ABSTRACT
The relationship of quality to quantity is a problem in psychoanalysis. Catastrophe theory was a first step in the direction of the nonlinear study of complex systems, in particular psychoanalysis. Catastrophe theory shows that quantitative changes can produce topologically distinct results and, hence, qualitative change. The problem of the relation of qualitative change to quantitative change lies at the intellectual heart of several psychoanalytic controversies. Until recently, no adequate conceptual tools were available to address how quantitative change results in changed qualities. The model of scientific discourse within which Freud developed his metapsychology excluded quality from its domain. The success of classical physics and most modern physical sciences rests on the use of mathematical formulations called differential equations. Differential equations describe how variables change with regard to one another. Isaac Newton invented differential equations to explore how objects moved under the force of gravity.
