“Lincos does furnish us with an image of a language that is almost purely “mental” (its level of expression is supported by nothing more than electromagnetic phenomena). This reminds us of other languages which are, in one way or another, the heirs of the ancient search for the perfect language.
Computer languages, like BASIC or Pascal, are, in fact, a priori languages. They are not full languages because their syntax, though rigorous, is simplified and limited, and they remain parasitic on the natural languages which attach meanings to their empty symbols, which, for the most part, serve as logical connectors of the type if . . . then.
None the less, they are universal systems: they are comprehensible to speakers of differing natural languages and are perfect in the sense that they permit neither error nor ambiguity.
They are a priori, in that they are based not on the rules which govern the surface structures of natural languages, but rather, ideally, on a presumed deep grammar common to all natural languages.
They are, finally, philosophical because they presume that this deep grammar, based on the laws of logic, is the grammar of thought of human beings and machines alike. They also exhibit the two limitations inherent in philosophical a priori languages:
(1) their rules of inference are drawn from the western logical tradition, and this may mean, as many have argued, that they reflect little more than the basic grammatical structures common to the Indo-European family of languages;
(2) their effability (sic) is limited; that is, they are capable of expressing only a small proportion of what any natural language can express.
The dream of a perfect language which covers all the meanings and connotations of the vocabulary of a natural language, and in which human beings and machines can engage in “meaningful” conversations (or machines can draw inferences as happens in natural languages), underlies much of contemporary research into artificial intelligence.
Machines are provided, for example, with rules of inference by which they can “judge” whether or not a certain story is coherent, or decide that, if someone is ill, then someone needs medical assistance–and so on.
By now, the literature on this subject is vast, and the proposed systems are many: they run from those that still adhere to the ideal of a componential semantics based on primitives, to those that furnish the machine with schemes of action or a typology of “frames,” “scripts” and “goals.”
In general all of these projects succeed in solving certain problems only through imposing ad hoc solutions, which work only for local portions of the range of action of natural languages.”
Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 310-2.