[Sidenote: _Impossibility of a normative grammar._] Language has sometimes been regarded as a voluntary or arbitrary act. But at others the impossibility of creating language artificially, by an act of will, has been clearly seen. "_Tu, Caesar, civitatem dare potes homini, verbo non potes_" was once said to a Roman Emperor. And the æsthetic (and therefore theoretic as opposed to practical) nature of expression supplies the method of discovering the scientific error which lies in the conception of a (normative) _Grammar_, establishing the rules of correct speech. Good sense has always rebelled against this error. An example of such rebellion is the "So much the worse for grammar" attributed to Monsieur de Voltaire. But the impossibility of a normative grammar is also recognized by those who teach it, when they confess that to write well cannot be learned by rules, that there are no rules without exceptions, and that the study of Grammar should be conducted practically, by reading and examples, which should form the literary taste. The scientific reason of this impossibility lies in the principle that we have demonstrated: that a technique of the theoretical amounts to a contradiction in terms. And what could a (normative) grammar be, but precisely a technique of linguistic expression, that is to say of a theoretic fact? [Sidenote: _Didactic organisms._] The case in which Grammar is understood merely as an empirical discipline, that is to say, as a collection of schemes useful for learning languages, without any claim whatever to philosophic truth, is quite different. Even the abstractions of the parts of speech are in this case both admissible and useful. And we must tolerate as merely didascalic many books entitled "Treatises of Linguistic," where we generally find a little of everything, from the description of the vocal apparatus and of the artificial machines (phonographs) which can imitate it, to summaries of the most important I results obtained by Indo-European, Semitic, Coptic, Chinese, or other philologies; from philosophical generalizations as to the origin or nature of language, to advice on format, calligraphy and the arrangement of notes relating to philological work. But this mass of notions, here administered in a fragmentary and incomplete manner about language in its essence, about language as expression, resolves itself into notions of Æsthetic. Nothing exists outside _Æsthetic,_ which gives knowledge of the nature of language, and _empirical Grammar,_ which is a pedagogic expedient, save the _History of languages_ in their living reality, that is to say, the history of concrete literary productions, which is substantially identical with the _History of literature._ [Sidenote: _Elementary linguistic facts or roots._]