Matsya Purana — Cosmography of Jambūdvīpa: Varṣas
अचिन्त्याः खलु ये भावास् तांस्तु तर्केण साधयेत् प्रकृतिभ्यः परं यच्च तदचिन्त्यस्य लक्षणम् //
acintyāḥ khalu ye bhāvās tāṃstu tarkeṇa sādhayet prakṛtibhyaḥ paraṃ yacca tadacintyasya lakṣaṇam //
Truly, those realities that are inconceivable (acintya) are not to be established by mere reasoning. Whatever lies beyond all prakṛtis—beyond material nature—that is the defining mark of the Inconceivable.
It implies that the ultimate principle behind creation and dissolution is beyond prakṛti and therefore cannot be fully grasped through logic alone; Pralaya ultimately points to an acintya (inconceivable) reality transcending material nature.
It cautions rulers and householders not to reduce dharma to clever argumentation; right conduct should be grounded in śāstra, tradition, and disciplined insight, recognizing that the highest truth surpasses purely rational calculation.
No direct Vāstu or ritual rule is stated; the takeaway is methodological: sacred prescriptions (including temple-building and rites) ultimately rest on śāstric authority and a reality beyond prakṛti, not on reasoning alone.