Māyā is at once a concept and a name reflecting that concept. Its root is mā, meaning the mother goddess and to measure out or create, and māyā is the transformation of the god's thought into the material form often represented mythologically by his wife—his particular goddess or śakti (see śakti), his creative energy—or as the all-encompassing Goddess (see Devī) as Mahādevī or Mahāśakti. It is the principle of māyā that can explain the movement from the intangible and indivisible Self that is Brahman (see Brahman) to the differentiated and tangible reality that is the world. Among some Buddhist (see Buddhism) schools māyā is the source of the “illusion” that we think of as the “real.” It should be noted that Queen Māyā or Mahāmāyā is the mother of Gautama Buddha (see Gautama Buddha), the vehicle of his incarnation and of his transformation to worldly form. Māyā is also Māyādevī, the personification of delusion. In the Bhāgavata Purāṇa (see Purāṇas), she is the girl who is exchanged for Kṛṣṇa (see Kṛṣṇa), thus the illusion of reality exchanged for divine reality.