It is because man clings to things which cannot fully satisfy him,
such as the love of family, the desire for wealth and fame, the wish
to be reborn in a heaven (all of which are classed together in
Buddhism), that he has to go on being reborn. This is the Buddhist
doctrine of _Kamma_. Hinduism, like much orthodox Christianity, thinks
of a "soul" which dwells in the body. The Hindu thinks of it as
passing from one body to another in the process of transmigration. The
view of Buddhism is rather that the "ego" of man is a stream of mental
energy, the direction of which is under his own control. If he dies
full of _tanhā_, cleaving to the things of this world, he will surely
be reborn to some sort of misery. If, on the other hand, he dies
detached from human interests and open-eyed to the worthlessness of
temporal things, he will eventually be set free from the entanglement
of life, as we know it on earth, and will pass into _Nibbāna_. Of
this goal one can only say with assurance that it is unlike anything
known to mortal man,[10] and that its essence is moral purity.