This same social character leads to an understanding of the origin of the necessity of the categories. It is said that an idea is necessary when it imposes itself upon the mind by some sort of virtue of its own, without being accompanied by any proof. It contains within it something which constrains the intelligence and which leads to its acceptance without preliminary examination. The apriorist postulates this singular quality, but does not account for it; for saying that the categories are necessary because they are indispensable to the functioning of the intellect is simply repeating that they are necessary. But if they really have the origin which we attribute to them, their ascendancy no longer has anything surprising in it. They represent the most general relations which exist between things; surpassing all our other ideas in extension, they dominate all the details of our intellectual life. If men did not agree upon these essential ideas at every moment, if they did not have the same conception of time, space, cause, number, etc., all contact between their minds would be impossible, and with that, all life together. Thus society could not abandon the categories to the free choice of the individual without abandoning itself. If it is to live there is not merely need of a satisfactory moral conformity, but also there is a minimum of logical conformity beyond which it cannot safely go. For this reason it uses all its authority upon its members to forestall such dissidences. Does a mind ostensibly free itself from these forms of thought? It is no longer considered a human mind in the full sense of the word, and is treated accordingly. That is why we feel that we are no longer completely free and that something resists, both within and outside ourselves, when we attempt to rid ourselves of these fundamental notions, even in our own conscience. Outside of us there is public opinion which judges us; but more than that, since society is also represented inside of us, it sets itself against these revolutionary fancies, even inside of ourselves; we have the feeling that we cannot abandon them if our whole thought is not to cease being really human. This seems to be the origin of the exceptional authority which is inherent in the reason and which makes us accept its suggestions with confidence. It is the very authority of society,[19] transferring itself to a certain manner of thought which is the indispensable condition of all common action. The necessity with which the categories are imposed upon us is not the effect of simple habits whose yoke we could easily throw off with a little effort; nor is it a physical or metaphysical necessity, since the categories change in different places and times; it is a special sort of moral necessity which is to the intellectual life what moral obligation is to the will.[20]