Mr and Mrs Birling are holding onto a pretence and are proud and do not want to be proven wrong. Unlike Sheila who has become humbled through this conversation in the evening. After the family discover that the Inspector was a hoax, Sheila still does not believe he came to trick them; she thinks he came to teach the Birlings and Gerald a lesson about unselfishness and caring for others rather than themselves. She says that the facts are still the same, that the family were still very selfish and uncaring.
Sheila is the character who has learnt the most. Her refusal to retake the engagement ring shows that she has matured at the end of the evening. She approaches Gerald in a different manner, as she now understands that she doesn’t know Gerald properly, the way she should. She has to start all over again to get to know him. She realises that she and Gerald must be honest with each other if there’s to be any relationship between them. She says, “You and I aren’t the same people who sat down to dinner here. We’d have to start all over again, getting to know each other…”
There could be many explanations for why Sheila Birling responding to the Inspector’s ” and why her father Mr Birling did not. Sheila reacted very positively and understood the Inspector because the Inspector was asking at her lever; a level that she would understand. Sheila is more of a sensitive character and is very vulnerable; someone can very easily make her change her views. Since she is still young, and she is not set in her ways, she has not yet created her own philosophies and ideas as her father has; she can be influenced by the opinions of other, especially as this Inspector had an imposing presence and also used very emotional tactics to convey his message. As proven at the end of the play, the “Inspector” was in reality not an Inspector. The author leaves us in suspense as to who this may be. I believe, Mr Goole could be a socialist who has been studying the case of Eva Smith for many years and now realizes all the trouble she has gone through, decides to teach the Birlings a lesson, as to show them how selfish they are.
He could also be a prophetic character from the unreal world, like for example, an angel or a fairy come on behalf of the poor oppressed young Eva, again solely to teach the family a lesson. Mr Goole could also be a friend or relative of Eva Smith who cares about Eva and is very upset and angry about how she has been treated, therefore comes to avenge her oppressors in some way. He could be some sort of prophet or messenger come from God to avenge the poor girl and to teach the Birlings something important.
He could be a polite Inspector from another district who came to work on the case. J.B. Priestley is a sociologist and in the play, the Inspector expounds many socialist ideas about having a fair world, etc. Therefore, the Inspector is representing Mr Priestley as a sociologist to convey his message to viewers. The Inspector’s voice is also the author’s voice; all the author’s ideas and philosophies are portrayed as correct with the help of the Inspector and Mr Birling, who is a capitalist and proven wrong at the end of the book.