The Buddha rejected the first view in several texts such as the Kalama sutta, arguing that a claim to scriptural authority ("sadda") was not a source of knowledge, as was claimed by the later Hindu Mimamsa school. The Buddha also seems to have criticized those who used reason ("takka"). According to Jayatilleke, in the Pali Nikayas, this term refers "primarily to denote the reasoning that was employed to construct and defend metaphysical theories and perhaps meant the reasoning of sophists and dialecticians only in a secondary sense". The Buddha rejected metaphysical speculations, and put aside certain questions which he named the unanswerables ("avyakatas"), including questions about the soul and if the universe is eternal or not.