I've been noticing how Marianne tends to express her opinions in absolute--always, never, no one, nobody, invariably, impossible etc. People who don't share her opinions don't have a difference of opinion--they are making a mistake. She, and people who think like her (or profess to think like her) is right and everyone else is wrong.

And yet, she can revise her own opinions at will. From Ch. 4, we had "Mama, the more I know of the world, the more am I convinced that I shall never see a man whom I can really love. I require so much!" In this section, we read in Ch. 10 "Marianne began now to perceive that the desperation which had seized her at sixteen and a half, of ever seeing a man who could satisfy her ideas of perfection, had been rash and unjustifiable."

In Ch. 5 we had "Dear, dear Norland! When shall I cease to regret you? -- when learn to feel a home elsewhere?" But in Ch. 11 "the fond attachment to Norland which she brought with her from Sussex, was more likely to be softened than she had thought it possible before, by the charms which [Willoughby's] society bestowed on her present home. "

Sometimes the twists and turns she makes in her thinking in order to believe two contradictory things at the same time defy logic. Believing that second attachments are unpardonable and impossible while still having no ill opinion of her father for having a second marriage is a good example.

Elinor observes to Colonel Brandon that she hopes one day Marianne's opinions will be easier to define and to justify than they are now. However, Elinor also knows that expressing opposition to Marianne's opinions attaches Marianne more firmly to them than ever. Perhaps she has observed that, if left to her own devices, Marianne can find soften her former opinions or even find them 'rash and unjustifiable'.