"And having discovered that opportunism does fail, I have been induced to look at it more largely, and in consequence to see that it must fail. I perceive that it is far more practical to begin at the beginning and discuss theories. I see that the men who killed each other about the orthodoxy of the Homoousion were far more sensible than the people who are quarreling about the Education Act. For the Christian dogmatists were trying to establish a reign of holiness, and trying to get defined, first of all, what was really holy. But our modern educationists are trying to bring about a religious liberty without attempting to settle what is religion or what is liberty. If the old priests forced a statement on mankind, at least they previously took some trouble to make it lucid. It has been left for the modern mobs of Anglicans and Noncoformists to persecute for a doctrine without even stating it."
(Chesterton. "Hertics". Introductory Remarks.)
We see that Chesterton is still laboring with the concept and need for definitions. It would be the theme of the introductory remarks.