our existence is not restricted to the period between the birth and death

I do firmly believe the idea found reiterated in Hinduism that our existence is not restricted to the period between the birth and death. even without any direct proof...

Rather, like the blessed lord said in Bagavad Gita, this life material just changes bodies like worn out garments and appears again in new clothes..

The varied stages of growth and maturity in mind and physique we discover among us cannot be explained in any other way..

वासांसि जीर्णानि यथा विहाय

नवानि गृह्णाति नरोऽपराणि ।

तथा शरीराणि विहाय जीर्णा-

न्यन्यानि संयाति नवानि देही ।।२२।।

भगवत् गीता अध्यायः २ साङ्ख्ययोगः

vaasaamsi jeernaani yathaa vihaaya

navaani gruhnaati naroparaani

tathaa shareeraani vihaaya jieernaa

nyanyaani samyaati navaani dehee..

Bagavat Gita chapter two.. sankhya yoga