“During the Enlightenment there began to develop a critical attitude towards any attempt to construct a system of a priori ideas. It was a critique founded, in large part, upon the considerations advanced by Leibniz.
Thus it was in terms that closely recalled Leibniz’s own description of an ideal library that, in his introduction to the Encyclopédie, d’Alembert was to sound the death knell for projects for philosophical a priori languages.
Presented with the practical problem of organizing an encyclopedia and justifying the way that it divided its material, the system of scientific knowledge began to take on the appearance of a labyrinth, a network of forking and twisting paths that put paid to any notion that knowledge might be represented in a tree diagram of any sort.
Knowledge might still be divided into branches, “some of which converge at a common center; and, since, starting from the center, it is impossible to follow all the branches at once, the choice [of pathway] is determined by the nature of the different intellects.”
The philosopher was whoever discovered the hidden passageways within that labyrinth, the provisional interconnections, the web of mutually dependent associations which constituted such a network as a geographical representation.
For this reason the authors of the Encyclopédie decided that each single article would appear as only one particular map, which, in its small way, might reflect the entire global map:
“objects approach each other more or less closely, presenting different aspects according to the perspective chosen by the particular geographer [ . . . ].
Thus it is possible to imagine that there are as many systems of human knowledge as there are representations of the world constructed according to differing projections [ . . . ].
Often, an object placed in one particular class on account of one or another of its properties may reappear in another class because of other properties.”
Following the suggestion of Locke, the Enlightenment was less concerned with the search for perfect languages than with the provision of therapies for already existing ones.
After denouncing the limits of natural languages, Locke (Essay, III, X) had passed to an analysis of the abuse which must occur whenever words are used that do not correspond to clear and distinct ideas, whenever they are used inconsistently, whenever they are employed with the affectation of obscurity, whenever words are taken for things, whenever they are used for things which possess no meaning, and whenever we imagine that others must necessarily associate with the words we use the same ideas as we do.
Locke fixed a set of norms to combat these abuses, and, since Locke was not concerned with lexical or syntactical reform, but simply with subjecting usage to a measure of vigilance and philosophical common sense, these norms had no bearing on the theme of philosophical languages.
Instead of a systematic reform of language, Locke modestly suggested that we be more conscientious in the way we use words to communicate with one another.
This was to be the line adopted by the encyclopedists of the Enlightenment and those whom they inspired.
The encyclopedists launched their attack on philosophical a priori languages principally in their entry under the heading “Caractère,” which was the result of the collaboration of several authors.
Du Marsais made an initial distinction between numerical characters, characters representing abbreviations, and literal characters; these last were further subdivided into emblematic characters (still the accepted interpretation of hieroglyphics) and nominal characters, primarily the characters of the alphabet.
D’Alembert accepted the criticisms that had traditionally been made of the characters used in natural languages, and then discussed the various projects for the construction of real characters, showing an extensive knowledge of the projects in the previous century.
It was a discussion which often confused characters that were ontologically real, that directly expressed, that is, the essence of the things they represented, with characters that were only logically real, capable, that is, of expressing by convention a single idea unequivocally. Still, d’Alembert advanced a number of criticisms that applied equally to both types.
In contrast to those of the seventeenth century, philosophers in the Enlightenment had radically changed the focus of their reflection on language. It now seemed clear that thought and language influenced each other, each proceeding with the other step by step, and that, consequently, language, as it evolved, would constantly modify thought.
Thus it no longer made sense to accept the rationalist hypothesis of a single grammar of thought, universal and stable, which all languages in one way or another reflected. No system of ideas postulated on the basis of abstract reasoning could thus ever form an adequate parameter of and criterion for the formation of a perfect language.
Language did not reflect a preconstituted mental universe, but collaborated in its growth.
The Idéologues demonstrated the impossibility of postulating a universal way of thinking, independent of the human semiotic apparatus. Destutt de Tracy (Eléments d’idéologie, I, 546, n.) argued that it was not possible to confer on all languages the attributes of algebra. In the case of natural languages:
“we are often reduced to conjectures, inductions, and approximations [ . . . ]. Almost never can we have a perfect certainty that an idea which we have constructed for ourselves under a certain sign and by various means is really utterly and entirely the same as the idea that those who taught us the sign as well as anyone else who might subsequently use the sign might attribute to it.
Hence words may often, insensibly, take on differences in meaning without anyone noting these changes; for this reason we might say that while every sign is perfectly transparent for whomever invents it, it is somewhat vague and uncertain for those who receive it [ . . . ].
I might even carry this further: I said that every sign is perfect for whomever invents it, but this is only really true at the precise instant when he invents the sign, for when he uses this same sign in another moment in his life, or when his mind is in another disposition, he can no longer be entirely sure that he has gathered up under this sign the same collection of ideas as he had the first time he used it.” (pp. 583-5).
Tracy understood that the prerequisite of all philosophical languages was the absolute and univocal correspondence between signs and the ideas they represented. An examination, however, of the seventeenth century English systems led him to the conclusion that “it is impossible that the same sign possess the same meaning for all who use it [ . . . ]. We thus must give up the idea of perfection.” (Eléments d’idéologie, II, 578-9).
This was a theme that was common to empiricist philosophy, to which all the Idéologues referred. Locke had already noted that although the names glory and gratitude were
“the same in every Man’s mouth, through a whole country, yet the complex, collective Idea, which everyone thinks on, or intends by that name, is apparently very different in Men using the same language. [ . . . ]
For though in the Substance Gold, one satisfies himself with Color and Weight, yet another thinks solubility in Aqua Regia, as necessary to be join’d with that Color in his Idea of Gold, as any one does its Fusibility; Solubility in Aqua Regia, being a Quality as constantly join’d with its Color and and Weight, as Fusibility, or any other; others put its Ductility or Fixedness, etc. as they had been taught by Tradition and Experience.
Who, of all these, has establish’d the right termination of the word Gold?” (Essay, III, IX, 8, 13).
Returning to the Idéologues, Joseph-Marie Degérando, whose criticisms of Wilkins we have already encountered, observed (Des signes et l’art de penser considérés dans leur rapports mutuels, 1800) that the ensemble of associated ideas represented by the word man would be more extensive in the mind of a philosopher than in that of a common laborer, and that the word liberty could not have meant in Sparta what it did in Athens (I, 222-3).
The impossibility of elaborating a philosophic language is finally due to the fact that since languages develop through a set of stages, a development that the Idéologues delineated with great precision, there was no way of deciding the linguistic stage of development that a perfect language should represent.
Choosing to reflect one stage rather than another, a philosophical language will then continue to reflect all the limitations of that linguistic stage, while just to overcome these limitations humanity had passed to further and more articulate stages.
Once it had been perceived that the process of linguistic change is continuous, that language is subject to change not only at its prehistoric point of origin, but also in the present day, it became obvious that any thought of reviving the idea of a philosophic language was destined to fail.”
Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 288-92.