Vico himself started from a kind of scepticism, a scepticism as regards the prejudices of scholars and nations generally about the character and facts of antiquity: and in combating these prejudices he drew up a series of principles or "aphorisms," inspired apparently by Bacon's "idola," to which they present an analogy in the field of historical research. Vico puts the student on his guard first against the "magnificent opinions" which have been held up to his own day "concerning the most remote and least known antiquity": a naïve illusion whose origin he traces to the fact that man when in a state of entire ignorance erects himself into a rule for the universe. Here is the closest analogy with Bacon: for this statement is precisely like the class of "_idola tribus,_" in which thought makes itself the rule of things "on the analogy of man, not of the universe" (_ex analogia hominis, non ex analogia universi_). On the same observation is founded the remark that "rumour grows in its course," _fama crescit eundo,_ and Tacitus's _omne ignotum pro magnifico est,_ everything unknown is taken for something great. Hence arises the habit of interpreting ancient customs in the expectation of finding them similar or superior to those of modern civilised life. Thus Cicero admired the humanity of the early Romans in calling enemies in war "guests": not realising that the fact was precisely the opposite of this, and that guests were _hostes,_ strangers and enemies. In the same way Seneca, by way of proving the duty of kindness to slaves, recalled that masters were anciently called "fathers of the family"; as if _"patres familias"_ might not have been the very reverse of kind not only to slaves and servants but to their own children, regarded as on the level of slaves. The same prejudice led Grotius, in his desire to show the gentleness of the ancient Germans, to collect a great number of barbaric laws in which homicide was punished by a fine of a few pence: which is on the contrary really a proof of the cheapness of the blood of poor rustic vassals, who are precisely the "_homines_" mentioned by these laws. In the second place, he warns us not to trust to the "conceit of nations," all of which, Greek or barbarian, Chaldean, Scythian, Egyptian, or Chinese, claimed, as Diodorus Siculus observes, to have founded humanity, discovered the amenities of life, and preserved their memory intact from the beginning of the world. Each of them, having for several thousand years had no communication with the others which might have led to the sharing of ideas, resembled in the obscurity of its chronology a man who sleeping in a very small chamber is misled by the darkness into believing it much too large ever to touch it with his hand. He who accepts these dreamer's boasts for certain knowledge finds himself in the difficulty of having to choose between the various memories of various nations, all of which with equal justification claim to be original.