"Thinking is a form of feeling; feeling is a form of thinking." Susan Sontag

All script analysis, intellectual effort, is really emotional preparation. Thinking is an emotional endeavor as well as a cerebral one. To stimulate the mind, one has to be in contact with the emotions which are allied and precede thought. That is why thinking is often physically (read: emotional) exhausting work.

So when an actor is trying to "understand" the script in their analysis and rehearsal, the effort is not a purely intellectual activity. They are trying to emotionally identify with the work. Proof in point: when an actor refuses to emotionally connect with a character--or a character moment, or the whole script, for that matter--they generally say: "I don't understand it!" Sometimes: "It's a stupid script!" Meaning: I refuse to stretch my emotional acceptance of reality in such a way to embrace any personal identification with the character or scripted action. Playing Hitler, rapists, Bin Laden, child molesters, etc. with honesty, depth and authenticity comes to mind.

A fine actor is one who is able to stretch their emotional acceptances of themselves, and through themselves, others. One who refuses, either out of laziness or fear, to do that will be limited in their role playing possibilities. To "understand" a script is to understand and accpt oneself, and see and embrace the emotional undercurrents that run similarly through the character and you.