This is a facility in Winston-Salem, North Carolina, where people were worried that the building might be structurally unsound from the weight of all that paper.
I could imagine a man who, by living alone and at peace, came to regard the everyday world as not really existent, but a creation of his own fancy in unsound moments.
If the principle is unsound, we have no reason to expect the sun to rise to-morrow, to expect bread to be more nourishing than a stone, or to expect that if we throw ourselves off the roof we shall fall.