Max Duncker, The History of Antiquity, Vol. 5…
“ Not only are the good and evil spirits combined under one head, as is always the case in the Avesta, but the Gathas attempt to resolve the contrast of the beneficial and harmful sides of nature, of the good and evil spirits, into the reciprocal play of two fundamental forces; they identify the prosperity and destruction of nature with moral good and evil, and combine the one with truth, the other with falsehood. ”
