Why we often should persist in our folly

The line here is from William Blake's Proverbs of Hell (1790), which I encountered thanks to Fools Paradise by Paul Hertz in the DiMoDA collection part of Float's Sim-Cinema exhibit.

William Blake,Proverbs of Hell,Fools Paradise,Paul Hertz,persistence,follow-through,finishing,DiMoDA,Sim-Cinema,float,If the fool would persist in his folly he would become wise,