much higher degree owing to the plasticity of the material in which the signs can be, as it were, coined. It is true that at first the development of gesture-language is the easier, just because it deals with a greater number of natural signs; hence in the earlier phases of human development it is only supplemented by sound-language; a relation which afterwards reverses itself, until finally the sound-language as fixed in writing acts by itself alone and lacks even the explanation which the speaker gives to his words by the modulation of his voice. The progress from sensuous and particular to conceptual and universal communications develops itself in general in the same relation.
12. For out of articulate sounds arise almost exclusively the completely different genus of signs, which we oppose to natural signs as being artificial signs. Here there is no longer any natural relation or bond between the sign and that which it signifies; it is the human will alone which produces the relation of ideal association through which the word becomes sign of the thing, as also the relation through which writing becomes sign of the word, and the letter-unit becomes sign of the sound-unit. But the separation of artificial from natural signs is a process which moves gradually and in imperceptible transitions; the memory has to accustom itself to signs which are more and more unnatural, therefore more inconvenient; and which nevertheless are for human purposes facilitations, because the natural signs do not suffice, or would cost a far greater expenditure of trouble to be sufficiently elaborated. The natural signs upon which linguistic sounds are based are sometimes involuntary expressive movements of the vocal organs; sometimes imitations, i.e., copies, of heard and familiar sounds; and finally, sometimes they are attempts, formed according to the principles of analogy and contrast, to reproduce the impressions of objects, which have then, favoured by relatively fortuitous circumstances, maintained themselves, i.e., have entered into a more or less firm connexion with the ideas (perceptions or recollections) of the objects.
13. A certain word has a certain meaning, i.e., it is sign of a certain (perceivable or thinkable) object, according to the will of one or more persons. When it is according to the will of one person, then either he alone understands the sign, and then it is a private sign; or it is understood by others also, and then it is a social sign. Here again it is a question of transitions. Understanding is itself a kind of willing, it is the will of recognition, of acceptance, i.e., of appropriation, and thus understanding in common is like
