Now, logic dictates that if you identify with an apparition, you have an existential problem when it disappears. I cannot imagine being in such a state, and I doubt any normal person can. But it is well documented that narcissists say they feel "empty inside" and that they feel they "do not exist" when alone that is, when they have no mirror.
This belief reminds one of the stupid question If nobody hears a scream in the dark, did it happen? Or, If nobody sees a planet, does it exist? Many "complex" people answer no. But if that were correct, you couldn't even ask the stupid question.
This comes close to the stupid question Is the moon made of green cheese (instead of moon rock) if you choose to believe that it is? Many "complex" people answer yes. I ask, How can they believe in anything if they do not even believe in Truth? Since the vast majority of them say they believe in God, I ask how they can, since they can create and discreate him at will?
So such beliefs conflict with other things they must believe. But you can't believe two contradictory things at once. Just as in a computer, conflicting information crashes your brain if you don't keep it segregated into different partitions, at least one of which is shut down. Doing that is called compartmentalizing.
To believe known falsehoods and irrational things, many people compartmentalize, but they usually compartmentalize just the stuff they need only on Sundays. A narcissist believes something irrational about his very essence! That fouls up the very foundation and logical structure of the mind. This malfunction must have myriad ramifications in his thought processes.
This is the predicament narcissists are in. Since they identify with their image reflected in mirrors, if their mirrors abandon them, they feel that their very existence is snuffed out. The fate worse than death. Now, a normal person may feel buried alive by total abandonment. But even in that hell, he will say, "I think, therefore I am."
Not a narcissist. Hence, narcissists fear abandonment so much that they are terribly insecure. Also, since they invest nothing but bad-faith in their end of a relationship, they think everybody is as untrustworthy as they. All this makes them so insecure that they have a frenetic compulsion to constantly reassure themselves of your attachment to them by testing its strength.
The only way to test that is by treating you badly to gauge how much abuse you will take. Stupid? or what? What the narcissist thus does to reassure himself of your attachment to him destroys it, causing what he dreads abandonment. And he knows that. But he just can't stop it. Because he is a mental four-year-old who lives in terror of abandonment and can't control himself