Oral history has exhibited massive changes since it is passed by the word of mouth from one generation to another, hence may be a subject to bias.
Historians do evaluate the validity and reliability of each source through content analysis. They must query the existence of the facts with relation to certain historical event. To establish the validity and reliability of the event, the historians have to make a clear comparison of two separate accounts of a similar event. The two accounts must show some relationship. Historians may also be at the verge of classifying the history with close reference to aspects of religion, culture or agriculture. Such classification does allow any historian to follow up closely on the relationship between any two frameworks, hence further illuminating the historical patterns (Breisach, pg. 67).
Henry Kissinger does define history as the past memory of different countries. In his book A World Restored, he makes clear explanation of the concept of history. He explains the history of Europe in 19th century, making clear views of Austria and England but showing clear ignorance of the people who suffer from the policies of the country. Kissinger notes that history is not a result of the determination of a man. He emphasizes on the fallibility of man rather than his strengths. He puts it that history is an act of an unsuccessful attempt after several trials to bring order in a confused area. Primarily, he stresses on the point that history is simply a repeated failure of men to bring to a control the events at stake and achieve stability. He demonstrates a very pessimistic perception about history, laying emphasis on conflicts that do arise without any avoidance mechanisms. He responds to his claims by quoting that the peace that was in existence in Europe prior to French Revolution had been maintained by several men. He also adds that the lower class workers in Asia, Africa, and England did experience intense violence, hunger