“Thus all of the ingenuity expended upon the invention of philosophic a priori languages allowed Leibniz to invent a language of a radically different type, which–though remaining a priori–was no longer a practical, social instrument but rather a tool for logical calculation.
In this sense, Leibniz’s language, and the contemporary language of symbolic logic that descended from it, are scientific languages; yet, like all scientific languages, they are incapable of expressing the entire universe, expressing rather a set of truths of reason.
Such languages do not qualify as a universal language because they fail to express those truths that all natural languages express–truths of fact. Scientific languages do not express empirical events.
In order to express these we would need “to construct a concept which possesses an incalculable number of determinations,” while the completely determined concept of any individual thing or person implies “spatial-temporal determinations which, in their turn, imply other spatial-temporal successions and historical events whose mastery is beyond the human eye, and whose control is beyond the capacity of any man.” (Mugnai 1976: 91).
None the less, by anticipating what was to become the language of computers, Leibniz’s project also contributed to the development of programs well adapted for the cataloguing of the determinations of individual entities, which can tell us that there exists an entity called Mr. X such that this entity has booked a flight from A to B.
We may well fear that by controlling our determinations so well the computer eye has begun to infringe on our privacy, checking on the hour in which we reserved a room in a certain hotel in a certain city. This, then, is one of the side-effects of a project that commenced with the idea of expressing a merely theoretical universe populated with universal ideas such as goodness, angels, entity, substance, accidents, and “all the elephants.”
Dalgarno could never have imagined it. Passing through the mathematical filter of Leibniz, renouncing all semantics, reducing itself to pure syntax, his philosophical a priori language has finally managed to designate even an individual elephant.”
Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 287-8.