Leibniz is remembered as the tireless champion of a universal language, or "characteristic," modelled on symbolic algebra. In the eyes of many today, this makes him a brilliant forerunner of the computer, or even of artificial intelligence. The reality is far subtler…
Throughout his life, Gottfried Wilhelm Leibniz (1646–1716) was fascinated by the project of "a […] universal language capable of putting every notion and subject in good order and helping foreign nations communicate their thoughts". Many texts addressing these questions have now been translated into French and are therefore available to everyone, notably in the volume edited by Jean-Baptiste Rauzy for PUF under the title Recherches générales sur l’analyse des notions et des vérités (General Research on the Analysis of Notions and Truths).

Leibniz never missed an opportunity to present his grand programme, stressing that, unlike the many other contemporary attempts at a lingua universalis, it would have the advantage of being operational. Modelled on algebra, it would thus combine all the benefits of an " art of discovery and judgement ". From a very young age, before he was even 20 and while writing a dissertation on the combinatorial art (De arte combinatoria, 1666), he delighted in dreaming of " an analysis of human thoughts by means of a kind of alphabet of primitive notions " and a " universal script " (scriptura universalis) in which those notions could then be set down. Indeed, he would often refer to this as his original moment of inspiration : "For my part, while I was still a child, studying only the precepts of ordinary logic and knowing nothing of mathesis, it occurred to me, prompted by I know not what impulse, that one could devise an analysis of notions from which, through a certain combination, truths might emerge that could be evaluated as if they were numbers."

This is the familiar dream of a universal "characteristic"—that is, a symbolic script—and, with it, a formal language in which we would merely have to set down all our thoughts and exclaim Calculemus!—or its French equivalent, in the spelling of the period, meaning "Let us reckon!" Leibniz wrote the following in French: "It is therefore clear that, if characters or signs could be found that expressed all our thoughts as plainly and exactly as arithmetic expresses numbers or geometrical analysis expresses lines, then in every subject, insofar as it is amenable to reasoning, we could do everything that can be done in arithmetic and geometry. (…) Furthermore, everyone would agree on what had been found or concluded, since the calculation could easily be checked (..). And if anyone doubted what I had asserted, I would say to him: Let us reckon, Sir; and thus, taking up pen and ink, we would soon settle the matter." (La vraie Méthode (The True Method), 1677—the spelling has been modernized).
These passages, along with others in the same vein, are cited time and again to cast Leibniz variously as a forerunner of modern symbolic logic, or even logicism—the idea that all mathematics is founded on logic—or of computers and, nowadays, even artificial intelligence.