Panenmentalist possibilities are individual pure possibilities existing independently of any mind, actual reality, and possible-world conception. These possibilities are a priori accessible to our intellect and imagination. In this paper, I attempt to shed some panenmentalist light on the discovery of chemical branched chain reactions and its implications on biology and cancer research. I also examine the case of the Belousov–Zhabotinsky reaction which, at first, was believed to be impossible. Finally, I proceed to examine through a panenmentalist lens Szilard’s discovery (...) of the possibility of physical chain reactions and Mullis’s discovery of a polymerase chain reaction. All these major actual discoveries clearly depend on the discovery of the relevant panenmentalist possibilities and the ways in which they relate to one another. (shrink)