41 Essays on Infinite Lifespans   Aubrey de Grey generation of sesquicentenarians will mostly not die involun- tarily; their acquisition (by the means described in previous sections) of a 5000-year life expectancy means that, even if the scanning and reconstruction technology posited in this section takes 500 years to develop, most of them will still be alive – in a youthful state – to take advantage of it. I now return to the topic of resuscitating cryonics patients. Much work has gone into developing technology to lower a person to liquid nitrogen temperatures without forming ice crystals in their cells, because such crystals decimate cell mem- branes and thereby render implausible the resuscitation of the individual in the future, even presuming sophisticated tech- nology to address the cause of their death. [22] I think this may not have been as important as most have supposed, and I base this view on a consideration of the circumstances in which a cryonics patient is and is not likely to be devitrified. It will not be enough to have cryopreserved and resuscitated a chimpanzee, for example, and failed to detect any differ- ence in its personality, because assays of that personality will be inadequate to reveal changes of a subtlety that would still matter if they occurred in a human. The choice to resuscitate will simply not be made while even a small risk is perceived that  a  resuscitation  will  be  only  a  qualified  success,  and  if technology can be foreseen (even distantly so) which would substantially diminish that risk. Hence, I strongly suspect that those currently residing in cryonic containers in Scottsdale and Detroit will be resuscitated by the scanning and recon- struction  approach  just  outlined,  and  not  by  thawing  or devitrifying  their  original  body.  And  it  seems  highly  likely that such a scan could be performed just as successfully on a brain shot through with ice crystals as on one that had been perfectly vitrified.