As regards Daniel's theories, he denied that speculation could be regarded as a source of knowledge, and, probably in accordance with this tenet, he maintained, in opposition to Anan, the principle that the Biblical laws must not be interpreted allegorically, nor explained contrary to the simple text (see below). He evinces little regard for science, as, for instance, when he asserts that it is forbidden to determine the beginning of the new moon by calculation, after the manner of the Rabbis, because such calculations are condemned like astrology, and the practise of them is threatened with severe punishment, according to Isaiah xlvii. 13–14. Yet Daniel himself, in his commentary to Leviticus xxvi., indulges in long reflections on the theodicy and on the suffering of the pious. His conception of the angels, also, is most extraordinary. He says that wherever "mal'akhim" (angels) are mentioned in the Bible, the designation does not refer to living, speaking beings who act as messengers, but to forces of nature, as fire, fog, winds, etc., by means of which God performs His works (compare Maimonides, "Moreh," ii. 6). This may be due to the influence of the Sadducees (who also denied the existence of angels; compare Acts xxiii. 8), in view of the fact that works circulated among the earlier Karaites named after Zadok and containing Sadducee opinions.