Argument for Authority
Not proof but a strong clue
Almost every person ever has believed in life after death. With the exception of certain cultures in the last couple hundred years.
Children are conditioned into not believing in life after death
Argument for Desire
Everyone wants to defeat death.
All other desires link to something physical.
If there is no eternal life why is there a longing for it. All other desires have a physical counterpart for example hunger and food
Argument for Soul Having Parts
We are a body soul union
When we die our souls and bodies separate
While earthly things can kill the body the same can't be said about the soul. Therefore the soul is immortal
Argument from Reason and Free Will
Our souls must be spiritual cause they can perform spiritual acts, therefore our souls are immortal
We can see eternal truths, choose between rights and wrongs.
We don't train humans like we train dogs, a spiritual act can only come from a spiritual actor.
Argument from God
If there's no after life there's no God
If there's a God then immortality must exist.
Immortality comes from God's love.
Argument from Intrinsic Value of the Person
Like the argument for authority much of a stretch.
Without life after death we can be treated similarly to a car.
Once you see a persons true value you see thier immortality