Scientific Justification of Cryonics Practice

Very low temperatures create conditions that can preserve tissue for centuries, possibly in-cluding the neurological basis of the human mind. Through a process called vitrification, brain tissue can be cooled to cryogenic temperatures without ice formation. Damage associ-ated with this process is theoretically reversible in the same sense that rejuvenation is theo-retically possible by specific foreseeable technology. Injury to the brain due to stopped blood flow is now known to result from a complex series of processes that take much longer to run to completion than the 6 min limit of ordinary resuscitation technology. Reperfusion beyond the 6 min limit primarily damages blood vessels rather than brain tissue. Apoptosis of neu-rons takes many hours. This creates a window of opportunity between legal death and irre-trievable loss of life for human and animal subjects for cryopreservation with possibility of future resuscitation. Under ideal conditions, the time interval between onset of clinical death and beginning of cryonics procedures can be reduced to less than 1 min, but much longer de-lays could also be compatible with ultimate survival. Although the evidence that cryonics may work is indirect, the application of indirect evidence is essential in many areas of sci-ence. If complex changes due to aging are reversible at some future date, then similarly com-plex changes due to stopped blood flow and cryopreservation may also be reversible, with life-saving results for anyone with medical needs that exceed current capabilities. 49