Cryonics Proponent Thomas
Cryonics (often mistakenly called "cryogenics") is the practice of cryopreserving humans or animals that can no longer be sustained by contemporary medicine until resuscitation may be possible in the future.
The process is not currently reversible. Cryonics can only be performed on humans after clinical death, and a legal determination that further medical care is not appropriate (legal death). The rationale for cryonics is that the process may be reversible in the future if performed soon enough, and that cryopreserved people may not really be dead by standards of future medicine.
The central premise of cryonics is that memory, personality, and identity are stored in the structure and chemistry of the brain. While this view is widely accepted in medicine, and brain activity is known to stop and later resume under certain conditions, it is not generally accepted that current methods preserve the brain well enough to permit revival in the future. Cryonics advocates point to studies showing that high concentrations of cryoprotectant circulated through the brain before cooling can largely prevent freezing injury, preserving the fine cell structures of the brain in which memory and identity presumably reside.
Currently cells, tissues, blood vessels, and some small animal organs can be reversibly cryopreserved. Some frogs can survive for a few months in a partially frozen state a few degrees below freezing, but this is not true cryopreservation. Cryonics advocates counter that demonstrably reversible preservation is not necessary to achieve the present-day goal of cryonics, which is preservation of basic brain information that encodes memory and personal identity. Preservation of this information is said to be sufficient to prevent information theoretic death until future repairs might be possible.
Damage from ice formation and ischemia
The freezing process creates ice crystals, which some scientists have claimed damage cells and cellular structures so as to
The process is not currently reversible. Cryonics can only be performed on humans after clinical death, and a legal determination that further medical care is not appropriate (legal death). The rationale for cryonics is that the process may be reversible in the future if performed soon enough, and that cryopreserved people may not really be dead by standards of future medicine.
The central premise of cryonics is that memory, personality, and identity are stored in the structure and chemistry of the brain. While this view is widely accepted in medicine, and brain activity is known to stop and later resume under certain conditions, it is not generally accepted that current methods preserve the brain well enough to permit revival in the future. Cryonics advocates point to studies showing that high concentrations of cryoprotectant circulated through the brain before cooling can largely prevent freezing injury, preserving the fine cell structures of the brain in which memory and identity presumably reside.
Currently cells, tissues, blood vessels, and some small animal organs can be reversibly cryopreserved. Some frogs can survive for a few months in a partially frozen state a few degrees below freezing, but this is not true cryopreservation. Cryonics advocates counter that demonstrably reversible preservation is not necessary to achieve the present-day goal of cryonics, which is preservation of basic brain information that encodes memory and personal identity. Preservation of this information is said to be sufficient to prevent information theoretic death until future repairs might be possible.
Damage from ice formation and ischemia
The freezing process creates ice crystals, which some scientists have claimed damage cells and cellular structures so as to