 The algebraic quality of language is especially important in scientific practice. Like x and y in algebra, scientific terms, such as Hartley’s “vibrations” or contemporary physicists’ “particles,” stand for unknowns, for which vibrating strings or grains of sand provide only loose and misleading analogies. Their presence is necessary for the practice of scientific discovery. Scientists employ “algebraic” terms in order to discern correlations and patterns that might otherwise remain unobserved: “Bringing an unknown quantity into a relation answers, in philosophy, to the art of giving names, expressing nothing definite … and then inserting these names … in all the enunciations of the phenomena, to see whether, from a comparison of these terms with each other, something definite in manner, degree, or mutual relation might result” (OM 1, prop. 87).