According to Lord Krishna in the Mahabharata, the universal law of death and birth is that consciousness is never destroyed. This is a simple point, but its ramifications are complex. It accords with the notion of reincarnation in Hinduism—when one dies, one is reborn as something or someone else, meaning that death is not final and absolute and should not be the subject of grief or despair as it is in certain Western traditions. However, consciousness is clearly not continuous from life to life, since few people would claim to be able to remember their past lives.
Krishna's explanation of the persistence of consciousness and the illusory nature of death is in the Bhagavad Gita, a section of the Mahabharata in which he counsels Prince Arjuna. Arjuna is worried about the number of people who will die in the coming war, and he wonders whether he can possibly be justified in causing so many deaths. Krishna, however, tells him that one should neither cling to life nor grieve over death, since nothing essential is lost in passing from one state to the other. Even though memory does not persist from life to life, the essential part of consciousness, the experience of being alive, will never be lost.