Edisonian Approach - Trial and Error (hunt and Try)

Trial and Error (hunt and Try)

Based on detailed study of his notebooks a number of scholars have pointed out that Edison generally resorted to trial and error in the absence of adequate theories. For example, in developing the carbon microphone (or carbon grain transmitter) that became the basis of telephones of the next hundred years, Edison and his co-workers tried hundreds of substances, finally settling on lamp black as the variable resistance medium. Edison could not use theory to solve this problem because, as Gorman and Carlson note, at the time "no one had yet developed a chemical theory that Edison could have used to identify a form of carbon with the electrical properties he wanted" (Gorman and Carlson, 1990).

Edison was not alone in using trial and error (more accurately termed by Hughes as "hunt and try") because he, like others, was working at the edges of contemporary theory. Thomas Midgley (who held a PhD and was the inventor of tetraethyl lead and halogenated hydrocarbon refrigerants) said of trial and error, "the trick is to turn a wild goose chase into a fox hunt" (quoted in Hughes 2004).

Such leading edge work requires a combination of theory and empirical approaches. Edison used a "bottom-up theoretical approach" when developing electric lighting, undertaking detailed analysis of the whole electric lighting system based on Joule's and Ohm's laws. This led him to conclude that to be economically successful he had to produce a high resistance lamp (around 100 ohms). (Friedel and Israel 1987) Once he had established the need for a high resistance lamp he was faced with a lack of optical emission theories to describe the behaviour of materials when heated to incandescence. It was then that he embarked on a systematic search for a suitable material and for the techniques to manufacture it in economic volumes.