Moreover, mystical speculations on the nature of Agni, so important a god in the eyes of a priesthood devoted to a fire-cult, on his many manifestations as individual fires on earth, and on his other aspects as atmospheric fire in lightning and as celestial fire in the sun--aspects which the Vedic poets are fond of alluding to in riddles--would suggest the idea that various deities are but different forms of a single divine being. This idea is found in more than one passage of the later hymns of the Rigveda. Thus the composer of a recent hymn (164) of the first book says: "The one being priests speak of in many ways; they call it Agni, Yama, Matariçvan." Similarly, a seer of the last book (x. 114) remarks: "Priests and poets with words make into many the bird (i.e. the sun) which is but one." Utterances like these show that by the end of the Rigvedic period the polytheism of the Rishis had received a monotheistic tinge. Occasionally we even find shadowed forth the pantheistic idea of a deity representing not only all the gods, but Nature as well. Thus the goddess Aditi is identified with all the deities, with men, with all that has been and shall be born, with air, and heaven (i. 89); and in a cosmogonic hymn (x. 121) the Creator is not only described as the one god above all gods, but is said [3] to embrace all things. This germ of pantheism developed through the later Vedic literature till it assumed its final shape in the Vedanta philosophy, still the most popular system of the Hindus. The practice of the poets, even in the older parts of the Rigveda, of invoking different gods as if each of them were paramount, gave rise to Professor Max Müller's theory of Henotheism or Kathenotheism, according to which the seers held "the belief in individual gods alternately regarded as the highest," and for the moment treated the god addressed as if he were an absolutely independent and supreme deity, alone present to the mind. In reality, however, the practice of the poets of the Rigveda hardly amounts to more than the exaggeration--to be found in the Homeric hymns also--with which a singer would naturally magnify the particular god whom he is invoking. For the Rishis well knew the exact position of each god in the Soma ritual, in which nearly every member of the pantheon found a place.