It is St. Thomas's way to speak of mysteries in terms of distinctions, universal notions, the intellectual faculty, and so forth. It is Fr. Farrell's way to speak of mysteries in terms of how a man reads the morning paper. It is Disputations's way to speak of mysteries by taking things a bit too literally and turning them into poorly-rendered graphs.
If, then, we accept that the act of faith is thinking with assent, we might construct a "faith plot," with one axis representing an increase in thinking and the other an increase in assent:
The four corners of the plot represent four extreme states one can be in with respect to faith -- and to this point, it can be faith in pretty much anything.
What the diagram as rendered suggests is that if you get too far from the diagonal in any direction, you're no longer talking about an act of faith. A little thinking with a little assent produces a little faith, but adding a lot more assent doesn't preserve or add to that little faith, it converts it to zealotry. It's sort of like cooking, where mixing two ingredients in different proportions yields completely different results.