The single most important stimulus to my thought came by chance when I took a course from Robert Redfield entitled "Folk Society." …His approach was to set up antithetical ideal types, expecting to locate any actual human community somewhere along the spectrum of opposites his fieldwork had suggested to him.... But in 1936 his typology had no time dimension. I was so strongly attracted to his scheme that it is scarcely an exaggeration to describe my subsequent intellectual effort as an attempt to explore the missing time dimension of social change as Redfield envisaged it, not in Yucatan but around the whole earth and across recorded time.

The Pursuit of Truth: A Historian's Memoir (2005)