I discuss the Pythagorean law of small numbers and its use in interpretations of our sensory discriminations of consonance vs. dissonance. It seems that the fact of non-western musical traditions contradicts the law and forces us to interpret the discriminations as acquired and subjective. I would like to show that this is a wrong interpretation, because it is based on the irrelevant empirical evidence. It does not take into account the correct mathematical and physical explanation of the law, provided by Helmholtz’s theory in 1877 and corroborated by Plomp-Levelt experiment in 1965.