The Nature of Evidence

Criminal detectives like Sherlock Holmes rely almost entirely on one type of evidence: those things which are directly linked to the case they are investigating...a splash of blood, a ransom note, hair from the victim found at the suspect's apartment, stolen goods in the trunk of the suspect's car, and so on.   Historians generally refer to these types of evidence as primary sources.   Unlike criminal detectives, who almost always lack enough evidence to build a convincing case, historians are typically confronted with too many facts.  As a result, one of the most difficult tasks an historian faces is deciding what to include and what to exclude when building his or her argument.

Almost any piece of evidence or any fact that is directly connected to the events, developments or people an historian is researching, whether it be a letter, a page from a diary, a speech, a photograph, a painting, a novel written at the time, a coin, a menu, or even a butterfly collection created by one of the people being studied, qualifies as a primary source.  The historian's task is to decide which of the many primary sources available can best be used to build a case for the thesis the historian is arguing.

An additional resource that the historian has that the detective does not, is a generally large existing literature on the subject.   Usually someone has already written something about whatever it is that you are interested in.  These writings are known in the history business as secondary sources.  Secondary sources are distinct from primary sources because they are not produced by the actors in the historical drama you are researching, but rather are produced by others, like yourself, who are writing about that historical drama, but after the fact.

Just as in the case of primary sources, you may find that you are confronted with too many secondary sources, or with a set of secondary sources that strongly disagree with one another.  Reading secondary sources productively takes practice.  If you are going to navigate your way through them and make good use of these works, you will need to spend some time thinking critically about what they say, how they say it and why they say it the way they do.

When it comes time to build your own case, you will need to use both primary and secondary sources.  Primary sources are the facts that should be the foundation of whatever you argue, while secondary sources are the larger conversation within which your own argument exists.  Too much reliance on one type of source is always a handicap, so be judicious in your use of each type.

Citing your sources properly in your papers is an essential skill that you need to develop this semester.   When you write, be sure to read up on how to cite your sources correctly by following the link in the previous sentence.

Last modified 05/26/00