I don't believe in an afterlife, but i did believe that people go on in the memories of others. I believed that it was important to tell stories of the people of your past to learn from them and their actions and the resulting consequences.
But these two things don't correlate. Learning and thinking about someone is not them living. Sarte noticed it. People are only alive if they are changing.
Never stay the same. If you do, you're dead. Choose to improve or choose to fail, it's just important to choose something. If you don't choose, you end up being a dead entity running on auto for the rest of your pointless life.