[quote="YoungTradCath, post:4, topic:290111"]
"Differences between Vatican I/Vatican II" is not really a valid comparison. I mean, there are vast differences in what they say, for what they were summoned, what they intended to do, their aftermaths, how they are viewed today, etc. However, you phrase your question as if Vatican I and Vatican II are opposites. They are not.
Vatican I and Vatican II are "ecumenical councils," which are councils of all the world's bishops. Councils can be called, theoretically, for any reason a Pope--or in some cases someone else--wants to call one. However, historically speaking, they are usually called in times of crisis or uncertainty, or when some major contemporary problem needs fixing. Vatican II is the one exception to that last bit, but that is beside the point.
There have been twenty-one ecumenical councils in the Church's history. Some important ones by today's standards are: Nicaea, Trent, Vatican I, and Vatican II. If I'm understanding your implications correctly, you perceive some conflict or hesitancy, so to speak, about Vatican II. You would be correct. However, it still would not be right to say or think that Vatican II and Vatican I are opposites. Their naming is purely incidental. It's not like, "Vatican I said ___, Vatican II went and changed __," or anything like that.
Rather, given what you've posted so far, this is what I will say:
Vatican II happened between 1962 and 1965. Through a whole system of unfortunate events (nutty Sixties, cultural problems, misunderstandings, an overzealous and borderline fanatic optimism, near complete disintegration of catechesis, focus on odds and ends rather than the central parts of the faith, etc.), Vatican II turned out to be, in my opinion, The Council That Probably Needed To Happen But Which Was Doomed For Very Troubled Times. Basically, Vatican II asked for some changes in the Church, for various reasons. To varying extents, these things happened.
However, what is now commonly called a "hermeneutic of discontinuity" emerged. Basically, in this view, some people took things waaaaaaaaaaaaaaaaaaaaay too far. I can't really phrase it more succinctly than that. And I don't want to go much further because I'm sure others have things to say.
I should note that this is a massive subject...
Vatican II was declared by the Popes as a pastoral council.
It dealt with pastoral issues and not with doctrinal issues (there were no anathemas, etc).
Vatican I declared as dogma that the Pope was infallible.
Vatican II did not seek to create any new dogmatic statements.
This is where the confusion lies.