| Quote #1
Hovstad: "When I took over the 'People's Messenger' my idea was to break up this ring of self-opinionated old fossils who had got hold of all the influence."
This bit of information hints that Hovstad isn't the principled radical that he tries to sell himself as. When he first took over the paper he tried to really stick it to the wealthy political establishment in town. That, however, ended up jeopardizing his paper so he had to back down. Unlike, Dr. Stockmann, Hovstad just isn't willing to risk everything for his beliefs.
| Quote #2
Aslaksen: "I have the reputation of a temperate and law-abiding citizen." (2.131)
Aslaksen is undeniably a principled man. He believes in temperance and moderation in all things. He sticks to these ideas throughout the entire play.
| Quote #3
Hovstad: "most of the people here are […] so overcome with caution […] that they never dare to take any decided step." (2.152)
Hovstad is basically saying that no one in the town has any principles. They are so worried about upsetting the status quo that they put their own beliefs aside. All this fiery rhetoric from Hovstad is ironic, since later in the play he joins the cautious majority.