"he remembered his former lives"

The Hindu scholar Patañjali discussed the concept prati-prasav (literally "reverse birthing”) wherein the soul carries the burden of impressions of karma accumulated from his past life. Prati-prasav, or past-life regression is today used as a form of yoga, and a meditative technique.

Osho talks about the Prati Prasav Process in Yoga - 'Prati-prasav' is a beautiful word; 'prasav' means birth. When a child is born it is prasav. Prati-prasav means you are again born in the memory, you go back to the very birth, the trauma when you were born, and you live it again. Remember, you don't remember it, you live it, you relive it again." Osho has related the concept of Prati Prasav with Dr Arthur Janov's theory of Primal Therapy.

Prati- Prasav as an ancient meditation technique was given by the Buddha to his disciples:

Before going to sleep, begin to count slowly to yourself a series of simple numbers, backwards and forwards, such as 2, 4, 6, 8 10--10, 8, 6, 4, 2. Continue this repetition rhythmically. Having got this rhythm moving, almost but never quite automatically, deliberately try to picture yourself as you appeared on getting up that morning.