_B._ The mathematics and astronomy. But for that sublunary physics, which is commonly called natural philosophy, I have not read of any nation that studied it earlier than the Greeks, from whom it proceeded to the Romans. Yet both Greeks and Romans were more addicted to moral than to natural philosophy; in which kind we have their writings, but loosely and incoherently, written upon no other principles than their own passions and presumptions, without any respect to the laws of commonwealth, which are the ground and measure of all true morality. So that their books tend rather to teach men to censure than to obey the laws; which has been a great hindrance to the peace of the western world ever since. But they that seriously applied themselves to natural philosophy were but few, as Plato and Aristotle, whose works we have; and Epicurus whose doctrine we have in Lucretius. The writings of Philolaus and many other curious students being by fire or negligence now lost: though the doctrines of Philolaus concerning the motion of the earth have been revived by Copernicus, and explained and confirmed by Galileo now of late. _A._ But methinks the natural philosophy of Plato, and Aristotle, and the rest, should have been cultivated and made to flourish by their disciples. _B._ Whom do you mean, the successors of Plato, Epicurus, Aristotle, and the other first philosophers? It may be some of them may have been learned and worthy men. But not long after, and down to the time of our Saviour and his Apostles, they were for the most part a sort of needy, ignorant, impudent, cheating fellows, who by the profession of the doctrine of those first philosophers got their living. For at that time, the name of philosophy was so much in fashion and honour amongst great persons, that every rich man had a philosopher of one sect or another to be a schoolmaster to his children. And these were they that feigning Christianity, with their disputing and readiness of talking got themselves into Christian commons, and brought so many heresies into the primitive Church, every one retaining still a tang of what they had been used to teach. _A._ But those heresies were all condemned in the first Council of Nice. _B._ Yes. But the Arian heresy for a long time flourished no less than the Roman, and was upheld by divers Emperors, and never fully extinguished as long as there were Vandals in Christendom. Besides, there arose daily other sects, opposing their philosophy to the doctrine of the Councils concerning the divinity of our Saviour; as how many persons he was, how many natures he had. And thus it continued till the time of Charlemagne, when he and Pope Leo the third divided the power of the empire into temporal and spiritual. _A._ A very unequal division. _B._ Why? Which of them think you had the greater share? _A._ No doubt, the Emperor: for he only had the sword. _B._ When the swords are in the hands of men, whether had you rather command the men or the swords?