[ CogSci Summaries home | UP | email ]

Nersessian, N. J. (1992). How do scientists think? Capturing the dynamics of conceptual change in science. In Giere, R. N. (ed.) Cognitive Models of Science. 5--22. University of Minnesota Press. Minneapolis, MN.

  author = 	 {Nersessian},
  title = 	 {How do scientists think? Capturing the
 dynamics of conceptual change in science},
  year = 	 {1998},
  OPTpages = 	 {5--22},

Author of the summary: Jim Davies, 2001, jim@jimdavies.org

The actual article is online at: [ PDF]

Cite this paper for:

By examining the practices of scientists and cognitive research, we can help answer long-standing puzzles about the nature of conceptual change in science. [p4]

What great scientists do are refined outgrowths of normal cognition.[p5]

Early philosophers of science borrowed terms from Gestalt psychology. This lead to a view that conceptual change was an abrupt kind of Gestalt switch. Historically, conceptual change is gradual.[p7]

The problem: how are successive scientific conceptualizations of a domain related to each other? Some argue that the concepts are incommensurable and others argue that they grow out of the old concepts. [p8]

The cognitive-historical approach can be used to attack this problem.

Outline of a Cognitive theory of conceptual change [p9]

Scientific theories are represented as 1. propositions, 2. mental models, and 3. images

Kinematics: "how to represent change."
Dymanics: "the processes through which change is created."[p10]

Conceptual structure changes in the following ways:

  1. Creation: New concepts are created (e.g. spin)
  2. Elimination: Concepts disappear (e.g. phlogiston)
  3. Descent: Concepts descend from others, with the same name and different meaning (e.g. mass and field)
  4. Absorption: Some absorb attributes of the previous (e.g. ether to field and space-time)
  1. If meaning is represented as a set of necessary and sufficient conditions then replacement, not change, is possible.
  2. Meaning cannot be represented as a set of necessary and sufficient conditions. Psychological research supports this.
Conceptual change in science is a problem solving process.[p12]

Throughout science history we find use of: [p12]

  1. Analogy
  2. Imagistic Reasoning
  3. Thought experimentation
  4. limiting case analysis
Faraday reasoned from an imagistic representation, which figured prominantly in the construction of his unified theory of electic and magnetic processes. [p14]

Wise (1979) argues that Maxwell (1890) used imagery to create the a mathematical representation.[p17]

Maxwell used analogy to make a theory of force processes in ether. Using continuum mechanics as a source, he transferred hypotheses: 1. underlying forces were newtonian 2. "continuity of transmission with the time delay necessary for a field theory" and 3. "unification through finding the mathematical expression for the dynamical relations through which one action gives rise to another." The first was an unsuccessful transfer.[p21]

He broke the problem into subproblems, and made mappings between the electromagnetc and the mechanical properties of a fluid vortex medium. The "mistakes" he made can be explained in terms of model-based reasoning: He, at first, posits that the "displacement current" is going in the wrong direction-- the direction that would be transferred direct in an analogy.

He made an abstract schema so that in the future he wouldn't need to make an analogy. [p23]

Maxwell created a non-newtonian system out of an analogy with a newtonian system.

Summary author's notes:

Back to the Cognitive Science Summaries homepage
Cognitive Science Summaries Webmaster:
JimDavies (jim@jimdavies.org)
Last modified: Thu Apr 15 11:07:19 EDT 1999