 A much-discussed example of a robust experimental result from the physical sciences is the numerical value obtained for Avogadro’s number (6.022 x 1023) at the beginning of the 20th Century by using no less than thirteen independent methods according to the physicist Jean Perrin (Nye 1972). Salmon (1984) has argued that this provided a strong justification for belief in the existence of atoms by way of a common-cause argument. On Salmon’s view, the existence of atoms can be inferred as the common cause of Perrin’s thirteen different determinations of Avogadro’s number. Others have construed robustness arguments more along the lines of Putnam’s “no miracle” argument for scientific realism, according to which the assumption of the reality of some theoretical entities is the best explanation for the predictive success of theories or, in the case of robustness, for the agreement of experimental results (Weber 2005, Ch. 8; Stegenga 2009).