We need a life after death, because complete justice cannot be established in this world. Let us see a few examples.
Some people believe that there is more than one Creator or God for this world OR at the very least they argue that there is One God along with several other demi-gods (Devataas). This philosophy is called “Polytheism”.
Man has been created in a very natural manner but he has failed to go along with his nature and has indulged into many unnatural things which are leading him to stress, problem and tension.