There was, in fact, no spirit left for a Lucretian polemic against false beliefs. Everything in the nature of a searching criticism of life was menaced by the autocracy; Nero decreeing that no man should philosophize at Rome, [845] after slaying or banishing a series of philosophers; [846] Domitian crucifying the very scribes who copied the work of Hermogenes of Tarsus, in which he was obliquely criticized. [847] When men in the mass crouched before such tyranny, helplessly beholding emperor after emperor overtaken by the madness that accrues to absolute power, they were disabled for any disinterested warfare on behalf of truth. All serious impeachment of religion proceeds upon an ethical motive; and in imperial Rome there was no room for any nobility of ethic save such as upbore the Stoics in their austere pursuit of self-control, in a world too full of evil to be delighted in. Thus it came about that the Cæsars, who would doubtless have protected their co-operating priesthoods from any serious attack on the official religion, [848] had practically no occasion to do so. Lucian's jests were cast at the Gods of Greece, not at those of the Roman official cults; hence his immunity. What the Cæsars were concerned to do was rather to menace any alien religion that seemed to undermine the solidarity of the State; and of such religions, first the Jewish, and later the Christian, were obvious examples. Thus we have it that Tiberius "put down foreign religions" (externas ceremonias), in particular the Egyptian and Judaic rites; pulling down the temple of Isis, crucifying her priests, expelling from Rome all Jews and proselytes, and forcing the Jewish youth to undergo military service in unhealthy climates. [849] Even the astrologers, in whose lore he believed, he expelled until they promised to renounce their art--a precedent partly set up by Augustus, [850] and followed with varying severity by all the emperors, pagan and Christian alike. And still the old Italian religion waned, as it must. On the one hand, the Italic population was almost wholly replaced or diluted by alien stocks, slave or free, with alien cults and customs; on the other, the utter insincerity of the official cults, punctiliously conserved by well-paid, unbelieving priests, invited indifference. In the nature of things, an unchanging creed is moribund; life means adaptation to change; and it was only the alien cults that in Rome adapted themselves to the psychic mutation. Among the educated, who had read their Lucretius, the spectacle of the innumerable cults of the empire conduced either to entire but tacit unbelief, or to a species of vaguely rationalistic [851] yet sentimental monotheism, in which Reason sometimes figured as universal Deity. [852] Among the uneducated the progression was constant towards one or other of the emotional and ritualistic oriental faiths, so much better adapted to their down-trodden life. § 4