What's a 'person'

Last night we watched "Robot and Frank," which I think is a pretty good movie. Rachel thought it was very sad, but we did find ourselves laughing at several parts and had a good discussion afterward.

The basic premise is that an older man (who is fighting dementia) is given a robot to assist him around the house and help improve his health and overall well-being. Frank initially rejects this idea but grows to appreciate the Robot. Early on in their 'relationship,' the Robot tells Frank that it is not a person, it is just hardware and software designed for a specific purpose. But when Frank's kids later refer to the robot as being nothing more than a mechanical slave, Frank responds with, "I need him. He's my friend." At the end of the movie, Frank has to do a factory-reset on the Robot, thereby erasing its memory. The Robot again assures Frank that there is no problem doing so since it is not a person.

But the Robot is a person in Frank's mind! Frank would not have attached himself in the ways he did to the Robot if he really believed it was just hardware and software. And it took the Robot repeatedly assuring and almost even begging Frank to wipe it before Frank finally was willing to do so.

The movie got me wondering 'What makes an entity a person?" I've come to the conclusion that whatever it is, it has to come from either within the entity or be projected onto it from someone else.

"I think therefore I am!" is a philosophical argument that 'personhood' comes from within.

Pro-abortionists believe that fetuses are not people and use arguments that 'personhood' is projected onto them at birth (or at whatever week gestation the particular pro-abortionist draws the line).

Frank obviously projected 'personhood' onto the Robot, but the Robot was the first to admit that it was not a person.

So what is it? Help me out here!