Is the Attained Fruit of Hīnayāna Subject to Regression?

When a fourth-fruit Arhat returns to the secular world, they regress from the fourth fruit to the third fruit. After renouncing worldly life again and withdrawing from secular affairs, they once more attain the fourth-fruit Arhatship. If a fourth-fruit Arhat can regress, a third-fruit practitioner certainly can also regress. Meditative concentration can also disappear, and mental states can also regress. Even a second-fruit practitioner can regress back to the first fruit. A fourth-fruit Arhat, having eradicated attachments, can still regress and give rise to attachments again—let alone a third-fruit practitioner.

Specific examples in the Buddhist scriptures attest to this. Those who have not attained that level of fruition cannot comprehend it. Those in lower positions cannot see clearly into higher states, nor can they comment on them. To grasp the truth of the matter, one must experience it personally. It is like many people today who, clearly still at the stage of ordinary beings, spend their days debating the realm of Buddhahood, arguing until their faces turn red—all of it is armchair strategizing, utterly meaningless.