This latter tendency was hypercritical rather than critical, its end being the destruction of history in general: and since historical scepticism was very apt to assume the character of a paradox adapted to the needs of elegant society and the wits, its influence on the progress of research was very small, or at most it succeeded in producing strong reactions, one of which is represented by Vico, in favour of tradition and authority. It is on the other hand only proper to observe the failings of the first seriously scientific efforts of philologists and antiquaries. They rehabilitated witnesses, laid bare falsifications, reconstructed lists of rulers and magistrates, connected chronology and contradicted certain legends: but, whether owing to the tendencies of thought usual among pure scholars and philologists or because of the general atmosphere of their century's culture, they neither had nor conveyed a feeling for the antique and the primitive. Strong in detail, they were weak in essentials. When one of the most brilliant grasped, for instance, the importance of ballad-literature as a means of transmitting history at a period when the use of writing was unknown or uncommon, he did not receive from this observation and others like it such a shock as might stimulate him to recast from top to bottom his intuition and conception of primitive life, as was the case with Vico, who almost in a flash grasped the philosophical form of certitude and the two periods of mental and social life corresponding to it in actual history: the periods of obscurity and of legend.
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.
By the side of national conceit Vico placed the "conceit of the learned," who desire their own knowledge to be as old as the world, and consequently delight in fancying an inaccessible esoteric wisdom among the ancients, coinciding miraculously with the opinions professed by each one of themselves, which they dress in the garb of antiquity in order to enforce their acceptance. Such was the mistake not only of Plato, especially in the researches of the Cratylus, but of all historians, ancient and modern: Vico himself had fallen into it, and was therefore able to study it closely in his own case, when in the De antiquissima he believed himself to have found in the etymologies of Latin words the proof of an Italian metaphysic exactly agreeing with his own doctrines of the conversion of the veruni with the factum and of metaphysical points.
From these three prejudices, especially from the conceit of the learned, follows the fourth, here called that of the "sources" or "channels of culture," ironically called by Vico the theory of "scholastic succession among nations." Upon this theory Zoroaster for instance instructed Berosus for Chaldaea, Berosus in his turn Mercurius Trimegistus for Egypt, Mercurius taught Atlas the Ethiopian lawgiver, Atlas Orpheus the Thracian missionary, and finally Orpheus established his school in Greece. Long journeys these, and easy forsooth to those primitive nations which, scarcely out of the state of savagery, lived perched on mountains in almost inaccessible situations, unknown even to their neighbours! And these long journeys were undertaken with the object of spreading discoveries, which any nation could make for itself. If, when nations came to know each other through wars and treaties, they were found to agree, that was because they all contained some motive of truth and sprang from the same needs of man. Was it necessary to suppose the Athenian or Mosaic law to have affected that of the Romans, as did these "comparers" or delivers of laws, in order to explain the origin of the right recognised in Palestine, Athens and Rome to kill the thief by night? Was it necessary for Pythagoras to travel spreading the doctrine of the transmigration of souls, which we find as far afield as India?
There remained the prejudice of considering the ancient historians as best informed about primitive times: whereas in the history of origins they knew as little as, or less than, ourselves. As for Greek history, Vico found, or rather imagined that he found, in Thucydides, a confession that the Greeks up to the generation preceding that historian knew nothing of their own antiquity: and he also observed that it was only in the time of Xenophon that Greek historians began to have any precise information upon Persian affairs. Roman historians commonly began with the foundation of Rome: but the beginning of Rome was certainly not the beginning of the world. Rome was a new city founded in the midst of a large number of small and more ancient peoples in Latium: and even in the case of Rome Livy refuses to guarantee the truth of the facts of the earlier centuries of its history up to the Punic wars, which he is in a position to describe more accurately. He even confesses frankly that he does not know at what point Hannibal made his great and memorable entry into Italy, whether by the Cottian Alps or the Apennines. So well informed were the ancient historians!
Owing to these and similar sceptical principles, the whole of Greek history to the time of Herodotus and of Roman down to the second Punic war seemed to Vico quite uncertain, an unclaimed territory, so to speak, where one might enter and take possession by squatter's right. He entered armed with positive principles directly issuing from the negative ones we have enumerated. For if Vico denied the credibility of historians distant in time from the facts they described, if he discounted national pride, if he laid bare the illusions and charlatanism of the learned, he nevertheless did not rest content with this work of destruction. In place of the old untrustworthy method he had banished, he endeavoured to supply a new, of better qualities and greater tenacity; a system of methods by which it was possible to acquire new historical documents and also to improve the study of those already known. No advance in historical knowledge is in fact ever made except by thus turning from the received narrative to the document underlying it, which alone has the power of confirming, correcting and enriching the narrative.
