Circle of Necessity

The Circle of Necessity or Cycle of Necessity refers to the compulsory process of reincarnation that every spiritual individuality has to go through. H. P. Blavatskydescribes this as the Third Fundamental Proposition of The Secret Doctrine:

The fundamental identity of all Souls with the Universal Over-Soul, the latter being itself an aspect of the Unknown Root; and the obligatory pilgrimage for every Soul — a spark of the former — through the Cycle of Incarnation (or “Necessity”) in accordance with Cyclic and Karmic law, during the whole term. In other words, no purely spiritual Buddhi (divine Soul) can have an independent (conscious) existence before the spark which issued from the pure Essence of the Universal Sixth principle, — or the over-soul, — has (a) passed through every elemental form of the phenomenal world of that Manvantara, and (b) acquired individuality, first by natural impulse, and then by self-induced and self-devised efforts (checked by its Karma), thus ascending through all the degrees of intelligence, from the lowest to the highest Manas, from mineral and plant, up to the holiest archangel (Dhyani-Buddha). The pivotal doctrine of the Esoteric philosophy admits no privileges or special gifts in man, save those won by his own Ego through personal effort and merit throughout a long series of metempsychoses and reincarnations.