Column: To a lab mouse

Physics research as a whole doesn’t involve animals very often, but studies in biophysics and medical physics often do, and occasionally we cover them. I recently wrote an online piece (which I’ll be expanding into a longer story for the March issue) about some experiments involving mice, and I was reminded of one of my first stories , from 2008, about an experiment on the mechanics of turkeys’ leg muscles.

In writing the story, I felt it was important to mention that the turkeys involved were all killed at the end. My rationale, I remember, was that it was similar to mentioning the monetary cost of a giant facility like the Large Hadron Collider: Give readers an unvarnished account of what it took to perform an experiment, and let them make up their own minds about whether the knowledge gained was worth it.

My colleagues’ reactions to the inclusion were mixed. One remarked that it was a “downer.” Others thought it was irrelevant. Still others worried that we’d be inundated with outraged letters from “PETA people.” In the end, Charles Day (who’s now Physics Today‘s editor-in-chief, and who at the time was the senior editor in charge of the Search & Discovery department) agreed that it was appropriate, and the sentence made it into print.

Miller’s Diary

Physics Today editor Johanna Miller reflects on the latest Search & Discovery section of the magazine, the editorial process, and life in general.

We never got the predicted letters. Maybe not many PETA people read Physics Today.

The ethics of human life and death is a thorny enough topic, and philosophers have devised plenty of thought experiments to challenge (or trick, confuse, or annoy, depending on your point of view) one’s moral intuition. With animals in the mix, two new questions arise: How do animals differ cognitively from humans? And what’s the moral relevance of those differences?

In his poem To a Mouse , Robert Burns reflects a bit on the first question. (Incidentally, when the poem sprang to mind as the inspiration for the title of this column, I hadn’t even realized that Burns was such an outspoken critic of cruelty to animals. I was familiar only with his greatest hits , so I was very interested to learn of his strong opinions on wounded hares and the hunters responsible for them.) After empathizing with the “wee, sleekit, cowrin, tim’rous beastie” and expressing regret over destroying her nest, he concludes that she’s “blest” because mice, unlike humans, can’t visualize the future clearly enough to worry about it. He does not, however, explain why he believes that to be the case.

Nearly two centuries later, in the landmark 1975 book Animal Liberation (without which, arguably , there would have been no PETA people), philosopher Peter Singer touches on a similar theme: Part of what makes killing wrong stems from the victim’s capacity to have desires for the future. Because that capacity is difficult to evaluate in animals, Singer sidesteps the issue. He has little to say about the ethics of killing animals, and he focuses instead on the more clear-cut wrongness of inflicting physical pain and suffering on them. He still finds plenty to fault in his contemporaries’ treatment of animals.

Singer takes a utilitarian approach to philosophy, which I largely agree with: The best course of action is the one that produces the greatest good for the greatest number, regardless of whether it aligns with any preconceived virtues, rights, or divine ordinances. His thesis in Animal Liberation is that animals’ interests should be included in that calculus. So, for example, to evaluate the rightness or wrongness of an experiment on mice that might lead to a new cancer treatment, one would weigh the harm done to the mice against the suffering potentially prevented in the people who would benefit from the treatment. Or, in the work that was the topic of my 2008 story, the beauty and potential applications of an interesting insight into muscle mechanics would be weighed against the lives of 10 turkeys.

But the parties affected by an action are rarely so easily circumscribed, and it’s nearly always possible to find more interests to add to either side of the balance. If you’re not careful, you might be tempted to keep adding terms to the equation until you get the answer you were hoping for. In the case of the cancer study, what about the people who don’t have cancer and never will, but who feel comforted to live in a world where progress is being made in medical research—do their interests, too, get considered against those of the mice?

In the years I’ve spent reporting on research across the physical sciences, one thing I’ve come to really admire about the researchers I write about is how diligent they are to avoid even inadvertently biasing their results. Complicated and subtle experiments—including both the ones I’m writing about for the March issue—often employ various forms of blind data analysis to shield the researchers from the temptation to tinker with their numbers until their desired outcome emerges.

I hope we can all aspire to the same level of intellectual honesty in thinking about ethics, in regard to animals and everything else. I can’t tell you what you should think about whether animal experimentation is right or wrong. But I can tell you that if you’re going to ask the question, you should be open to the possibility of an answer you don’t like.