The first of Vico's contributions to historical method, the first source for the knowledge of the earliest civilisations which he exposed, is the etymology of language. The usual methods of this study in his time were purely arbitrary: it proceeded by considering the sound of each syllable or letter and looking for other superficial resemblances, and inferring from these facts the derivation of a word from this or that language, Latin, Greek or Hebrew. But etymology becomes a fruitful study only when it is remembered that language is the best evidence for the ancient life of a people, the life lived by them while the language was in the making: and when the student accordingly never ceases to explain language by customs and customs by language. Thus the etymology of abstract words leads us into the heart of a purely rustic society; for intellegere, to understand, for example, recalls legere, to collect the produce of the fields (hence legumina, vegetables); disserere, to discuss, refers to scattering seed; and the majority of words for inanimate things reveal relations with the human body and its members, and the sensations and passions of man; thus "mouth" means any aperture, "lip" the edge of a pot, "forehead" and "back" are used for before and behind; and so on. Vico aimed at one science of etymology common to all native languages, composed of monosyllabic, and largely onomatopoeic roots: another of foreign loan-words, introduced after nations became mutually acquainted: a third, of universal application, for the science of international law, from which it should appear how the same men, facts or objects, looked at from the different points of view of different nations, received different names; and finally a dictionary of mental words, common to all nations, which should explain the uniform ideas of substances and the different modifications of them in national thought concerning the human needs and utilities common to all, according to the differences of their situation, climate, character and customs, and should thus narrate the origins of the various vocal languages, all converging in an ideal common language.
The second source revealed by Vico is the interpretation of myths or fables, which agreeably to his doctrine were not allegories, fictions or impostures, but the science of primitive man. In the Diritto universale Vico distinguished four different and successive characters of the gods. At first they represented natural facts, Jupiter the sky, Diana the flowing water, Dis or Pluto the lower earth, Neptune the sea, and so on; secondly, natural human affairs, for instance, Vulcan fire, Ceres corn, Saturn the seed; thirdly, social facts; and finally they rose to heaven and were translated to the stars, and terrestrial and human things were distinguished from divine. But in the two Scienze Nuove he emphasised almost exclusively the third or social meaning, which became in his eyes the original; since, he appears to have thought, the earliest nations were too much intent upon themselves, too much immersed in their hard and difficult life, to speculate in abstraction from social matters. Hence he found reflected in mythology the institutions, inventions, social cleavages, class-struggles, travels and warfare of primitive nations. Even in considerably advanced periods Vico was hostile to naturalistic or philosophical explanations. The saying "know thyself" attributed to the ancient sage seemed to him merely a piece of advice to the Athenian democracy, to know its own strength, later transferred to a metaphysical and moral sense. Beside this principle of social interpretation he established another of great importance: namely, that indecent meanings were inserted in myths at a late and corrupt period when men interpreted early customs in the light of their own, or tried to justify their own lusts by fancying that the gods had set them the example. Hence arose the adulterous Jupiter, Juno as the implacable enemy of Hercules' virtue, the chaste Diana soliciting the embraces of the sleeping Endymion, Apollo persecuting modest maidens even to their death, Mars, not content with committing adultery with Venus by land, but pursuing her even into the sea, and, worst of all, the love of Jupiter for Ganymede and of Jupiter again, transformed into a swan, for Leda. Such representations can only result in unrestrained vice, as happened in the case of the young Chaereas in Terence's comedy. But in their original shape and meaning all myths were serious and austere, worthy of the founders of nations. The pursuit of Daphne by Apollo for instance referred to the magicians or diviners who arranged weddings and followed women through the woods where they were still liable to promiscuous ravishing; Venus, covering her nakedness with the cestus, was a modest symbol of solemn matrimony; the heroes, sons of Jupiter, were not the offspring of adultery, but born of permanent and solemn marriages celebrated according to the will of Jupiter as revealed by the diviners. To the pure all things are pure, and impure to the impure: the forests and mountain-tops could never beget the fancies of the closet and the brothel.
Beside these two rich sources, language and mythology, Vico names and employs a third, which he calls the "great fragments of the ancient world," that is to say, the memories preserved by historians and poets, such as the Egyptian tradition of the three ages of gods, heroes and men; the language of the gods mentioned in Homer; the thirty thousand names of the gods collected by Varro and referring to a like number of needs in the natural, moral, economic and civil life of the earliest times; the grove of Romulus, which Livy calls "the ancient plan of founding cities," and a few other golden sayings of ancient historians. Till now these fragments had been useless for the purposes of science, lying as they did in dirt, confusion and incompleteness: but when cleaned, restored and fitted together they conveyed valuable information. Nor did he overlook the monuments of architecture and sculpture, though the use he made of them was slight, and he saw that they were in the long run of little practical value. He declared that as for the historic period the most certain documents are the public coins, so for the legendary and obscure period their place is taken by "certain traces remaining in marble," as proofs of ancient customs, like the Egyptian pyramids with their hieroglyphic inscriptions and other fragments of the ancient world found in every region and bearing similar pictographic characters. It is also worthy of remark that he gives examples of arguments founded on technical observations and leading to conclusions in the sphere of prehistoric archaeology: as for instance when he says that one early period of human life is distinguished by the eating of roasted flesh, the simplest and least elaborate kind of food, because it requires nothing except the fire: a later period by boiled flesh, which also requires water, caldron and tripod.