Possibles

"Since each of us was copied at some point from a normal person, there must be, for each of us, somewhere out there, a model getting on with his or her life. This meant, in theory, you'd be able to find the person you were modelled from." pg 139

Ishiguro only seems to hint about how exactly these students were created. He reveals that all the students were apparently modelled after someone else, similar to a clone. It must be an advanced world in the England in the 1990s if cloning is going on...

Anyway, it makes sense that the teens at the Cottages contemplate who they are modelled from. If they can seek out their 'possible,' then it gives them a sort of connection to their past life, and possibly can give them a, "glimpse of your future" according to Kathy. Ruth's possible, who works at an office according to the veteran couple, shows us how much the teens long to live a normal life. Ruth goes on about how exciting it would be to work in a nice, clean and organized office. Ishiguro may be trying to make a point here. We should not take our lives for granted--we have so many great things ahead of us, while these teens have one path: organ donation. We have the chance to be a doctor, lawyer, police officer, singer, or anything that we set our mind to. But it's not like that for these teens, and it seems as they grow older they grasp this concept more and more. Ruth wants to see her possible so bad, because she wants to have a glimpse of what could be, how her life may have been if she wasn't a Hailsham student. Ruth wants to know some meaning behind her life, so she doesn't give up on the idea of seeking her possible.