  We find the source of all these applications of attraction in the questions that Mr. Newton posed at the end of his  Optics.[28] The disciples of this great man believed that his doubts might serve even as a basis for their hypotheses: but it must be admitted that some of these hypotheses are a bit forced and that there is a great difference in accuracy between the applications of attraction to celestial phenomena and the use one makes of it in the other effects just mentioned. Also this use of attraction is not as universally received by the same Newtonians, as the use of it when one is in fact explaining astronomical phenomena. (IP §391; emphasis  added)[29] 