I think the quote states that it is important to acknowledge what type of knowledge (fact or fiction) the claim is, similar to acknowledging bias. However, if it is difficult to judge whether or not it is fact or fiction, then the value of the source is lost.
Does the value of knowledge change between AoK’s? , When is the line between fact and fiction blurred? , When is it not blurred? , Does the quote prefer fact? or fiction?
I agree that the value of knowledge changes between AoK’s, because each AoK serves a different purpose. The Arts are effective in creating a different thought process and stimulating thinking, whereas the Natural Sciences help to describe the realities of the world. They help people to come to different realisations about knowledge.
Imagination contributes to the blurring of the line between fact and fiction. This is because the imaginer often bases their imagination of facts to create fiction. Although this may help to increase the amount of information, according to the assumptions of the quote, it will lead to decreased value of the knowledge.