LANGUAGE is treated among the subject matters of the theoretic, practical, and productive sciences. It is related to its bases in the organism and the soul of man; its practical efficacy as rule of prudence and as instrument of communication is examined in determining the proportion which is sought in virtuous action and the bond of justice by which states are held together; its artistic realizations are discovered in the constructions of poetry. Yet in each of these sciences in which it is a subject matter language is also an instrument of inquiry and statement, and, in addition, it serves other functions beyond these scientific uses. The analysis of things is presented in language; and, when language is used scientifically, criteria by which to test statement and argument are sought in the subject matters which the sciences treat. Even the language of science, moreover, may be viewed not only in terms of its adaptation to the processes of inquiry and proof relative to the subject matter of the sciences but also in terms of its development in acquisition and use relative to processes in the mind of the inquirer and in terms of its elements and combinations relative to the symbolic system employed in stating and formulating the results of inquiry. The uses of language, however, do not all follow the model of scientific inquiry and proof, nor are they limited to the devices by which science is acquired and set forth. In its scientific uses, language, as well as the thought it expresses, is made to conform as closely as possible to a subject matter. Language may also express a normative rule for action which, if successfully performed, may alter the actual situation; and the criteria for such rules of action must be sought in potentialities that may or may not be actualized or in communities that may or may not be established or that may be preserved or destroyed. Language may, again, be determined by the relation between speaker and audience, and the criteria for expression no less than the conception of subject matter must then be sought in thoughts and emotions already possessed or to be conveyed. Language may, finally, find its efficacy primarily in the instrumentalities of words and style, even to the extent of making the improbable seem plausible and the unconventional acceptable; and the criteria for thought and the conception of nature must then be sought in the development of the argument and in the elements and combinations by which it is expressed. The development of an argument may thus be determined by science or by prudence or by art-or by dialectical, sophistical, or rhetorical supplements or approximations to such developments -and thoughts and occurrences may be set forth in expressions determined by consideration, real or apparent, of truth and probability or of justice and expediency or of form and pleasure. Arguments (Xoyot) are used not only for proof and teaching but also for persuasion and regulation, for communication and artistic construction. The variety of the uses of language and of criteria for the judgment of those uses depends on the same characteristics of