On the wasteful discussions on life after death, Some wise sages have handled after death question very well.
இறப்புக்கு பின்னர் என்ன ? கண்டவர் விண்டிலர் விண்டவர் கண்டிலர்.
The Japanese Emperor asked the Zen Master, Bosho: "What happens to a man of enlightenment after death?"
Bosho replied: " How should I know?"
The Emperor continued: " But you are a Master!"
Bosho replied: " Yes, Sir. But I am not dead yet."
Every human being is born with three types of debts to be repaid, namely,
(1) the debt to Nature/God (that can be repaid by worshipping gods),
(2) the debt to sages and saints (that can be repaid by reverence and service to saints, sages and gurus) and (3) the debt to one’s ancestors.
Everyone will like to pay respects to ancestors.
If analysed logically, Pithru rituals are not for pithrus, but for our satisfaction or mental peace. We have to thanks them or pay respects to them as we owe our ancestors. So, it is called "Pithru kadan" (The Debt to Departed Ancestors).
All connected rituals looks like a take and give account. Some scriptures assume that Soul has retained personality, experiences, actions and so on. They eat, roam, think, and feel bad & happy, like life on earth. So, they can bless or curse.
Pithrus or spirits or Atma is beyond physical world. Heaven, Hell and Pithru loga are abstract concepts like Happiness, sadness, fear and suffering. They are not physical worlds or entities.
In Katha Upanishad, the conversation between Lord Yama and Nachiketa to the questions posed by Nachiketa about the life after death. Lord Yama answers: “All Jeevas originate from the Supreme Reality, like sparks from a fire. They are pure to start with. The Jiva changes due to environment and circumstances, just like pure rain-water is contaminated coming down due to gravity. The Atman, though a passive passenger, gets involved, but still in its essence is pure. It is the contaminants which are carried by it, much as desires and actions contaminate the intellect and ego-enity.” Garuda Puraana”, deals at a great length (in the second half), with the life after death.
Around "Life after death concept", theorey has been developed on future of souls after death, leading to stories/incidents to show souls live like humans after death. Like other civilizations (Egyptian/mesopotomia), there were folk stories that after life, the soul has to travel towards God of death for Judgement and then go to heaven/hell. As we have different forms of diets(foods) , souls are survived and revived by the diets. They move, think, and feel like human beings.Their one day is equivalent to our one-year time. That is why anniversary (in our terms) is taken as day for Pithru karyas i.e. Sraadhaas enabling the soul to have food.
Some of the popular concepts on atma, life and death in HinduCommunity: After death, the soul in its disembodied form hovers about its original and familiar places for ten days. The soul is sustained on its onward march to the judgement seat by the libations (an act of pouring water) offered to it by the son. It starts on its journey to the judgement seat of Lord Yama, the God of death. Different cultures have different routes and time line to reach the God of death. For example Maori of Newzealand believe souls travel through the beach and go to northern most point of the island. Some wise men who have travelled towards polar regions has described tough journeys. So, based on these travle notes, priests propagated the idea that souls go to world (like polar region), where one day is one year, six months day and six months night. Ruling and Priest class develop rituals to ensure society is under their control. In a way some social order is maintained. The spiritually potent mantras that are chanted during these rituals are supposed to have the subtle power of providing momentum to the subtle bodies of deceased ancestors so that they can progress to a higher sub-plane of existence.
There are too many conflicting theories. No one knows what exactly happens after death.
The word sraaddha itself means performing something with full involvement. As long as one has full respect for ones ancestors, the exact form of performance is not important. The rituals itself has changed a lot in the last few years due the current conditions of our living. Of late due to circumstances the Sraadha has been replaced by many with Annadanam, many supplement a short sraadha procedure with Annadanam. Important thing is “Shraddh should be performed with a pious mind”. The person who performs the Shraddh should realize that for his birth, body, knowledge, wealth and sanskar he/she is indebted to the ancestors. All that is there was given by the ancestors. So the rituals performed is accepting this fact and is sort of thanksgiving. Both male and female relatives of the dead can perform the rituals. The method of performing the rituals slightly varies from region to region. But the essence of the ritual is the same.
Stories are created based on after death theories. Some are used by ruling class to create fear among subjects and to make community members to behave as per social norms. To motivate people to do these rituals, we are told, "All sins shall be washed or forgiven by God of death,by giving Gift of cow, Gold, Iron, Land, Food, clothes etc. Gift of land is considred best of all." Some publications create fear like deceased person will suffer if you do not do these and they will curse you.
The most important things is feeding fellow living beings (humans preferably the poor and animals/birds) on the day. Some people distribute food and clothes among the poor and do some charity.