Making More Plausible What is Hard to Believe: Historical Justifications and Illustrations of Newton's Third Law

It has been claimed that conceptual change in students is more likely to occur if the alternative to present conceptions is a plausible one for the students. Many studies have shown that students today do not believe Newton's law of action and reaction and in this paper ways in which its plausibility might be enhanced are explored. In it the various justifications of the law by means of which Newton and those who came after him attempted to make it more plausible for their contemporaries are discussed.