The ideal language, projected by Leibniz, in which logical relations would be so transparent that, when people used the language, there would be no irresoluble dispute, but only the need to ‘calculate’. The idea is of a language whose categories and combinations accurately mirror the structure of reality itself, with no potentially misleading human perspective contaminating it. The lustre of this ideal has waxed and waned: it gains when a new notation (e.g. that of the calculus, or of modern logic) sweeps away old confusion, but loses ground when it appears that any language must be a reflection of possibly muddled ways of life, rather than an independent source of rational Enlightenment.