Existentialism
Many religions and philosophies (ways of thinking about the world) say that human life has a meaning (or a purpose). But people who believe in existentialism think that the world and human life have no meaning unless people give them meaning: ‘existence precedes [is before] essence’. This means that we find ourselves existing in the world, and then we give ourselves meaning, or 'essence'. As Sartre said, "We are condemned to be free". This means that we have no choice but to choose, and that we have full responsibility for our choices. Another way to put it is that we are always making choices even if we don't realize it.