Contestability is a source evaluation skill which requires you to acknowledge that different historical interpretations can be supported by the surviving evidence.
Contestability is the idea that two separate sources can draw different conclusions about a historical person, concept or event.
Contestability most commonly occurs between two modern sources, typically academics, who have studied the surviving material in detail, but hold two different interpretations of the past.
The ability for different interpretations is often caused by a lack of surviving primary sources for anyone to know for certain which interpretation is most likely to be correct. On these occasions, the different interpretations are both considered valid until further evidence is found.
Two different historians could study the surviving archaeological and written evidence for the reign of the ancient Egyptian pharaoh Akhenaten and draw different conclusions about his reasons for abolishing traditional polytheistic religion: one historian could argue that Akhenaten was doing it from sincere religious motives, while another could argue that he did it for purely political reasons. Either argument can be supported by the remaining evidence and, therefore, Akhenaten's motives are contestable.
Just because two different sources have different opinions doesn’t automatically show contestability. Both sources need to be considered reliable sources of information in order to trust their interpretation. If you find that one opinion is from an unreliable source, then its interpretation is not considered a valid basis for contestability.
A university academic could say that the Egyptian pyramids were built by humans, while a conspiracy theory website could say that the pyramids were built by aliens. Just because they have different opinions doesn’t show contestability: in this example the website is far less reliable than an academic and, therefore, its interpretation can be discounted.
When you are reading and researching sources, look for any of the following:
If you notice any of the above, it could indicate that the topic you are investigating is contestable. On such occasions, take the time to record the names of the different sources and record how they understand the topic. It might also be worthwhile recording the evidence each source quotes to justify their interpretation.
Demonstrating contestability in your writing:
Sir Flinders Petrie believes that Akhenaten was a sincere seeker of religious truth (1894, 41), while Historian Redford argues that the pharaoh used religion as a mask for his ultimate aims to create a new dictatorial system under his direct control (1984, 233-5).
The conflicting first-hand accounts of the Battle of Borodino have led historians to draw different conclusions about who the true victor was. Russian historian Sokolov argues that Napoleon won, despite massive losses (Sokolov, 2005, 454-5), but Duffy believes that it was a draw, despite both sides claiming victory (1972, 217).