Reverend Hale has a role that helps to demonstrate how easily and even innocently "false accusations, manifestations of mass hysteria, and rumor-mongering" can take hold of a community.
Hale is a man of integrity and of faith. He believes that he is also somewhat scientific in his approach to witchcraft, as seen in the scene where he is introduced in Act I. Despite these positive traits, Hale is fooled by Abigail's lies as quickly as everyone else.
Additionally, Hale fails to be convinced that Abigail and the girls are lying when he is initially presented with this fact. When Hale comes to investigate/accuse Elizabeth Proctor of witchcraft, he believes that he is acting with the utmost integrity and honesty.
Even in this moment, the audience realizes that Hale is not being honest and that he is dominated by the popular view and, for a while, powerless against that popular view. He was an honest man, but he has become a hypocrite in his agreement with popular lies.
Hale embodies many of the moral contradictions of the play: he is a man of integrity who, although at times misguided and overzealous, is willing to change his mind when confronted with the truth.
The danger presented in Salem is one of abdication. The group claims the power to judge what is right, what is wrong and what is true when the individuals who make up the group agree not to think for themselves. In a play about how fear can be used to define communities and the harm that this can do, Hale stands as an example of the crisis at the heart of this process.
Hale's character demonstrates this thematic idea: Even good people can be corrupted when they abdicate their own moral judgement in favor of the group.
Hale's inability to perceive—and endorse— the power in Proctor's stand for personal virtue leaves his character ignorant and weak.