 Newton became the exemplar of the modern scientist, and the Newtonian research program became the modern model of knowledge.Although absolute space, revealed by no experience, and a "force" acting at a distance discomforted Newton, he and physicists for some 200 years more would seldom suspect the fictional character of the Newtonian foundation, as they believed not that physical concepts and laws are "free inventions of the human mind", as Einstein in 1933 called them, but could be inferred logically from experience.Supposedly, Newton maintained that toward his gravitational theory, he had "framed" no hypotheses.