He (presuming it was a "he") certainly didn't know everything, but he knew that isolation brings up all kinds of nasty stuff.
I discovered this early in my solo retreat, as the retreat house filled almost immediately with a crew of unpleasant creatures, chattering away, demanding attention, and commenting on nearly everything I did.
Really, sometimes I had to elbow them out of the way just to go to the toilet.
In everyday life, these beings - call them demons - follow us like shadows. We just don't notice them. We put our attention elsewhere.
However in the solitary confinement of a solo retreat, with little access to the usual distractions, demons come into sharp focus.
And then we're left along . . . with ourselves.