One widespread notion about the soul is that it is created with the birth in this lifetime, but then exists eternally into the future. In this view, there is no precedent for the circumstances into which we are placed, and it is nevertheless our responsibility to deal with these circumstances and make the best of them for the benefit of our (future) eternal existence (however that is envisioned).
The idea of an eternal future without a past is a logical inconsistency. Sri Aurobindo describes the issue as follows: “It involves the difficulty of a creature beginning in time but enduring through all eternity, an immortal being dependent for its existence on an act of physical generation, yet itself always and entirely unphysical and independent of the body which results from the generation. These are objections insuperable to the reason. But there is too the difficulty that this soul inherits a past for which it is in no way responsible, or is burdened with mastering propensities imposed on it not by its own act, and is yet responsible for its future which is treated as if it were in no way determined by that often deplorable inheritance….or that unfair creation, and were entirely of its own making. We are made helplessly what we are and are yet responsible for what we are,–or at least for what we shall be hereafter, which is inevitably determined to a large extent by what we are originally. And we have only this one chance. Plato and the Hottentot, the fortunate child of saints or Rishis and the born and trained criminal plunged from beginning to end in the lowest fetid corruption of a great modern city have equally to create by the action or belief of this one unequal life all their eternal future. This is a paradox which offends both the soul and the reason, the ethical sense and the spiritual intuition.”
Once we accept the idea of an eternal soul, it is essentially incumbent on us to recognize its past as well as its future. It is one thing to believe that life has no ultimate significance or future, and that the single birth is purely a chance of material creation, or an event in the All-Soul’s development, thus making the life ephemeral and transitory. It is quite another to start from a creation out of material forces at the time of birth, and then build onto it an eternity of future result.
Essentially, if there is a recognition of a future, there must be concurrently a recognition of a past, and this brings in a process and a mechanism which provides the underpinning for the theory of rebirth and karma.