She refers to a book called Paradoxical Strategies in Psychotherapy (1986) by Leon Seltzer, which I wasn't able to track down, but the title led me to another one called Paradoxical Psychotherapy (1982) by Gerald R. Weeks & Luciano L'Abate, in which I was surprised to read:
The passage quoted is from Marcuse's Reason and Revolution:THE DIALECTICS OF CHANGE AND PARADOXICAL THERAPY
There is a philosophical link between paradoxical therapy and dialectics in that they view change similarly. Change is the essence of dialectics. Unfortunately, many readers may believe reference is being made to the famous triad of thesis, antithesis, and synthesis. Hegel was in fact opposed to the use of these simplistic terms; they misrepresent his philosophy because of their static and mechanical quality. To understand Hegel's theory of change, dialectics must be examined as the study of being. Marcuse succinctly summarized Hegel's ontology:
To know what a thing really is, we have to get beyond its immediately given state (S is S) and follow out the process in which it turns into something other than itself (P). In the process of becoming P, however, S still remains S. Its reality is the entire dynamic of its turning into something else and unifying itself with its "other." The dialectical pattern represents, and is thus "the truth of," a world permeated by negativity, a world in which everything is something other than it really is, and in which opposition and contradiction constitute the laws of progress.