 The bodhisattva then embarks upon the practices and disciplines, to be continued through countless lifetimes, that will finally result in fulfillment. It is said that vast aeons—“three great innumerable kalpas”—are required for the completion of a bodhisattva’s practices (the inconceivable stretches of time may be understood as expressing the depths of a being’s evil karma to be eradicated and the preciousness of enlightenment). The process of practice has been formulated in a scheme of ten stages, in which the most crucial is the stage of nonretrogression, the first (or in some formats, the seventh). While prior to reaching this stage, they will fall back into samsaric existence if they discontinue their practice, once they have attained nonretrogression through stilling their discriminative thought and seeing suchness, they will never regress but steadily advance in their practice to supreme awakening.