"If your stack is destroyed, you die. There's no coming back from real death".
Origin and Function
Cortical Stacks serve as a receptacle for the human consciousness or Digital Human Freight (D.H.F.). All citizens within the Protectorate have a cortical stack implanted when they are one year old.
Cortical Stacks are composed of a non terrestrial metal left by an Alien Civilization along with astrogation charts mapping several habitable planets within the galaxy. Cortical Stacks were originally developed as a means of interstellar travel to reach these planets. By downloading the human consciousness they were able to transmit it to a waiting body or "Sleeve" on a distant planet. This method of transmitting consciousness off-world, called Needlecasting, allowed instant travel to anywhere in the Settled Worlds that otherwise would take centuries to reach by traditonal means.
Over time this technology would become a method of immortality for those who could afford it. Placing the dead in new bodies, called "Re-sleeving", can be accomplished by simply downloading consciousness in a new Sleeve after death as long as the Cortical Stack is intact after sleeve-death. Citizens who cannot afford re-sleeving or do not want to be re-sleeved have their Cortical Stacks placed in a storage facility after sleeve-death, where they can remain indefinitely.
Because of the nominal ability to revive anyone who dies, sleeve-death, so long as the cortical stack remained intact, was reduced to a lower level of legal concern, akin to property damage. Only if the stack was destroyed was such considered death or, if the result of violence, murder. It became common practice for the state to guarantee re-sleeving for victims of accidents or crimes, should they not specify their objection to being re-sleeved, although this re-sleeving was often done using whatever sleeves were available, regardless of quality or appropriateness, unless the individual had made other, usually extremely expensive, prior arrangements.
Care must be taken to avoid real death anything from blunt trauma to energy weapons fired at the head (known as slagging) can destroy a stack.
D.H.F. Backup
There exists a very expensive service for the wealthy, remote D.H.F. backup, that holds and updates a duplicate of the client's consciousness to a separate remote Cortical Stack held in a secure vault. Every so often an update sends the most recent memories and experiences of the client from their current Cortical Stack to their backup stack via the process of Needlecasting, ensuring that even if their current stack is destroyed they have a backup in a secure location with all their memories leading up to the most recent update. These backups are only placed in a sleeve when the original stack is destroyed.
D.H.F. Copy
With the digitization of human consciousness there arose the possibility of copying a consciousness similar to how a computer program is copied, creating a perfect duplicate of a persons mind. Creating a duplicate of oneself within another Cortical Stack is not inherently illegal but placing a duplicate consciousness in a sleeve is called "Double Sleeving" which is highly illegal due to the problematic nature of creating duplicates of oneself and is punishable by real death.
Religious Coding
Because some religions, most notably NeoCatholicism, do not believe that re-sleeving is acceptable, a practice of applying a religious "coding" to a stack was adopted. This coding specifies that the individual is not to be spun back up after sleeve-death, even in virtual reality. Thus those who are coded can not be legally revived (until the passage of Proposition 653.) This does not always prevent it from occurring, however, as desperate family members or others can take action illegally (and under threat of prosecution) to revive coded individuals anyway.
Coding is a personal choice, and can be applied or renounced at any time. Family members are barred from making such a decision, even in cases where the person in question is incapacitated and they are authorized to make other medical decisions. However, because allowing or inducing sleeve-death and re-sleeving is considered standard medical practice in a number of situations, mostly when the effort to save the sleeve would be excessively difficult or expensive, those who have religious coding may find themselves lacking options in the case of some injuries or conditions. Research into a number of conditions and ailments has also not been widely undertaken for similar reasons, though a core of religious doctors continue such research on the fringes for the benefit of fellow believers. Such research is also undertaken by opportunists, looking to be able to charge the religious exorbitant fees for treatment.
Proposition 653 is a new law that overrides religious coding in the event of murder. It was passed after the discovery that coding was being used to cover up crimes (beyond the murders themselves) by tampering with records to apply coding to people who knew details of criminal activity against their will, so that they could be killed to conceal that activity. Because sleeve-death, without the destruction of the stack, was considered a lesser crime, this was effective at concealing more serious offenses.