First, there are clues that John's father is interested in secular learning, and that his private positions on religious matters are not the same as his public positions. This suggests that he may be prepared to take a flexible approach to religious practice.

We see this at the beginning of the story, when John recounts how his father taught him practical knowledge, like "how to stop the running of blood from a wound." When putting such knowledge to use, the priests might also speak chants and cast spells. John's father appears to understand that it's the practical medical technique—not the ritual behavior—that is essential. John's father explains that the rest of the community needn't know.  

"A priest must know many secrets—that was what my father said. If the hunters think we do all things by chants and spells, they may believe so—it does not hurt them."

Second, there are hints that John's father has, like John, had dreams of the gods. His comments and reactions suggest that he has had doubts about the religious stories. He may have even contemplated going to the city himself.

For instance, notice that John says, "It was my father himself who questioned me about my dreams." The wording indicates that it might ordinarily have been someone else who performed this office. John's father seems to have taken a special interest in the subject.

After hearing the details, John's father tells his son this is "a very strong dream" that could "eat [John] up." Then he says:

"Once I had young dreams. If your dreams do not eat you up, you may be a great priest. If they eat you, you are still my son. Now go on your journey."

Finally, when John tells us about his return home, he doesn't give any indication that his father was surprised—not about where John has gone, nor about his discovery that the gods were men. Instead, John's father says something that is consistent with the idea that he had once considered making the journey himself, but felt he couldn't. The law had exerted a greater force on him.

"The law is not always the same shape—you have done what you have done. I could not have done it in my time, but you come after me."