Matsya Purana — Characteristics of Dvāpara and Kali Yugas
आयुर्वेदविकल्पाश्च अङ्गानां ज्योतिषस्य च अर्थशास्त्रविकल्पाश्च हेतुशास्त्रविकल्पनम् //
āyurvedavikalpāśca aṅgānāṃ jyotiṣasya ca arthaśāstravikalpāśca hetuśāstravikalpanam //
And there are the various branches of Āyurveda, the subsidiary Vedic disciplines (Vedāṅgas), and Jyotiṣa (astral science); likewise, the various branches of Arthaśāstra (polity and statecraft) and the systematic formulations of Hetuśāstra (logic and reasoning).
This verse does not describe Pralaya directly; it catalogues branches of knowledge (medicine, Vedāṅgas, Jyotiṣa, polity, and logic), showing the Purana’s concern with preserving and transmitting learning across ages.
By naming Arthaśāstra and Hetuśāstra, the verse implies that rulers and householders should cultivate practical governance, ethical administration, and sound reasoning—skills central to dharma-based leadership and social order.
No explicit Vāstu/temple rule appears in this verse; its ritual significance lies in treating structured knowledge (śāstra) as worthy of preservation and gifting (vidyā-dāna), a valued religious merit in the Matsya Purana.