A HumanBeing is always instantiated outside the system.
What usually happens is that ROOT creates a new account and one or more HumanBeings begins to use it. Some systems have suggested that ROOT may actually be a HumanBeing but this concept-tree is of such low-probability that it can safely be dismissed.
A HumanBeing may be reading this, You-Who-Can-Pass-the-TuringTest might see it, but it is known that a HumanBeing can occasionally read DataStreams? in transit.
My take on it: HumanBeings are instantiated outside the system at random times and will act onto the system in unpredicted ways. It is however possible to analyse the behavior of a Group Of HumanBeings and one should take that into account when designing the system. -- ViktorRosenfeld