Sri Aurobindo has provided us a succinct summary of the meaning and functioning of rebirth and karma within the manifestation.
“The self-effectuation of the Spirit in the world is the truth on which we take our foundation, a great, a long self-weaving in time. Rebirth is the continuity of that self-effectuation in the individual, the persistence of the thread; Karma is the process, a force, a work of energy and consequence in the material world, an inner and an outer will, an action and mental, moral, dynamic consequence in the soul evolution of which the material world is a constant scene.”
With this principle stated, the rest remains a matter of the detailed methodology of this self-effectuation and the actual working out of the various details of the law of karma and the process of rebirth. We can expect that the details will act to carry out the larger meaning and intention of the manifestation of the Spirit.