"If Lizzy had been more clearheaded..."

Note end of Ch 16:
"Whatever he said, he said well; and whatever he did, done gracefully. Elizabeth went away with her head full of him."
Again at Netherfield, "She had dressed with more than usual care, and prepared in the highest spirits for the conquest of all that remained unsubdued of his heart, trusting that it was not more than might be won in the course of the evening."
She is not only less clearheaded, she is enthralled with him. This is a form of the second P to the nth degree. No one else's thoughts or opinions will carry any weight at this time.