Sir Thomas Young Sir Thomas Young and and Statistical Evidence of Historical Relationship Statistical Evidence of Historical Relationship William J. Poser William J. Poser University of Pennsylvania University of Pennsylvania It has long been recognized that the demonstration of genetic affiliation between languages involves a statistical element, in that it is necessary to exclude the possibility of congruences between languages being due to chance, but it has generally been considered both difficult and unnecessary to engage in explicit statistical calculation. This is largely due to the belief that the comparative method as traditionally applied so reduces the possibility of chance as virtually to exclude it. The controversy that has latterly raged over certain claims of distant genetic relationship, where the evidence adduced is scant and no reconstruction of the history of the putatively related languages follows and confirms the claim of affiliation, has brought about a renewed interest in quantitative methods (e.g. Ringe 1992, Kessler 2001). Although the mathematical aspects of comparative linguistics are still imperfectly understood, the subject has a long history, much of which appears, from the very spotty references one finds, to be generally unknown. In this note I wish to draw attention to, and comment upon, what I believe to be the first work on this topic, by Sir Thomas Young, M.D. (1773-1829). Sir Thomas was a scientist and scholar of wide-ranging interests. Although he held a medical degree from Gottingen, his academic appointment was as professor of physics. His contributions include the wave theory of light, the theory of interference of light, the three primary color theory of color vision and the explanation for astigmatism. That Young should have adverted to a linguistic topic is not surprising. Having learned French, German, Latin, Greek, Hebrew and Arabic as a boy, he had a serious interest in linguistics. In 1813 he coined the term ‘Indo-European' by which this family has since been known in English (Koerner 1989:154-157). He made the first and only significant advance in the decipherment of Egyptian hieroglyphic writing prior to Champollion, correctly reading several cartouches; indeed, his method was the same as Champollion’s. Had he realized that the phonological component of Egyptian writing was not restricted to royal names, it would probably be Young and not Champollion whose name would be associated with the full decipherment of Egyptian. Young’s treatment of linguistic relationship appears in a letter