Regardless of the existence or non-existence of the ghosts, the governess in Henry James's 1898 Turn of the Screw displayed a case of full-blown paranoia. The 1961 film The Innocents, directed by Jack Clayton, portrayed it in black and white. However, this paranoia would look vastly different if the presence or absence of the ghosts could be confirmed. If the ghosts were real, the governess (Deborah Kerr) jumped to conclusions in assuming that they meant harm. If the ghosts did not exist, the governess had allowed the paranoia to overrule her soundness of mind. In either case, the governess was at fault for allowing her paranoia to dictate her actions.
If the ghosts of Peter Quint (Peter Wyngarde) and Miss Jessel (Clytie Jessop) were truly present at Bly, the governess did them a grave disservice. Once Mrs. Grose (Megs Jenkins) confirmed that Peter Quint was dead, the governess immediately assumed that he was up to no good. However, he had done nothing threatening or evil at that time. There was no solid proof that the ghosts were maleficent. Certainly, the children, Miles Martin Stephens) and for Flora (Pamela Franklin), were indeed acting strangely. However, the governess instantly guessed that the ghosts were behind the bad behavior. For all the reader knows, the children could have always had a bad streak. In this case, the governess let her paranoia get out of control before she had concretely determined that the ghosts had bad intentions.
If the ghosts did not exist, the governess allowed her paranoia to invent them. She was looking for a way to explain the weird behavior of the children. After she came to believe in the existence of the ghosts, she interpreted all the events in the household through that lens. The paranoia prevented her from seeing any other explanation for the phenomena. Perhaps another explanation would have presented itself in time if she would have waited longer before assuming the strange occurrences heralded the presence of ghosts. In short, she was directly responsible for the death of Miles and for Flora losing her mind.
In either case, the governess is to blame for the fiasco at Bly. An educated woman should have known better than to give into paranoia so easily. No matter the status of the ghosts, the governess brought down destruction upon Bly.