If damaged or endangered parts of the brain, like the body, could be replaced with functionally equivalent simulations, some individuals could survive total physical destruction to find themselves alive as pure computer simulations in virtual worlds.
Conscious inhabitants of simulations experience their virtual lives whether or not outsiders manage to view them. They can be implemented in any way at all.
A possible world is as real, and only as real, as conscious observers, especially inside the world, think it is!
Mathematically, any interactive mechanism, even a robot or human, can be viewed as a compact encoding of a script with responses for all possible input histories.
The soul is in the abstract relationships represented, not the mechanics of how they are encoded.
By our choices, we each thread our own separate way through the maze of possible worlds, bypassing equally real alternatives with equally real versions of ourselves and others, selecting the world we must then live in.
Our own nature, in fact, is defined by the tiny fraction of possible interpretations we can make, and the astronomical number we can’t.
Human-spawned intelligence will expand into space, until the entire accessible universe is inhabited by a cohesive mind that manipulates events, from the quantum-microscopic to the universe-macroscopic, and spends some of its energy recalling the past.
It is no surprise that we find ourselves operating at the liquid boundary of chaos, for we could not function, nor have evolved, in motionless ice nor formless fire.
In our daily meanders, we are more likely to stumble across a particular small number (say “5”) than a particular large one (say “53783425456”). The larger number requires far more digits to simultaneously fall into place just so, and thus is far less likely. Similarly, although we exist in many of all possible universes, we are most likely to find ourselves in the simplest of those, the few that require the least number of things to be just so. The universe’s great size and age, its physical laws, and our own long evolution may be just the working of the simplest possible rules that produce our minds.