Let us begin with what the texts actually say — and what they do not say.
Radha does not appear by name in the Bhagavata Purana. She is present — unmistakably, as the one Gopi to whom Krishna grants exclusive attention, the one who is taken apart from the dance, the one whose separation produces the Viraha — but she is not named. The name Radha appears first in the Brahma Vaivarta Purana and is developed extensively by Jayadeva in the 12th century Gita Govinda, by the Alvar saints of South India, and in the Chaitanya tradition of Bengal.
This is significant. The Bhagavata Purana — perhaps the most philosophically complete of the Puranas — presents the Radha-principle without reducing it to a biographical relationship. What it presents is this:
Among the Gopis — the cowherd women of Vrindavan — one is distinct. She has left her husband, her duties, her social position, everything that defines her place in the world, to follow the sound of Krishna's flute. Not out of romantic infatuation. Out of a love that the Bhagavata calls Parama Prema — supreme love, the love that has consumed every other attachment.
The tenth chapter of the Bhagavata Purana is entirely devoted to the Vrindavan Lila — the cosmic play. And the theological point is precise: Krishna does not love the Gopis because of anything they offer him. He does not love them for their beauty, their devotion, or their sacrifice. He loves them because love, in its pure form, requires no reason and no return.
The Bhagavata's radical theological claim: the highest religious state is not fear of God, not respect for God, not even devotion to God in the conventional sense. It is Prema — love for God that has completely dissolved the lover's separate existence. The Gopis do not pray to Krishna. They do not perform rituals for Krishna. They simply love him — with a completeness that the text describes as more spiritually advanced than the meditation of the greatest sages. Because meditation maintains the meditator. Prema dissolves the one who loves into what is loved. And in that dissolution, the Bhagavata says, the highest recognition occurs.
The Brahma Samhita — a Vaishnava text attributed to Brahma himself and quoted extensively by Chaitanya Mahaprabhu — presents the metaphysics explicitly. Krishna is described as Sac-Cid-Ananda Vigraha — the form of eternal being, consciousness, and bliss. Radha is his Hladini Shakti — his bliss-power, the aspect of his own nature that is the capacity for love, for delight, for the experience of beauty.
This is not a love story between two beings. It is the description of a cosmological principle: ultimate Consciousness contains within itself the capacity for bliss, for love, for the experience of beauty — and this capacity is not other than Consciousness, yet it has its own principle, its own expression, its own name. Radha is not someone Krishna loves. Radha is the bliss of Krishna — his own delight taking form, his own love recognising itself.