A Negative Hallucination is an idea that was first put forward by Sigmund Freud in 1890. He used the term to describe how a hypnotised person could be led to be unable to see a person or thing that was right in front of them once out of the hypnotised state, creating a gap in their reality. Sadly, this gap in reality seems endemic in the minds of many in the world, whether from lack of access to facts or from wilful ignorance. The result is the same regardless: a world where many oppressed peoples' reality is edited out of the conversation.