The scales of justice fallacy refers to the error of using a simple polarized scheme for deciding a complex issue: each piece of evidence about the question is individually categorized as supporting exactly one of the two opposing positions. This scheme distorts the conclusions that can be drawn from each piece of evidence, doesn't allow to take into account the dependencies between the pieces of evidence in the context of the issue, and biases perception of individual pieces of evidence, making the ones that fall into the same category seem to support each other, and ones falling in the opposite categories to seem to oppose each other. In reality, individual pieces of evidence may be separate factual claims, arrived at independently, with the issue depending on specific combinations of facts.

Blog posts

The Scales of Justice, the Notebook of Rationality by Eliezer Yudkowsky
Policy Tug-O-War by Robin Hanson

See also