Retroengineering the development of doctrine

Catholic apologists like to retroengineer the development of doctrine. With the benefit of hindsight, they retrace later positions and policies back to seminal ideas in the church fathers. 

Sometimes that's legitimate, but it an easily be an illusion. That's because it's often possible for the same ideas to branch out in divergent directions. So it's unpredictable. In themselves, the same ideas may have no orientation to a particular line of evolution. 

To take a comparison, consider the character of Batman, Superman, or Dracula. In later creative hands, these are open to a wide range of alternative developments that could not be foreseen or intended by the creators of the character. 

If you know how an idea began, and you stand at a certain point down the line, it may seem more inevitable that it was going to unfold that way. But suppose you didn't know how the character of Batman or Superman or Dracula originated. If all you had to go by were their current permutations, how successful would you be at recovering the Ur-character, with his original history?