The feeling inside them must have a meaning. They are trying to move forward by questioning themselves without knowing if they are standing still or just going forward. They couldn't describe this feeling, it's something much deeper and gnawing inside. This feeling that makes them question their existence is perhaps just a "nothingness". It never actually existed, but they want to experience it because "they feel alive only because they can feel". They are trying to deal with a feeling that was never there. Without knowing that "nothingness" comes from inside.