Although this note is prompted by the recent exchange between Gellner [2], [3] and Needham [4], I shall ignore the issues raised by Gellner's specification for an ideal language. I am concerned here only with Needham's statement that ‘biology is one matter and descent is quite another, of a different order’ which, it will be remembered, Gellner treats as Needham's first error. I write under a sense of obligation, for I discussed this matter with Gellner in 1955 while he was preparing his first article and my arguments then were phrased similarly to those advanced by Needham. It appears that I did not make myself clear to Gellner and I shall try again. I do not wish to attack or defend either protagonist; each is quite able to look after himself. Therefore I propose neither to examine where they have misunderstood each other, nor to discuss the difference between kinship (Gellner's starting-point) and descent (Needham's), but simply to state the connexion, as I see it, between physical and social kinship.