Full Idea
The powerless in society are not usually taken to be trustworthy witnesses even when it comes to providing information about their own lives.
Gist of Idea
Powerless people are assumed to be unreliable, even about their own lives
Source
Martin Kusch (Knowledge by Agreement [2002], Ch. 5)
Book Reference
Kusch,Martin: 'Knowledge by Agreement' [OUP 2004], p.52
A Reaction
This is where epistemology shades off into politics and the writings of Foucault.