It would be disappointing to think that Catherine is regressing - that her recent good sense regarding John Thorpe was just a flash in the pan. But I'm inclined to give her the benefit of the doubt for being a steady improver, on this basis: her infatuation with 'horrid' fiction is an older folly coming to the surface, not a newly acquired folly. It started in chapter 5 or 6, but was in abeyance all through the chapters that mentioned Blaize Castle, and only found an outlet in Volume II. (Go on, Catherine, get all those defects out in the open and then get rid of them. Good girl.)
Something that struck me this time was Henry's If the effect of his behaviour does not justify him with you, we had better not seek after the cause
in chapter 27.
We hear him repeatedly come out in favour of free thinking: He knows what he is about, and must be his own master
(ch19), Nay, if it is to be guesswork, let us all guess for ourselves
(ch19), Consult your own understanding, your own sense of the probable, your own observation of what is passing around you
(ch24), et cetera.
This contrasts with his constrained circumstances. His past behaviour must have been quite conciliatory, so as to accustom his father to no reluctance but of feeling, no opposing desire that should dare to clothe itself in words (ch30). Or, as BarbaraB put it, it's probably something the general's family has been doing for a long time to keep the peace.
That is to say, one does what one must, but thinks what one chooses.
Another of my favourite Austen characters, Elinor Dashwood, might well agree.
S&S ch17>
"But I thought it was right, Elinor," said Marianne, "to be guided wholly by the opinion of other people. I thought our judgments were given us merely to be subservient to those of our neighbours. This has always been your doctrine, I am sure."
"No, Marianne, never. My doctrine has never aimed at the subjection of the understanding. All I have ever attempted to influence has been the behaviour. You must not confound my meaning. I am guilty, I confess, of having often wished you to treat our acquaintance in general with greater attention; but when have I advised you to adopt their sentiments or conform to their judgment in serious matters?"