[1717] An unfixed phenomenon (aniyata dhamma) is a condition for a phenomenon fixed in rightness (sammattaniyata dhamma) by decisive-support condition (upanissaya-paccaya): object decisive-support (ārammaṇūpanissaya), proximity decisive-support (anantarūpanissaya), natural decisive-support (pakatūpanissaya).
Natural decisive-support: the preliminary work (parikamma) for the first path is a condition for the first path; the preliminary work for the fourth path is a condition for the fourth path, by decisive-support condition.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.