It is characteristic of great artists generally, and of great writers in particular, to have a discerning view of the basic social and political arrangements of the society in which they live.
Conclusion (Therefore)
The greater a writer one is, the more astute one will be in perceiving the basic social and political arrangements of one's society.
Evidence
It's a characteristic of great writers to have a discerning view of the basis social and political arrangements of the society in which they live.
Evaluate
This argument is a little weird. It's sort of like this:
It's a characteristic of great athletes, and of great basketball players in particular, to be tall. Therefore, the greater a basketball player is, the taller they are.
It's taking a trait that is associated with great writers but then turning it into this incredibly strong Volume Dial idea (the more x, the more y).
Just as we saw with the basketball example, the fact that a quality is associated with something doesn't mean it's associated directly proportionally!
Goal
Look for an answer describing this distinction between a generalization (great writers are astute observers of the sociopolitical arrangements of their society) and a proportional relationship (the greater you are, the more astute you are).