Yeah. It's an interesting place to visit. I also believe that originally a "penitentiary" referred to a prison where prisoners were held in solitary confinement, with the goal of reform, or 'penance.'
But we should remember that solitary confinement is almost universally worse than other forms of punishment, in terms of the mental toll it takes upon the inmate. The Wikipedia page is a good place to start: https://en.wikipedia.org/wiki/Solitary_confinement#Historica...
> While some have argued that the Pennsylvania System was Quaker-inspired, there is little evidence to support this; the organization that promoted Eastern State's creation, the Society for Alleviating the Miseries of Public Prisons (today's Pennsylvania Prison Society) was less than half Quaker, and was led for nearly fifty years by Philadelphia's Anglican bishop, William White.
