applies to all things examined before a certain time t just in case they are green, but also to other things just in case they are blue and not examined before time t. If we examine emeralds before time t and find that emerald a is green, emerald b is green, and so forth, each will confirm the hypothesis that all emeralds are green. However, emeralds a, b, c,..etc. also confirm the hypothesis that all emeralds are grue. Thus, before time t, the apparently law-like statements "All emeralds are green" and "All emeralds are grue" are equally well confirmed by observation, but obviously "All emeralds are grue" is not a law-like statement. Goodman's example showed that the difficulty in determining what constitutes law-like statements is far greater than previously thought, and that once again we find ourselves facing the initial dilemma that "anything can confirm anything". Nominalism and mereology Goodman, along with Stanislaw Lesniewski, is the founder of the contemporary variant of nominalism, which argues that philosophy, logic, and mathematics should dispense with set theory. Goodman's nominalism was driven purely by ontological considerations. After a long and difficult 1947 paper coauthored with W. V. O. Quine, Goodman ceased to trouble himself with finding a way to reconstruct mathematics while dispensing with set theory – discredited as sole foundations of mathematics as of 1913 (Russell and Whitehead, in Principia Mathematica). The program of David Hilbert to reconstruct it from logical axioms was proven futile in 1931 by Gödel. Because of this and other failures of seemingly fruitful lines of research, Quine soon came to believe that such a reconstruction was impossible, but Goodman's Penn colleague Richard Milton Martin argued otherwise, writing a number of papers suggesting ways forward. According to Thomas Tymoczko's afterword in New directions in the philosophy of mathematics, Quine had "urged that we abandon ad hoc devices distinguishing mathematics from science and just accept the resulting assimilation", putting the "key burden on the theories (networks of sentences) that we accept, not on the individual sentences whose significance can change dramatically depending on their theoretical context." In so doing, Tymoczko claimed, philosophy of mathematics and philosophy of science were merged into quasi-empiricism: the emphasis of mathematical practice as effectively part of the scientific method, an emphasis on method over result. The Goodman–Leonard (1940) calculus of individuals is the starting point for the American variant of mereology. While the exposition