The quality of Darkness rests on that of Ignorance. The quality of Goodness, again, rests on that of Darkness. Darkness which is unmanifest overspreads itself on Knowledge, and creates the phenomena of Intelligence and Consciousness has been described as the seed of individual Souls. That, again, which is the seed of such knowledge is called the Jiya (or Individual Soul). On account of acts and the virtue of time, the Soul goes through birth and repeated rounds of re-birth.
रजस्तमसि पर्यस्तं सत्त्वं च रजसि स्थितम्। ज्ञानाधिष्ठानमव्यक्तं बुद्ध्यहङ्कारलक्षणम्॥ तद् बीजं देहिनामाहुस्तद् बीजं जीवसंज्ञितम्। कर्मणा कालयुक्तेन संसारपरिवर्तनम्॥