As for what common sense is, I'm using it in the "law written on our hearts" sense. Everyone is born with it, even though it gets warped by whatever dysfunctions you might experience growing up, gets miscalibrated and isn't infallible on it's own. Certainly newborns have instincts - to nurse, to emotionally bond with their caretaker - and they have a sense of "my world is right" and "my world is not right", the latter of which leads to crying. Their response to not-rightness is to communicate, and I believe they innately expect that someone will care about their world not being right and do something. Certainly a systemic failure on that front leads to a sense of something missing that can haunt them for life
.
The point is that I believe that dysfunction can warp and twist and generally screw people up, and the earlier it starts the worse the effects - but ultimately people aren't blank slates and underneath all that dysfunction is an innate sense of rightness/wrongness that, however warped it may get, can never be entirely erased
.