Then there’s the cost. Alcor charges $80,000 to store a person’s brain, and around $220,000 to store a whole body. Tomorrow.Bio’s charges are slightly higher. Many people, including Kendziorra himself, opt to cover this cost via a life insurance policy.

Perhaps the main reason people don’t opt for cryonic preservation is that we don’t have any way to bring people back. Bedford has been in storage for more than 50 years, Coles for more than a decade. All the scientists I’ve spoken to say the likelihood of reanimating remains like theirs is vanishingly small.

The fact that the possibility—however tiny—is above zero is enough for some, including Nick Llewellyn, the director of research and development at Alcor. As a scientist, he says, he acknowledges that the chances reanimation will actually work are “pretty low.” Still, he’s interested in seeing what the future will look like, so he has signed himself up for the cryonic preservation of his brain.

But Shannon Tessier, a cryobiologist at Massachusetts General Hospital, tells me that she wouldn’t sign up for cryonic preservation even if it worked. “It turns into a philosophical question,” she says.

“Do I want to be revived hundreds of years later when my family is gone and life is different?” she asks. “There are so many complicated philosophical, societal, [and] legal complications that need to be thought through.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.