I was reading a book the other day and happened to read about a condition which struck me as oddly reminiscent of the situation Jehovah's Witnesses may come to resemble for failing to see that "New Light" isn't.
Anton–Babinski syndrome is a rare symptom of brain damage occurring in the occipital lobe. People who suffer from it are "cortically blind", but affirm, often quite adamantly and in the face of clear evidence of their blindness, that they are capable of seeing. Failing to accept being blind gets dismissed by the sufferer through confabulation. It is named after Gabriel Anton and Joseph Babinski.
To quote Jesus.
"...If in reality the light that is in you is darkness, how great that darkness is!" - Mt. 6:23