"In" versus "of" when talking about progress?

This maybe overly technical, but that is just the way I am. I am writing a paper for my history cl and I am trying to determine the proper pronoun to use. I want to say "The radical progression in/of western civilization led to..." I am far from a grammarian, so my understanding of the subject is not that extensive. However, after yzing it, the only real difference I can determine between these two pronouns, in this specific case, is that "in" gives a internal connotation and "of" gives more of an external one. If that is true, then I guess the next question becomes whether progress is internal or external. Or is it dependent on the context? For example, the phrase “the progression OF the man" is external and implies physical movement towards a goal, where as the phrase "the progression IN the man" is internal and implies some sort of spiritual or mental development. So, in this case, is a civilizations progress external or internal? After writing all this I am leaning towards internal, since the society didn't physically move, but is physically moving the only way progress is external?