Information theoretical death
Encyclopedia
Information-theoretic death is the destruction of the information within a human brain (or any cognitive structure capable of constituting a person) to such an extent that recovery of the original person is theoretically impossible by any physical means. The concept of information-theoretic death arose in the 1990s in response to the problem that as medical technology advances, conditions previously considered to be death, such as cardiac arrest
, become reversible and are no longer considered to be death.
"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death
and legal death
, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology
raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory
.
The paper Molecular Repair of the Brain by Ralph Merkle
defined information-theoretic death as follows:
The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after many hours of clinical death
at room temperature as the brain undergoes autolysis
. It can also occur more rapidly if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death
, or during the progression of degenerative brain diseases that cause extensive loss of brain structure. Exactly when complete and total information-theoretic death might occur with respect to different types of preservation and decomposition might also be relevant to the speculative field of mind uploading.
"Information-theoretic death" also arises in the context of cryonics
, which can be viewed as the use of cryopreservation
to attempt to prevent information-theoretic death. The use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead. In contrast, if cryonics cannot be applied before information-theoretic death occurs, or if the cryopreservation procedure itself causes information-theoretic death, then cryonics is not feasible.
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
, become reversible and are no longer considered to be death.
"Information-theoretic death" is intended to mean death that is absolutely irreversible by any technology, as distinct from clinical death
Clinical death
Clinical death is the medical term for cessation of blood circulation and breathing, the two necessary criteria to sustain life. It occurs when the heart stops beating in a regular rhythm, a condition called cardiac arrest. The term is also sometimes used in resuscitation research.Stopped blood...
and legal death
Legal death
Legal death is a legal pronouncement by a qualified person that further medical care is not appropriate and that a patient should be considered dead under the law. The specific criteria used to pronounce legal death are variable and often depend on certain circumstances in order to pronounce a...
, which denote limitations to contextually-available medical care rather than the true theoretical limits of survival. In particular, the prospect of brain repair using molecular nanotechnology
Molecular nanotechnology
Molecular nanotechnology is a technology based on the ability to build structures to complex, atomic specifications by means of mechanosynthesis. This is distinct from nanoscale materials...
raises the possibility that medicine might someday be able to resuscitate patients even hours after the heart stops. The term "information-theoretic" is used in the sense of information theory
Information theory
Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. Information theory was developed by Claude E. Shannon to find fundamental limits on signal processing operations such as compressing data and on reliably storing and...
.
The paper Molecular Repair of the Brain by Ralph Merkle
Ralph Merkle
Ralph C. Merkle is a researcher in public key cryptography, and more recently a researcher and speaker on molecular nanotechnology and cryonics...
defined information-theoretic death as follows:
A person is dead according to the information-theoretic criterion if their memories, personality, hopes, dreams, etc. have been destroyed in the information-theoretic sense. That is, if the structures in the brain that encode memory and personality have been so disrupted that it is no longer possible in principle to restore them to an appropriate functional state, then the person is dead. If the structures that encode memory and personality are sufficiently intact that inference of the memory and personality are feasible in principle, and therefore restoration to an appropriate functional state is likewise feasible in principle, then the person is not dead.
The exact timing of information-theoretic death is currently unknown. It has been speculated to occur gradually after many hours of clinical death
Clinical death
Clinical death is the medical term for cessation of blood circulation and breathing, the two necessary criteria to sustain life. It occurs when the heart stops beating in a regular rhythm, a condition called cardiac arrest. The term is also sometimes used in resuscitation research.Stopped blood...
at room temperature as the brain undergoes autolysis
Autolysis (biology)
In biology, autolysis, more commonly known as self-digestion, refers to the destruction of a cell through the action of its own enzymes. It may also refer to the digestion of an enzyme by another molecule of the same enzyme....
. It can also occur more rapidly if there is no blood flow to the brain during life support, leading to the decomposition stage of brain death
Brain death
Brain death is the irreversible end of all brain activity due to total necrosis of the cerebral neurons following loss of brain oxygenation. It should not be confused with a persistent vegetative state...
, or during the progression of degenerative brain diseases that cause extensive loss of brain structure. Exactly when complete and total information-theoretic death might occur with respect to different types of preservation and decomposition might also be relevant to the speculative field of mind uploading.
"Information-theoretic death" also arises in the context of cryonics
Cryonics
Cryonics is the low-temperature preservation of humans and animals who can no longer be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Cryopreservation of people or large animals is not reversible with current technology...
, which can be viewed as the use of cryopreservation
Cryopreservation
Cryopreservation is a process where cells or whole tissues are preserved by cooling to low sub-zero temperatures, such as 77 K or −196 °C . At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped...
to attempt to prevent information-theoretic death. The use of information-theoretic criteria has formed the basis of ethical arguments that state that cryonics is an attempt to save lives rather than being an interment method for the dead. In contrast, if cryonics cannot be applied before information-theoretic death occurs, or if the cryopreservation procedure itself causes information-theoretic death, then cryonics is not feasible.