by Stephenie Meyer
Memory and the Past Quotes in Twilight
How we cite our quotes: (Chapter. Paragraph)
[Edward to Bella:] "We don't really know. Carlisle has a theory…he believes that we all bring something of our strongest human traits with us into the next life, where they are intensified – like our minds, and our senses. He thinks that I must have already been very sensitive to the thoughts of those around me. And that Alice had some precognition, wherever she was." (14.250)
Vampires bring skills from their human pasts when they transform, and those skills become amplified to a vampire-level of strength.
Though, now that I'd chased the memories down, I did the vague impression of leaving the car – the sun was just falling behind the horizon – my arm draped over Alice's shoulder and her arm firm around my waist, dragging me along as I stumbled through the warm, dry shadows. (20.14)
Bella is exhausted and traumatized, so her memory isn't as good as usual.
[Alice to Bella:] "I don't know. For everyone else, the pain of transformation is the sharpest memory they have of their human life. I remember nothing of being human." (20.90)
Alice has no memory of her life as a human – she doesn't even remember her transformation. We later learn that Alice was locked up in a dark asylum as a human, which is why she doesn't remember anything from that time period.