Psychology is one of the most recent sciences to issue from the mother-tree of philosophy. One of the greatest challenges is that of formulating theories and methodologies that move the field toward theoretical structures that are not only sufficient to explain and predict phenomena but, in some vital sense, necessary for those purposes. Mathematical modeling is perhaps the most promising general strategy, but even under that aegis, the physical sciences have labored toward that end. The present chapter begins by outlining the roots of our approach in 19th century physics, physiology, and psychology. Then, we witness the renaissance of goals in the 1960s, which were envisioned but not usually realizable in 19th century science and methodology. It could be contended that it is impossible to know the full story of what can be learned through scientific method in the absence of what cannot be known. This precept brings us into the slough of model mimicry, wherein even diametrically opposed physical or psychological concepts can be mathematically equivalent within specified observational theatres! Discussion of examples from close to half a century of research illustrate what we conceive of as unfortunate missteps from the psychological literature as well as what has been learned through careful application of the attendant principles. We conclude with a statement concerning ongoing expansion of our body of approaches and what we might expect in the future.