Introduction: General term rigidity and Devitt's rigid appliers

in this essay, i present a problem that originates in kripke's contention, in naming and necessity, that natural kind terms are rigid, namely, the problem of how to understand the notion of rigidity when it is applied to general terms. i also give an account, in a principled way, of the main theoretical options that seem to be available to solve that problem, and sketch the main features of michael devitt's proposal against that background.