Book 4
7.4
Similarly he recommended them to make themselves familiar with astronomy, but only so far as to be able to find the time of night, month and year, in order to use reliable evidence when planning a journey by land or sea, or setting the watch, and in all other affairs that are done in the night or month or year, by distinguishing the times and seasons aforesaid. This knowledge, again, was easily to be had from night hunters and pilots and others who made it their business to know such things.
7.5
But he strongly deprecated studying astronomy so far as to include the knowledge of bodies revolving in different courses, and of planets and comets, and wearing oneself out with the calculation of their distance from the earth, their periods of revolution and the causes of these. Of such researches, again he said that he could not see what useful purpose they served. He had indeed attended lectures on these subjects too; but these again, he said, were enough to occupy a lifetime to the complete exclusion of many useful studies.
7.6
In general, with regard to the phenomena of the heavens, he deprecated curiosity to learn how the deity contrives them: he held that their secrets could not be discovered by man, and believed that any attempt to search out what the gods had not chosen to reveal must be displeasing to them. He said that he who meddles with these matters runs the risk of losing his sanity as completely as Anaxagoras, who took an insane pride in his explanation of the divine machinery.
