In response to Zachary’s claim that everything except the original fresco work must be stripped away in order to restore the Sistine Chapel to the appearance Michelangelo intended, Stephen points out that it was common for painters of that era to add painted details to their own fresco work after the frescos dried.

Stephen counters the position held by Zachary. He does this by questioning an assumption that underlies Zachary’s argument. Zachary assumes that Michelangelo didn't intend for the painting to show anything other than the original fresco work. But, if it was common for painters of Michelangelo’s era to add details to fresco works after they had dried, then it may be that Michelangelo himself made some additions to the fresco work in the Sistine Chapel. If this is true, stripping away everything but the original work would not achieve the appearance Michelangelo intended.