Bradbury on "really knowing"

Ray Bradbury., in Something Wicked This Way Comes:

A stranger is shot in the street, you hardly move to help. But if, half and hour before, you spent just ten minutes with the fellow and knew a little about him and his family, you might just jump in front of his killer and try to stop it. Really knowing is good. Not knowing, or refusing to know is bad, or amoral, at least. You can’t act if you don’t know.