On methodology

“I did not make a deliberate decision to adopt a particular methodology: I had the good fortune to work alongside gifted colleagues from backgrounds in different disciplines, and their various techniques seemed to be producing results. With hindsight, I should describe how one learns from both experiments and intelligent software in terms of the distinction that philosophers draw between the correspondence and the coherence theories of truth. An assertion is true according to the first theory if it corresponds to some state of affairs in the world; true according to the second if it coheres with a set of assertions constituting a general body of knowledge. Experiments provide information about correspondence with the facts, but they exert a dangerous pull in the direction of empirical pedantry, where the only things that count are facts, no matter how limited their purview. Computer programs provide information about the coherence of a set of assumptions, but they exert a dangerous pull in the direction of systematic delusion, where all that counts is internal consistency, no matter how remote from reality. Give up one approach and you turn into a Gradgrind, the teacher in Dicken’s novel Hard Times, whose only concern is with the facts; give up the other and you become an architect for the Flat Earth Society. Those, at least, are the dangers.”

From the prologue to Mental Models by Philip Johnson-Laird