In "The Crucible", how does John Proctor show a voice of reason?

We see John's reason in some of his first interactions with the townspeople.  Parris bemoans that people are spreading rumors about witchcraft, and John states simply, "Then let you come out call them wrong."  Putnam insists children are dying, and Proctor says, "I see none dyin'".  He is the first to voice the reasonable argument that of course people will confess if they avoid hanging:  "There are them that will swear to anything before they'll hang; have you never thought of that?"  He considers Mary having sewn the poppet reasonable proof enough to dismiss the officials from his house: "Bid him begone.  Your mind is surely settled now."  He asks the very pertinent question:  "Why do you never wonder if Parris be innocent, or Abigail?"  He leads the many attempts to prove the girls a fraud (the petition, Giles' testimony, Mary Warren), eventually ousting his affair to show that vengeance is at play:  "it is a whore's vengeance, and you must see it."  When they try to post his confession to the church door he logically proclaims, "God does not need my name nailed upon the church!...I have three children-how may I teach them to walk like men in the world, and I sold my friends?"

These are just a few examples of John's reason, logic and common sense, that unfortunately did not hold back the tide of hysteria and accusations.