The following summary of the history of gravitational theory is based primarily on the work of Toulmin
and Goodfield (1961), Lloyd (1970, 1973), Grant (1971), Crombie (1952), and Kuhn (1957). A question to
keep in mind is whether a revolutionary model, as proposed by Thomas Kuhn, or an evolutionary model,
favored by Toulmin and Goodfield, more adequately describes the development of gravitational theory inhuman history.