"All of the traditions that came out of India - Jainism, Hinduism, and Buddhism - center on the idea of reincarnation. This is just as fundamental to Indian mythological thinking as our idea of Judgment, Heaven, and Hell is to our tradition. The notion is that the soul - what I will call the reincarnating monad - puts on bodies and takes them off, over and over again, as a person puts on and removes clothing.
"What is the function of the body? The function of the body is to put your "jiva," your deathless soul, into the realm of temporal experience. The body is meant to stimulate the soul with challenges, and then, once the "jiva" has assimilated the possibilities inherent in the experiences of this lifetime, the body is flung away and another body is taken on ...
"Now the individual soul may resist these experiences, in which case it fails to benefit from this lifetime. In this case, the soul is thrown right back like an undersize fish until the soul has learned the lesson. The ultimate goal for the soul is to reach the point where it does not need to put on a body anymore. It is released, to be not anybody, anything - to become one with the light.
"What is it that brings the soul back, putting on bodies like a shopper at Macy's trying on scarves? It is desire and fear. You have a desire for life; you have a fear of death. When you absolutely quench desire and fear, those things by which all of us live, then there is no life. That is the ultimate aim of all the yogas. Of course you can go through all kinds of exercises and think you have gotten rid of fear and desire, but the very fact you are trying to get rid of them is a desire. That is the funny twist that every monk runs up against: the harder you try not to want, the more you're wanting not to want, and so you are in a double bind. The illumination comes when you are least ready ... This moment of illumination comes when you're not quite watching for it; often, when you are striving you are actually blocking it.
"Jiva," the Sanskrit word for this reincarnating entity, is related to the Latin "viva." This is the living force that keeps putting bodies on. Now, on a higher level, since all beings are manifestations of that ultimate being, "jiva-atman," all "jivas" are manifestations of the "atman," and if you will realize that this is "nirvana," you will lose that will to get loose and you will be loose while alive. That business of being in balance while moving in the world is key to this. Now, this is a balance; one reason that athletics and things like music performance and dance performance are so helpful as disciplines is that to do these things well you have to both be doing them and not doing them; there has to be a kind of relaxation and turning the activity over to the body, to the performing power, so that your consciousness rides along with it. That is very much like the saintly attitude. The still point rests in the middle and the activity swirls round about, and you are both the nirvanic point and the activity. The point where the Buddha sat is called the immovable point, but it is the world just as the hub is part of the wheel, and that's because of the nondual realization we get on the other side."
Joseph Campbell, Myths of Light, pp. 44-46