We haven&#x27;t proven it <i>cannot</i> work. But we don&#x27;t know if we&#x27;re doing it right. We don&#x27;t know if just the head is enough, or if including the whole body slows the process so much the brain is damaged. We don&#x27;t know if we&#x27;re using chemicals that best accommodate thawing or scanning, whichever turns out to work better. We don&#x27;t know if waiting until death causes some kind of irreversible damage or psychological problems.