Although the phrase "factory model" didn't become a part of educational discourse until the 1980s, David B. Tyack, a leader in the field of educational history, provided a context for it in his history of American urban education, The One Best System (1974). "Just as eighteenth-century theologians could think of God as a clock-maker without derogation, so the social engineers searching for new organizational forms used the words 'machine' and 'factory' without investing them with the negative associations they evoke today."[19] Larry Cuban, another education historian, connects the metaphor to a particular mindset around the purpose of education.[20] In Pillars of the Republic, Common Schools and American Society, 1780-1860, Carl Kaestle (1983) offers:[21]