Thanks for the replies. I have looked quite a bit at the compassion/method side of the Mahayana, which is where the "law of opposing states" is generally discussed, as in the HHDL quote.
My underlying question, however, is different. Does this same law also operate in insight meditation, or at least some kinds?
For example, one classical emptiness meditation juxtaposes the "object of negation", say the reified self, with the firm, reasoned conclusion that the self cannot exist that way (as reified, independent, etc) because if it does, then it must be either one with or not one with its parts, and further reasoning and observations show both to be impossible. So there are the opposing states. Eventually the reified self dissolves, leaving in its place a perception of emptiness of the self, that is, its lack of reified, independent nature.
Is it correct to say that the law of opposing states is working there too? It sure seems so, but I cannot find that in any teaching or commentary.
His Holiness The Dalai Lama says (Universe in a Single Atom, pp. 146-147) ...
Like other Buddhist thinkers before him, Dharmakirti invokes what could be called a “psychological law” in that he sees various psychological states, including the emotions, as a field of forces in which opposing families of mental states interact in a constant dynamic... This law whereby two opposing states cannot coexist without one undermining the other is the key premise in the Buddhist argument for the transformability of consciousness..."
I'd be grateful for pointers to books, papers and web sites discussing this "psychological law" in Buddhism, both traditional and modern. What are English terms used to translate this topic (to help me search for myself)?