem type to philosopher Philippa Foot, but it was Thomson who clarified and popularized the topic, which has become a sub-field of ethics in its own right known as trolleyology. In her first paper laying out the problem, she put forward the now-standard formulation:

Suppose you are the driver of a trolley. The trolley rounds a bend, and there come into view ahead five track workmen, who have been repairing the track. The track goes through a bit of a valley at that point, and the sides are steep, so you must stop the trolley if you are to avoid running the five men down. You step on the brakes, but alas they don't work. Now you suddenly see a spur of track leading off to the right. You can turn the trolley onto it, and thus save the five men on the straight track ahead. Unfortunately, Mrs. Foot has arranged that there is one track workman on that spur of track. He can no more get off the track in time than the five can, so you will kill him if you turn the trolley onto him. Is it morally permissible for you to turn the trolley?

Almost everyone seems to agree that it's permissible to turn the trolley, she explained. More debate breaks out when you ask whether you are morally required to turn the trolley. But the structure of the case lends itself to endless variation: What if you're not the driver, but just a bystander able to pull a lever and divert the trolley? What if the trolley loops around, such that the crushing of the one person isn't just an alternative to the deaths of the five, but would actually slow the trolley and thus be the means by which the others are saved? And why does this case strike us so differently than a case of a surgeon who kills one unsuspecting healthy person to harvest organs that will save the lives of five patients who would otherwise die?

On an austere consequentialist or utilitarian approach to moral reasoning, all these problems have simple answers: make the choice that results in the most lives saved, that does the most good. But Thomson reveled in complexities and qualifications of our moral commitments, and she rejected simplistic solutions. This wasn't mere pedantry for its own sake — she was deeply concerned with the principles that underlie our intuitions in these cases and what they can tell us about morality.

Her work on the topic eventually led her to change her mind about a key part of the problem, which she explained once in a seminar at MIT in 2013 that I was lucky enough to attend. She argued that a bystander watching the trolley would not be permitted, despite what she had previously believed and argued, to pull a switch to save the five people and kill the one.

How did she reach this startling conclusion? She imagined a new scenario in which the bystander had the opportunity to flip the switch to direct the trolley away from the five people and toward herself. Were she so noble, she might be willing to make that choice. But in Thomson's view, she wasn't obligated to make this choice. In an argumentative move that echoes the insight from "A Defense of Abortion," she posited that morality doesn't require us to sacrifice our lives for the lives of five others.

But if that's the case, she reasoned, then how can the bystander in the original case make the decision for the one person on the track to sacrifice her life for the other five? The bystander can't justify that choice, in Thomson's view. Despite what most people's intuition tells them, it's not permissible to flip the switch to kill one and save five from the oncoming trolley.

Her views weren't unforgiving or completely absolutist, though. If the cost were high enough, you might be obligated to flip the switch. Were the trolley carrying a bomb and on a course to destroy New York City, you ought to kill the one person to save the lives of millions.

"We must save New York!" she said.

One characteristic about Thomson that came through both in her writing and when she spoke was a firm belief that when discussing these kinds of ethical questions, there is a correct answer, even if it's hard to discern. In one seminar I attended at MIT, the group discussed whether the concept of "ought" is objective or subjective. Does it make sense to think of what we "ought" to do in a moral dilemma as reflecting the objective conditions, or our subjective perception of those conditions?

Debating this question, naturally, brings up more clever thought experiments, some of which seem to suggest that "ought" must be interpreted objectively, while others suggest a subjective interpretation of "ought" is best. It seemed to me that the solution is to simply stipulate that sometimes "ought" is used in a subjective sense, and sometimes it is used in an objective sense.

Thomson disagreed. She believed "ought" is objective — end of story. The clever counterexamples that suggest otherwise were certainly worth considering for her, but they weren't a reason to back down from the idea that there was a definitive answer to the puzzle.

This conviction stood out, especially because it was matched by fierce wit.

"There was just no one like her," said Haslanger. "To have a woman being really right in the thick of it, out-arguing others and making her way. It was really inspiring to me."

Thomson's confidence, fortitude and toughness were undoubtedly necessary for the career she had. Without this disposition, she may not have lasted in the world of academic philosophy or had such an impact at the time she entered the field.

"I found it in the eighties and nineties just awful to try to survive in mainstream analytic metaphysics," Haslanger explained. "It was just grueling. And that Judy did that a whole generation ahead of me is just mind-boggling. And she would comment on that now and then. She wasn't someone to complain or make a fuss about things that happened to her along the way. But you can't survive it unless you're very strong-minded and very determined, and brilliant. And she was all those things."

But if that toughness helped her survive, she didn't feel a need to abandon it once she had reached the pinnacle of her career. She was known as a fierce critic of students' papers. Getting the mechanics of a philosophical paper right — not just the argument, but the structure and the presentation of the ideas, down to the level of the sentence — was a top priority for her.

Manne remembered how Thomson subjected her work as a grad student to exacting standards. Those lessons stayed with Manne and influence her writing to this day, though she doubted that Thomson would always be satisfied with the results.

"She brought me into her office," Manne recounted, "having read a paper of mine, and very plainly said, in a tone that was genuinely warm: 'This paper is terrible!'"

Manne added: "She was incredibly tough, but I always got the sense that she was tough in the service of making people better philosophers. She was never just mean."

For Haslanger, this side of Thomson was an asset. Haslanger joined the philosophy department faculty at MIT when Thomson was the only other woman.

"I'm known for my strong feminist, anti-racist views, and I express them often and loudly. And I came to MIT, and it was the first time in my career where I could be the feminist 'good cop,' because Judy had spent so many years already being the feminist 'bad cop.' So we kind of worked together quite well. And it was such a relief," said Haslanger. "We definitely worked well together on encouraging people, and insisting, in fact, that people take women seriously."

She added: "She really was a symbol, an icon for many of us, who gave us hope and gave us courage to carry on."

It's notable, though, that — with the one clear exception — Thomson's work itself wasn't feminist philosophy. She generally worked on the traditional types of ethical and metaphysical questions handed down in the canon of philosophy, a canon that was historically fashioned by men. Questions that male philosophers have tended to ignore, such as those about the nature of gender oppression, say, didn't draw Thomson's scrutiny in the way traditional questions about the relationship between the statue and the clay or personal identity over time did.

The exception, of course, is her defense of abortion — what she's best known for.

"The fact that she just did what she did was a powerful feminist intervention. Her being who she was was a feminist intervention. I don't think that her work draws on gendered experience, or shows herself to draw on her feminist commitments to intervene in a debate, except for the abortion paper," said Haslanger.

"Whether or not she would have avowed it, I do think there's something feminist about her tough and unapologetic stance on bodily autonomy being something that is important, and that people have a right to, within limits," said Manne. "It really is about ways in which we've perhaps been myopic about the fact that women are entitled to bodily control, even if others depend upon them for their lives, which really is a deeply feminist point."