The premise underlying Legion Theory is that the features of a broken system tell us something about the intact system.
The ‘broken system’ in Multiple Personality Disorder (MPD), or Dissociative Identity Disorder (DID) as it is now known, is one in which several unintegrated consciousness give the appearance of several people inhabiting a single body.
If our premise is correct, then the intact mental system of a person comprises multiple consciousnesses acting in an integrated way to give the appearance of a single unified system. But is it reasonable from what we know about the human brain? We argue it is because DID is not the only situation where systems of the human brain, which appear to be unitary, break down into separate parallel systems. If you follow the links on the right you will learn about three of these.