Sheila clearly has begun to change. She owns up to her responsibility for Eva’s death, maturing as she does so. Notably, she stands in stark contrast to her mother, who refuses to change at all and (so far) refuses to drop her mask of icy, upper-class politeness. Priestley is interested in the well-worn idea that the young have the capacity to change, accept new ideas and move forwards while their parents and the older generations often fail to do so.
Shortly before his exit, we see that Sheila similarly has the maturity to, without tears, accept that things are now different between her and Gerald, even unemotionally offering the symbolic gesture of the return of his ring. Maturely, she accepts her part of the responsibility for Eva’s death, noting that it is better that “at least [Gerald has] been honest.” Moreover, as she points out to him, “this has made a difference,” and the engagement will not be able to continue without serious reconsideration.
The moment when Sheila returns Gerald’s ring perhaps symbolizes the distance the play itself has come: it’s comfortable “engagement party” opening has been entirely turned on its head. In addition, the man who was assumed (by Birling) to be just a local, Brumley police inspector has turned out to be something quite different. Sheila has been the first to realize the strangeness of the Inspector. “I don’t understand about you,” she says to him, while Priestley’s double adverbs (in his stage direction) to direct the actor are “wonderingly and dubiously.” It is Sheila who first suggests, later in the play, that the Inspector might not have been an Inspector, and here she is already beginning to suspect that there is something unusual about him. Sheila, moreover, is aware of the fact that the Inspector is now going to control events until he leaves, regardless of what either of her parents tries to do to oppose him.
The Inspector himself is a fascinating character. As the title character, in many ways he is the most important character to any interpretation of the play. Priestley describes the Inspector on his first entrance as creating “at once an impression of massiveness, solidity and purposefulness.” He is in his fifties and has “a disconcerting habit of looking hard at the person he addresses before actually speaking.” The Inspector elliptically comments that he does not “see much of” the Chief Constable in Act One, which is unsurprising, given that he is not (as we find out in Act Three) actually a police officer. One of the key questions of the play is the precise nature of the Inspector’s identity.
It is possible, of course, that the Inspector is perfectly human and unremarkable, as Birling says: a clever hoaxer, making the most of some information from the girl’s diary. Yet, this would not explain the arrival of the police inspector at the end of the play! Moreover,...