[From Bruce Abbott (2015.12.03.1040 EST)]
W. Ross Ashby’s book Design for a Brain (1952) is the source from which Bill Powers borrowed the concepts of “intrinsic variables” (Ashby called them “essential variables”) and reorganization. You can download the 1960 edition of this book from https://archive.org/details/designforbrainor00ashb for free in several formats, including PDF (scroll down the page to see options). Although Bill disagreed with Ashby on some points (he thought that Ashby advocated feed-forward over feedback control), the reader will find Ashby’s treatment of the problem illuminating. Ashby’s “homeostat,” described in the book, provides a concrete example of reorganization that was realized in an electro-mechanical device of Ashby’s invention.
Bruce