Even if historians find the evidence solid, records like this are usually too numerous not to require sampling, and drawing a truly random sample of historical records is much more complex than when doing survey research. Handbooks of statistics do not always reflect this fact. Nobody would think of undertaking a quantitative study nowadays without a computer (although desk calculators are quite adequate for some projects), and this raises a further difficulty insofar as historical records usually vary so much in terminology that they have to be encoded for computer use. Coding conventions are themselves interpretations, and few quantitative historians have never had occasion to curse themselves for premature or inconsistent coding. There is no foolproof remedy against this, but providing a database and a copy of coding conventions has become the recommended practice to enable other historians to evaluate the work.
Handbooks of historical method at the end of the 19th century assured students that if they mastered the interpretation of written documents, they would have done everything required to be a historian. “No documents, no history,” one said. In this century the notion of a document has been enormously expanded so that any artifact surviving from the past can serve as the answer to some historian’s question. Aerial photography, for example, can reveal settlement patterns long since buried. Napoleon’s hair can be examined to see whether he died a natural death or was poisoned; analysis of Newton’s hair showed that he was an alchemist. The architecture along Vienna’s Ringstrasse can be construed as revealing the ambitions of the liberal bourgeoisie. The history of sexuality cannot be written without the history of clothing—even the nudes in classical paintings pose in postures influenced by the clothes they are not wearing. Indeed, the ordinary things of all kinds to be found in a folk museum are one of the best sources for the everyday life of people in the past.
Artifacts do not usually tell their own stories. When written documents can be juxtaposed to them, the results are more illuminating than either can be by themselves. Unfortunately, virtually the whole training of historians is devoted to reading written texts, so that skill is hypertrophied, while the ability to interpret material objects is underdeveloped. When historians can, for example, accurately describe how the machines of the early Industrial Revolution really worked, they will have met this challenge—which is, of course, a challenge to know almost everything.
Historians today benefit from much more integrated and comprehensive archival and library systems than existed in previous centuries. The state papers of the United States, for example, were not in usable condition in 1933. Thanks again in part to the efforts of WPA workers, great improvements were made in cataloguing and preservation; now a new archive building in suburban Maryland has been built to cope with the tide of documents produced by the U.S. government. The same step has been taken in Britain, and both Britain and France have new national libraries. Less spectacular, but invaluable to many historians, are the local historical societies, county record offices, and the like, which have been established in many countries. These have allowed the collection and preservation of documents that originated in a great variety of places—churches, courts, city and county governments, legal offices, and collections of letters. One of the remarkable developments of the period since the dissolution of the Soviet Union in 1991 has been the widespread sale of public and private records to Western collectors. Libraries such as Yale or the Hoover Institution (at Stanford University) are now in many ways better places to study the Soviet period than any in Russia, and if one can fault the failure of the Russian government to pay its librarians and the wild capitalism of the new Russia for dispersing these treasures, at least they will be safely preserved. They have already answered many questions about how the Soviet Union was run.
The proliferation of libraries and archives illustrates what is in some ways the greatest difficulty with regard to modern sources—there are too many of them. Most discussions of historiography focus on how historians tease out the exiguous meanings of documents when they are very scarce. The problem facing the historian of the 19th century and even more of the 20th is how to cope with the vast array sources open to him. Computers and the Internet have vastly enhanced the speed with which printed sources can be searched—titles of all the books in all the major Western libraries are online—but the historian must know a great many descriptors to do a reasonable subject search. Furthermore, the Internet has brought as much misinformation as information, if not more.
In the 16th and 17th centuries it was taken for granted that the historian would work alone and would usually own many of his books. The library of Göttingen, the pride of 18th-century Germany, would be small even for a new university or a modest liberal-arts college today. Great reputations could be made in the 19th century for the discovery of a new archive (such as Ranke’s discovery of the Venetian relazioni). Nothing like this could possibly happen today, yet such is the conservatism of the historical profession that the model is still the single scholar exhausting the archives. The archives for modern history are inexhaustible, and collaboratively written works, already becoming somewhat common, will almost certainly have to become even more so if historians are to meet their traditional goals of comprehensive research. From explanation to interpretation
Until quite recently almost everybody who thought about historiography focused on the historian’s struggle with the sources. Philosophers were interested in the grounds they had for claiming to make true statements about the past. This directed their attention to the process of research; it was not unusual to say that after learning “what actually happened,” the historian then faced only the relatively unproblematic process of “writing up” his findings. This emphasis aptly captured the way that historical method is taught and the understanding of their craft (as they like to call it) that historians entertain. Nevertheless, no historian can rest content simply with establishing facts and setting them forth in chronological order. Histories, as opposed to annals and chronicles, must not only establish what happened but also explain why it happened and interpret the significance of the happening.
The slightest familiarity with historical writing shows that historians believe that they are explaining past events. Criticizing the explanations presented by other historians is an integral part of historical scholarship—sometimes carried to such tedious lengths that the actual narrative of events disappears under a tissue of scholastic sludge. However, it is unusual for historians to question what constitutes a historical explanation. A few abnormally reflective ones—and those few philosophers who have turned their attention to thinking about history—have demonstrated that this is not a simple task.
One philosophical school, logical positivism (also called logical empiricism), held that all other scholarly disciplines should offer explanations like those of physics, the most advanced (and mathematicized) science. The model of historical explanation was illustrated by the bursting of the radiator in an automobile. Explanation of this mishap went as follows: first, certain “boundary conditions” have to be specified—the radiator was made of iron and filled with water without antifreeze, and the car was left in the driveway when the temperature fell below freezing. The explanation consists in enumerating the relevant boundary conditions and then adducing the appropriate “covering” laws—in this case, that water expands as it freezes and the tensile strength of iron makes it too brittle to expand as much as the water does. These are, of course, laws of physics, not of history.