Medical ethicist Art Caplan joined Boston Public Radio for his weekly "Ask the Ethicist" segment. Caplan talked about primary care doctor shortages, solitary confinement for Dzhokhar Tsarnaev, medically-dubious "head transplants," and Warren Buffett's advocacy for Coke and fried potato products.

Questions below have been rephrased. Caplan's responses have been edited where indicated [...].

A new study predicts a significant primary care doctor shortage by 2025. Why is that?

The specialties are very attractive. [Doctors say,] 'Boy, I could get triple the amount of money if I'm going into a specialty instead of a primary care thing.' [...] But we've got telemedicine. We can shoot images around, and you can see — in places like Alaska — where they've been doing that for a while.

Will we see more offices using telemedicine to treat patients?

I think a lot more of us are going to be talking on the computer, because that's also a better way to harangue [patients] in between doctor visits. [...] Some of this is sending information, [...] radiology, your head exam, it doesn't matter where that's looked at, as long as it's looked at by someone competent.

There are clearly areas where telemedicine has its limitations.

I don't think it's a solution to mental health [treatment].

Dzhokhar Tsarnaev has been held in solitary confinement for 23 hours a day since he was arrested. Do you think solitary is appropriate in some cases?

[The] Eastern State Penitentiary in Philadelphia [...] set up a prison where everybody was in solitary, and they had a Bible, and that was it. [...] What we saw way back then is that people went crazy. [...] If you want them in a sense to appreciate their punishment, you can't drive them insane. [...] I think constant solitary is probably inhumane. You're going to lose your mind.

Dr. Sergio Canavero recently announced his intention to transplant the heads of people suffering from life-ending ailments onto new bodies, a so-called "head transplant." Dr. Canavero said it would be feasible within two years.

He says we're ready to go. [...] Look, [in a face transplant] you're going to pour all this immuno-suppression into people which can prevent infection. [...] The head transplant is the same thing, but worse.

So, not possible.

Moving a head, with all that tissue and a lot of skin? I don't think that would work. [...] If we knew how to regenerate the spinal cord, which is key, there wouldn't be so many people [paralyzed].

Warren Buffett recently revealed to Fortune magazine that he "stays young" by drinking five Cokes a day and eating Utz Potato Stix. Is it irresponsible for a person of his stature to be doling out medical advice?

I bet he has good medical care. [...] I had a teacher when I was getting my philosophy degree who smoked three packs of Camels a day. [...] There are people that just have the best genes on Earth, and they can overwhelm these things! [...] They beat the odds, but the fact is, there are odds. [...] You want to try to beat the odds, or do you want to lower the odds?