Every single one of us possess these biases, in endless different forms. Making it very hard for anyone to be completely objective, if it is even possible. So the historian has a great responsibility to use many different methods of researching to record events as objectively as possible. In order to do this the historian should always seek emotional distance from the events they are trying to record. The reason for this being what they are trying to record has been so influenced by human emotions, which will bring up the historians own emotions and views, this being exactly what the historian is always trying to avoid. It is so important for them to approach it with a, "cool-headed detachment," allowing them to have a much clearer view of what really happened. .
There is a series of questions that need to be carefully asked with meticulous scholarship when assessing the sources authenticity, sometimes known as external criticism. The aim is to discover weather the author, place and date are what they claim or appear to be. In the past there have been historical forgeries created for such things as to make money or other corrupt ideas. So it is important to ask, is there a hidden agenda? This is where palaeography and philology should be used to test the script, language and style, to discover if it matches with the period it claims to be. When studying secondary sources it is vital to research the author, to understand where the individual is coming from. What is their background? Do they have a more left or right wing prospective? What kind of lives have they lead? Why are they researching it? etc. The answers to these could uncover a witting or unwitting testimony in their work. A good historian will use many different secondly sources, of authors from a wide range of different backgrounds, to get a well rounded view. "The mastery of a variety of sources is one of the hallmarks of historical scholarship," (Tosh, J, 2010, p 104).