What is Knowable is Nature; while what is Unknowable is Soul. Both Nature and Soul are said to be unintelligent, stable, indestructible, unborn and eternal, according to the decision of the philosophers who know the spiritual science.
तथैव वेद्यमव्यक्तमवेद्यः पुरुषस्तथा। अज्ञावुभौ ध्रुवौ चैव अक्षयौ चाप्युभावपि॥ अजौ नित्यावुभौ प्राहुरध्यात्मगतिनिश्चयाः॥