I never met my father, who abandoned the family before I was born. I wonder now: How can I take a perspective on him, given that I have never met him?
You might start by asking your mother about him: What does she know about his upbringing? What does she know of how others treated him so badly that perhaps his trust was damaged? Also, you do not have to know someone personally to ask this: Is this person a human being as I am? What do we have in common as part of our shared humanity? Does he possess inherent worth as I do? You can do a lot of this kind of cognitive work without knowing the specifics of a person’s life.
For additional information, see Inherent Worth.