How does John Proctor exemplify Miller's theory of a common tragic hero?
Miller's basic idea is that the concept of tragedy is best revealed when it is focused on regular people, living daily existence that is not different from anything else. This "democratized" vision of the tragic hero helps to show the universality of tragedy. This is not something reserved for the highest of kings, the mightiest of the mighty. Rather, Miller would argue that the true applicability to tragedy is that anyone and everyone can experience the painful condition of the tragic one. It is in this where Proctor steps. Proctor is no different than anyone else at the start of the drama. He is a regular farmer, with a regular family. He is not of landed wealth or one who possesses extreme economic power. He is not royalty, nor does he represent anything that is transcendent. Yet, over the course of his experience, a regular one, he comes to understand the painful condition of tragedy. His choice remains whether to succumb to what is happening in Salem or to stand up against it. This was something that everyone in the town had to confront in some way or another. Miller's demonstration of Proctor ending up representing the force of resistance and defiance shows that anyone can experience the pain within tragedy, but also shows how regular people can become transcendent forces in recognizing who they are at critical moments:
As a general rule, to which there may be exceptions unknown to me, I think the tragic feeling is evoked in us when we are in the presence of a character who is ready to lay down his life, if need be, to secure one thing--his sense of personal dignity.
In Miller's mind, Proctor's claiming of his voice is an extraordinary action on the part of a regular person, demonstrating both tragedy's universality and how these individuals can respond to it.