Ajivika thinkers understood the round of birth and rebirth as real, yet governed entirely by an inexorable determinism. The soul, or jīva, was seen as moving through saṁsāra along a course fixed in advance by niyati, an impersonal principle of fate or cosmic determinism. This meant that the pattern of lives, the sequence of experiences, and even the duration of the journey were all predetermined. The cycle was not random, but it was also not responsive to moral striving in the way Buddhists and Jains proposed. Rather than a field in which ethical choices reshape destiny, existence appeared as a script already written from the beginning of time.

Within this vision, karma did not function as a moral law capable of redirecting the future. Actions, whether virtuous or harmful, did not alter the timing, quality, or direction of rebirths. No practice—ethical discipline, meditation, or asceticism—could hasten or delay the unfolding of the cycle. The Ajivika path, therefore, did not aim to change fate but to recognize that all beings are carried along by it. Spiritual effort did not serve as a lever to move the cosmos; at most, it could be a way of aligning understanding with the inevitability of what must occur.

The cycle of rebirth was also held to be finite, though vast, rather than endless. Each soul was destined to pass through a fixed number of existences, a predetermined series of life-forms and states, before the journey was complete. This process was often likened to a ball of string that must fully unwind: once the last turn is released, the motion ceases of its own accord. Liberation, or cessation, thus arrived not as a reward for effort but as the natural terminus of an already allotted sequence. When the full measure of births had been exhausted, release came automatically, without any final act of will or realization to trigger it.

From this standpoint, the cycle of birth and rebirth became a kind of cosmic mechanism, steady and unalterable. Where other traditions emphasized moral responsibility and transformative practice, Ajivika teaching highlighted inevitability and endurance. Every being was destined, sooner or later, to reach purification and freedom, yet only when the predetermined course had fully run. The religious life, in such a framework, was less about engineering a different future and more about contemplating a universe in which everything that happens could never have been otherwise.