Where Do New Ideas Come From? A Heuristics of Discovery in the Cognitive Sciences

Scientifi c inquiry can be viewed as “an ocean, continuous everywhere and without a break or division,” in Leibniz’s words (1690/1951, p. 73). Hans Reichenbach nonetheless divided this ocean into two great seas, the context of discovery and the context of justifi cation. Philosophers, logicians, and mathematicians claimed justifi cation as a part of their territory and dismissed the context of discovery as none of their business, or even as “irrelevant to the logical analysis of scientifi c knowledge” (Popper, 1935/1959, p. 31). Their sun shines over one part of the ocean and has enlightened us on matters of justifi cation, but the other part of the ocean still remains in a mystical darkness where imagination and intuition reigns, or so it is claimed. Popper, Braithwaite, and others ceded the dark part of the ocean to psychology and, perhaps, sociology; but few psychologists have fi shed in these waters. Most did not dare or care. In this article, I will argue that discovery can be understood by heuristics (not a logic) of discovery. I will propose a heuristic of discovery that makes use of methods of justifi cation, thereby attempting to bridge the artifi cial distinction between the two. Furthermore, I will attempt to demonstrate that this discovery heuristic may not only be of interest for an a posteriori understanding of theory development, but also be useful for understanding limitations of present-day theories and research programs and for the further development of alternatives and new possibilities. The discovery heuristic that I call the “tools-to-theories” heuristic (see Gigerenzer, 1991, 2000) postulates a close connection between the shining and the dark part of Leibniz’s ocean: scientists’ tools for justifi cation provide the metaphors and concepts for their theories. The power of tools to shape, or even to become, theoretical concepts is an issue largely ignored in both the history and philosophy of science. Inductivist accounts of discovery, from Bacon to Reichenbach and the Vienna School, focus on the role of data, but do not consider how the data are generated or processed. Nor do the numerous anecdotes about discoveries, such as Newton watching an apple fall in his mother’s orchard while pondering the mystery of gravitation, Galton taking shelter from a rainstorm during a country outing when discovering correlation and regression toward mediocrity, and the stories about Fechner, Kekulé, Poincaré, and others, which link discovery to beds, bicycles, and bathrooms. What unites these anecdotes is the focus on the vivid but prosaic circumstances; they report the setting in which a discovery occurs, rather than analyzing the process of discovery.