Bhagavad Gita

ಅಥ ಚೈ ನಂ ನಿತ್ಯಜಾತಂ ನಿತ್ಯಂ ವಾ ಮನ್ಯಸೇ ಮೃತಮ್ ।
ತಥಾSಪಿ ತ್ವಂ ಮಹಾಬಾಹೋ ನೈನಂ ಶೋಚಿತುಮರ್ಹಸಿ ॥೨೬॥
atha cai naṃ nityajātaṃ nityaṃ vā manyase mṛtam |
tathāSpi tvaṃ mahābāho nainaṃ śocitumarhasi ||26||

Gist of the sloka:
O Great Warrior, even if you assume that the soul gets its birth and death through this gross body, lamenting for it is still meaningless.
If we leave out the Vedic knowledge and think at the worldly level, then soul has a birth with the body and death after the body falls. In which case to understand the birth and death is near impossible. For them the very nature of soul, is not required to explain the phenomenon. It just the body alive and dead. Why then would you lament, for the body is destined anyways to be destroyed?
You who have fought many great battles never thought of these things before. Why then do you have these doubts now?
May philosophies like Buddhism, modern biologist and material scientists think in similar lines. Their concept is that the various elements in the nature ‘somehow’ in the strange ‘co incidence’ come together and life automatically happens.
They are also unable to explain, how death happens in a body suddenly when its functioning with the death message reaching all the billions of cells in the body in a given instant.
These birth and deaths are happening on the Earth for eons and how many times [hundreds of billions of times] can such co incidence happen without explanation? How is this strange happening generated so many intelligent life forms, wellstructured to suit their individual environments, how can they also do complex reproduction of their own species all due to no external force guiding them?