I'll divide my own answer in three sections.
What is it to be "human" (what is it to be "somebody") is obviously a philosophical question, but it is first of all a question that has an existential urgence for any living being whose mind finds itself entangled in self-referential thoughts that they can't control. This is a quality that can, in principle, be artificially (as in technically, by virtue of τέχνη) produced in a physical body. The success of such project has to do with technological sophistication, but mostly with philosophical creativity, as was the case with the invention of the computer. Of course, to talk about it now, as if something so distant from our current experience had already been acomplished, can only be a hypothetical exercise.
The question could be reframed by assuming that, in a way, all sentient minds are by necessity "artificial", in that they are accidents, or singularities, not belonging to any natural genus by virtue of that quality. The awareness - or lack thereof - of this frail condition would be the predisposing condition of disease ("dis-ease"). In that sense, disease is the normal human condition, as has already been defended by many, if not most, philosophers. I'll tentatively postulate here that a greater awareness predisposes to depression; smaller or absent, to psychosis; inadequate understanding, to neurosis; misplaced, to sociopathy.
Inevitably, the distribution of mental disease in a human population is a historical process. As with any complex system, it is extremely sensible to initial conditions. Local equilibria can be reached, but in the grand scheme of things, these are bound to be ephemeral. We may be living one of those moments of great instability. The concept of an "artificial" intelligence (as the one of an "extraterrestrial" intelligence) could be read as an attempt to normalize what is foreign to our present equilibrium. A futile attempt, if you ask me.