How we cite our quotes:
[Edward to Bella:] "I know that at some point, something I tell you or something you see is going to be too much. And then you'll run away from me, screaming as you go." [Edward] smiled half a smile, but his eyes were serious. "I won't stop you. I want this to happen, because I want you to be safe. And yet, I want to be with you. The two desires are impossible to reconcile…" He trailed off, staring at my face. Waiting. (16.52)
Edward feels fate has dealt him a bad hand – a total catch-22. Edward decides the best compromise is to let himself be near Bella, and try his hardest not to think of her as a "piece of meat." However, since he seems to be unable to leave her, he hopes that she will make the decision herself.
[Edward to Bella:] "They're still there." He shrugged. "As they have been for who knows how many millennia. Carlisle stayed with them only for a short time, just a few decades. He greatly admired their civility, their refinement, but they persisted in trying to cure his aversion to his 'natural food source,' as they called it. They tried to persuade him, and he tried to persuade them, to no avail. At that point, Carlisle decided to try the New World. He dreamed of finding others like himself. He was very lonely, you see." (16.62.1-9)
Carlisle is defined by his choice to maintain his human-free diet. Most vampires, as Edward tells Bella, have a completely different philosophy from Carlisle's. Though Carlisle's decision has led to isolation, he has stuck to what he believes is right.
"I thought I would be exempt from the …depression…that accompanies a conscience." (16.80.2) Edward to Bella
Edward had gone through a "teen" rebellion but felt bad about his rebellious choices (i.e., breaking the Cullen diet).