What is the purpose of incarceration?

What is the purpose of incarceration?

Is the purpose of incarceration to remove individuals from society for crimes they have committed, or is it to help facilitate reform and change behaviors; so that individuals can return home once restitution has been paid?

Prison affects more than just the individuals; what about the inmates’ family?

Are there any programs that you would propose that could help both inmates and their families during incarceration?