A Unified Analysis of Innovative Scientific Practices: Nancy Nersessian's Conception of Model-Based Reasoning  

From a cognitive approach to science of Kuhnian tradition, various scientific practices omnipresent in scientific change have been investigated, understanding them as forms of model-based reasoning (MBR). I will analyse Nancy Nersessian´s conception of this type of scientific thinking. In particular, I will highlight that Phillip Johnson-Laird´s theory of mental models provided it with a framework for analyzing scientific practices just mentioned ina a unified way.

N. Nersessian proposed a unified conception of heuristic reasoning practices that have played a central role in the construction of new scientific concepts. She primarily referred to analogical procedures, visual representations, and thought experiments (1) (Nersessian N, 1992a; 1992b). She called the aformentioned conception, "the hypothesis of reasoning via ´mental modeling´" (Nersessian N, 2002). This perspective constitutes the "dynamic" dimension of the theory of conceptual change in science that Nersessian outlined, a dimension that refers to the processes through wich conceptual change occurs (Nersessian N, 1992a). 

   The hypothesis of reasoning via "mental modeling" focuses on the "cognitive basis", i.e., on the human cognitive capacities and limitations that facilitate and constrain the aforementioned reasoning practices. Thus, it asserts that the heuristic reasoning involved in conceptual change is based on mental modeling (Nersessian N, 1992a; 1999; 2008; 2009. Schwartz N, 2017). "One of my concerns in developing an account of conceptual change in science is to develop what Ronald Giere (1992) has called ´the cognitive foundations´ for such model-based reasoning, which, on my analysis, includes the use of analogical and visual models as well as thought experiments" (Nersessian N, 1992b, p. 292).

   Nersessian situated her analysis of model-based reasoning within the perspective of mental modeling in cognitive science. Specifically, her view followed the orientation of Phillip Johnson-Laird´s theory of mental models. "My analysis of model-based reasoning adopts only a ´minimalist´ hypothesis: that in certain problem-solving tasks humans reason by constructing a mental model of the situations, events and processes in WM that in dynamic cases can be manipulated through simulation" (Nersesessian N, 2002, p. 143). Johnson-Laird (1983) gave a general conception of mental models as structures created in working memory (WM) during processes of comprehension and reasoning. In this context, he maintained that mental models are created and manipulated, for example, when reasoning creatively.