The nature of the concept, thus defined, bespeaks its origin. If it is common to all, it is the work of the community. Since it bears the mark of no particular mind, it is clear that it was elaborated by a unique intelligence, where all others meet each other, and after a fashion, come to nourish themselves. If it has more stability than sensations or images, it is because the collective representations are more stable than the individual ones; for while an individual is conscious even of the slight changes which take place in his environment, only events of a greater gravity can succeed in affecting the mental status of a society. Every time that we are in the presence of a _type_ of thought or action which is imposed uniformly upon particular wills or intelligences, this pressure exercised over the individual betrays the intervention of the group. Also, as we have already said, the concepts with which we ordinarily think are those of our vocabulary. Now it is unquestionable that language, and consequently the system of concepts which it translates, is the product of collective elaboration. What it expresses is the manner in which society as a whole represents the facts of experience. The ideas which correspond to the diverse elements of language are thus collective representations. Even their contents bear witness to the same fact. In fact, there are scarcely any words among those which we usually employ whose meaning does not pass, to a greater or less extent, the limits of our personal experience. Very frequently a term expresses things which we have never perceived or experiences which we have never had or of which we have never been the witnesses. Even when we know some of the objects which it concerns, it is only as particular examples that they serve to illustrate the idea which they would never have been able to form by themselves. Thus there is a great deal of knowledge condensed in the word which I never collected, and which is not individual; it even surpasses me to such an extent that I cannot even completely appropriate all its results. Which of us knows all the words of the language he speaks and the entire signification of each?