Round and brash, with the gravelly voice of a street fighter, Arthur Caplan looks and sounds more like a boxer than an ethi­cal philosopher. The director of the Center for Bioethics at the University of Pennsylvania, Caplan has been enormously influential in a variety of debates in modern biomedicine, from the fate of Terri Schiavo to the market for organs for transplant. He has written or coauthored more than 400 peer-reviewed articles and several books on the ethics of new medical technologies.

TR: Why should we care about bioethicists? Are they really so influential?

Caplan: Bioethics is most influential at the bedside. But the influence of bioethicists on research and human experimentation is also strong. Finally, conservative bioethicists have a lot of influence in Washington these days.

TR: How much of this activity is just window dressing? Arguably, it allows interested parties to say, “Look, we’ve got bioethicists here! We must be taking care of the ethics!”

Caplan: Well, that happens, but it doesn’t mean bioethicists don’t make a difference. Bioethics has real influence on legislation and regulation.

TR: What debates have you most influenced?

Caplan: I was involved in the National Organ Transplant Act. I single-­handedly held up the movement toward creating markets in organs. In genetics, I was the first guy on embryonic-stem-cell research. I was able to undermine the administration’s argument that the president’s position [which allowed federal funding of stem-cell research with cell lines that were already established] was a compromise. Since then, I’ve worked with patients’ groups and scientists to find a moral framework for embryonic-stem-cell research.

TR: You have not mentioned the death of Terri Schiavo. But last year it seemed you talked of little else: you were ceaselessly quoted in the media.

Caplan: I was the most outspoken critic of government intervention, that’s true. And I felt bullied by the president and by some members of Congress. But although we were outnumbered and outspent, it’s fair to say that we won that fight. Most Americans don’t want government intervention in end-of-life cases.

TR: Why should anyone listen to bioethicists?

Caplan: Critics sometimes say, “Well, who elected you king?” I smile and say, “If you don’t like what I say, just ignore it.” Look, bioethicists became influential for a reason: they were able to bridge the gaps between politicians, the media, and the sciences. But they’re not a priesthood, and they don’t have any authority to dictate anything to anybody.

TR: Do bioethicists say no a lot?

Caplan: We jokingly say that anyone can be a bioethicist: just say no to everything.

TR: You are held up as an expert on everything from assisted suicide to designer babies. You give great one-liners. But your ability can at times seem facile. Does this bother you?

Caplan: No–because it’s a skill I have, and I’m a quick study, and I can track a lot of stuff.

TR: Do some bioethics for us.

Caplan: There are people who have argued that tamoxifen [which may be an effective treatment for breast cancer] has too many side effects, such as ovarian cancer and eye problems. They think it might be unethical to use it as a prophylactic. I don’t agree. I think prevention is in some ways better than treatment. I’m not saying we should take every crazy risk, but I argued in favor of tamoxifen’s clinical trials.

TR: What are the principles that inform your opinions?

Caplan: I’m a consequentialist: I’m looking at outcomes. I’m trying to decide if a particular policy–such as allowing surgeons to do face transplants–would do more harm than good.

TR: That’s not much of an answer. What else would you do? Do consequentialists work from first principles?

Caplan: They can and do. Peter Singer [a Princeton University philosopher known for his view that acts should be judged according to whether they promote the preferences of feeling creatures, regardless of species] has his consequentialist utilitarianism, and he rigorously applies it. He says that if animals are smarter than retarded children, then experiment on retarded children. I’m not willing to trust any theory that far. In general, I’m not looking for fundamental truths when I discuss ethics. What matters is what is most practical at a given time. I ask, “What are the bene­fits and costs?” And I understand that the answer will change over time.

TR: Scientists often look down on bioethicists. Why?

Caplan: In the culture of science, the only thing that counts is the science. If you’re not doing that, it means you’re not smart or good enough.

TR: Do you ever wish you had become a scientist?

Caplan: I did go to medical school for a while, at Columbia. I liked it, but I don’t have the patience for the level of detail that makes good science.

Disclaimer: Arthur Caplan is on the board of advisors of BioAgenda, the nonprofit institute of which David Duncan is the editorial director.