Stanley Smith Stevens

Shortly after arriving in Massachusetts to begin a Ph.D., he left the LDS church, but continued to struggle with conflicting ideas of faith and science.

Stevens, who was noted for the clarity of his scientific writing, attracted to the group a number of participants whose aim was the "debabelisation of science".

The group was also influenced by the 5th Congress of the Unity of Science, which had been held at Harvard University in September 1939 and featured a number of well-known scientists from different disciplines.

One of his most influential contributions was his definition of a measurement scale defined by four types: Nominal, Ordinal, Interval, and Ratio.

(see Level of measurement) [11] He is the author of the operational theory of measurement, which “...in the broadest sense, is defined as the assignment of numerals to objects or events according to rules.”[12] In fact, the definition paraphrased Campbell's note from the Final Report of the so-called Ferguson's committee (joint committee of sections A, Mathematical and Physical Sciences, and J, Psychology, of the British Association for the Advancement of Science, held 1932–1940).