What it is that the inspector wants or teach the birlings?

The inspector aims to impart a crucial lesson about social responsibility and the interconnectedness of individuals within society. He challenges the Birlings' complacency and self-interest, urging them to recognize the impact of their actions on others, particularly the vulnerable. Through his inquiries, he seeks to awaken their moral conscience and encourage them to take accountability for their role in the community. Ultimately, the inspector’s visit serves as a catalyst for reflection and change in their attitudes toward social justice and empathy.