White was convinced, though, that his work with cephalosomatic linkage surgery in the monkey was pretty much proof that it was "fully accomplishable in the human sphere." By 1999 he said it was "now possible to consider adapting the head-transplant technique to humans."

People called him a genius. Gave him honorary degrees. People also call(ed) him crazy.

Jump forward to 2013, when last month Italian surgeon Sergio Canavero said that we have at last figured out that issue of connecting the spinal cord. The head transplant is now feasible, said Canavero, and he has a project called HEAVEN that's going to do it.

HEAVEN stands for Head Anastomosis Venture, which is a poor choice of acronyms in an industry constantly sidestepping God-complex accusations. Maybe it's like, ironic in a super self-aware way. That would be unique among the pages of the journal Surgical Neurology International, though, where Canavero dives deep into the specifics of how HEAVEN will work. So deep that we arrive at the existential.

For example, is it a head transplant? Technically it would be a body transplant. Identity remains with the brain. Doesn't it? If the chimera were to have sex and bear a child, though, it would have the genetic identity of the parent's body, not its head.

In Thomas Mann's 1959 novel The Transposed Heads, which is based on a traditional Indian folk tale, the two male protagonists behead themselves, and their heads are magically reattached, but to the other's body. One man's wife, Sita, subsequently has difficulty knowing which to take as her husband: the head or the heart.

Canavero does convey only the most benevolent of intentions, writing of the potential to use head transplants in patients with "horrible conditions without a hint of hope of improvement [that] cannot be relegated to the dark corner of medicine." He mentions tetraplegic patients, those with multi-organ failure, or intractable cancer that involves much of the body but not the head. The first patient to undergo head transplantation, though, "should be someone, probably young, suffering from a condition leaving the brain and mind intact while devastating the body, for instance, but by no means exclusively, progressive muscular dystrophies or even several genetic and metabolic disorders of youth."

Silver remains a non-believer. Earlier this year his team successfully fixed the spinal cords of rats that had them completely severed. Others have done it for dogs and pigs. When Danielle Elliot at CBS asked Silver about Canavero's proclamation that all of this could be done in humans, though, he laughed. "It's light years away from what they're talking about." Silver's experiments involved a clean cut to the spinal cord, and nothing but the spinal cord, and not involving a second animal. He told CBS, "To sever a head and even contemplate the possibility of gluing axons back properly across the lesion to their neighbors is pure and utter fantasy in my opinion ... Just to do the experiments is unethical."