What is the whole "seth" phenomenon?

In the book Beyond the Quantum it talks about an entity who spoke through a woman by the name of Jane Roberts. Physicists who spoke with seth were amazed of the knowledge he had which far exceeded their own, and knew that Roberts didn't have as much information about reality as this seth entity. I find it very fascinating. Especially if there was a chance that this wasn't just part of jane roberts sub conscious or anything, and seth was a separate entity which roberts allowed to communicate through her.(accurate discription?) I would like to hear some opinions on this topic. Thanks.