Sri Aurobindo has dismissed the concept of material reward and punishment as being the basis for action underlying rebirth and karma. He now provides the actual rationale under which rebirth and karma are not simply a theory among theories, but an essential mechanism to the operation of life and evolution.
“The true foundation of the theory of rebirth is the evolution of the soul, or rather its efflorescence out of the veil of Matter and its gradual self-finding.”
“And if this gradual efflorescence be true, then the theory of rebirth is an intellectual necessity, a logically unavoidable corollary.”
The reason it becomes necessary is based in the purpose of the soul’s evolution. “Not conventional or interested virtue and the faultless counting out of the small coin of good in the hope of an apportioned material reward, but the continual growth towards a divine knowledge, strength, love and purity. These things alone are real virtue and this virtue is its own reward. The one true reward of the works of love is to grow ever in capacity and delight of love up to the ecstasy of the spirit’s all-seizing embrace and universal passion; the one reward of the works of right Knowledge is to grow perpetually into the infinite Light; the one reward of the works of right Power is to harbour more and more of the Force Divine, and of the works of purity to be freed more and more from egoism into that immaculate wideness where all things are transformed and reconciled into divine equality. To seek other reward is to bind oneself to a foolishness and a childish ignorance; and to regard even these things as a reward is an unripeness and an imperfection.”
The process of the soul’s expression and growth out of Matter, through the various challenges of Life, the developments of Mind and beyond into the Supramental ranges of consciousness is something that is not done in a single lifetime, and it is this process that requires and determines the continual rebirth and which is propelled forward through the chain of cause and effect, karma. That does not imply that a specific egoistic personality is reborn continually; rather that the stream of energy continues and develops through the process of life and death.