A healthy skepticism

In my current work assignment, I am able to listen to a wide variety of podcasts.  I recently started listening to the BBC History Magazine podcast and heard a line there that easily sums up my opinions toward most historical sources.  In the October 2007 episode, there was an interview with Laurence Rees.  He was talking about his experiences interviewing World War II veterans and survivors as part of a BBC Television production about the war (some of which is now online at WW2History.com) and the reception that he got for the interviews from other historians.  He said:

"Historians are skeptical of all sources -- everything, not just oral sources, but written sources as well."

He's not saying that historians think all sources are wrong, he's saying that historians are always willing to accept that the documentation could be incorrect.  Since we don't yet have time machines and can't go back to witness events first-hand, we have to rely on documentation.  But, how many of us have written checks in early January and wrote the previous year's number instead of the new year's number?  Even on the day of an event, when the person writing the document is physically present at the event and writing things down immediately, errors can and will be made.  Then when the events are researched later, the errors are copied and subsequently propagated to new research and eventually there are more references with the error than without.  As researchers, we have to keep a healthy dose of skepticism when we read documents and continually remind ourselves that there could be errors in what we are reading.  It is only through a complete analysis of all the source materials we collect that we can build a truly representative picture of the lives we are researching.