Originally Posted by
Lonewolf_50
infrequent flyer: this is a wirehead question in two parts, but I'll ask anyway.
1. What parameters inform (other than sidestick command, or in mechanical back up mode the trim wheels) how the THS moves up or down?
Afraid you are crediting me with more detailed knowledge than I actually have.
Short answer - I don't know, but it is one of the questions on my mind too...
I strongly
suspect that airspeed is in there somewhere, but what value is used when airspeed is known-invalid, I have no idea.
Regardless of pilot inputs, the computers will prevent :
- excessive maneuvres
- exceedance of the safe flight envelope
And the concierge can fly it too... 
All missing the big caveat "as long as everything works normally" (and actually, even then the concierge quote is rubbish). Drop out of normal law and all that no longer applies.