The Inspector is quite a flat character in the sense that he does not change or develop during the play. He remains constant to his task of revealing, if not an actual death, then the moral failings of each of the other characters, which can have fatal consequences. He is the catalyst for the change in Sheila and Eric, however.
He is an imposing figure who has
an impression of massiveness, solidity and purposefulness
as highlighted in the stage directions. His presence is imposing and intensely disconcerting for the other characters as he reveals their lies and social weaknesses.
The Inspector appears to be omniscient and omnipotent – all-seeing and all knowing. This is how he seems to be the voice of morality and social conscience when he addresses the characters.
We are members of one body. We are responsible for each other.
Goole is also a pun on the word ‘ghoul’, and we are told that when Birling telephones the Chief Constable, there is no knowledge of an Inspector Goole. He seems to already know the answers to the questions he poses, and makes judgements on the characters which seem to go beyond the usual impartial questioning one would expect of a police officer-
Well, Eva Smith’s gone. You can’t do her any more harm. And you can’t do her any good now, either.