It is not pure quackery, you can make measurements on anything and use it for anything. The fact that it is not biologically "real" is a different thing. I can

It is not pure quackery, you can make measurements on anything and use it for anything. The fact that it is not biologically "real" is a different thing. I can make up a model for the human mind called there carboat model. It splits everyone up on a spectrum on how much they like boats and cars. Now I can use that model to make statistical assumptions about the people I measured. It bet the assumptions will have high accuracy on boat and car related matters.