In the paper to which we have already made allusion several times, we have shown what light these facts throw upon the way in which the idea of kind or class was formed in humanity. In fact, these systematic classifications are the first we meet with in history, and we have just seen that they are modelled upon the social organization, or rather that they have taken the forms of society as their framework. It is the phratries which have served as classes, and the clans as species. It is because men were organized that they have been able to organize things, for in classifying these latter, they limited themselves to giving them places in the groups they formed themselves. And if these different classes of things are not merely put next to each other, but are arranged according to a unified plan, it is because the social groups with which they commingle themselves are unified and, through their union, form an organic whole, the tribe. The unity of these first logical systems merely reproduces the unity of the society. Thus we have an occasion for verifying the proposition which we laid down at the commencement of this work, and for assuring ourselves that the fundamental notions of the intellect, the essential categories of thought, may be the product of social factors. The above-mentioned facts show clearly that this is the case with the very notion of category itself. However, it is not our intention to deny that the individual intellect has of itself the power of perceiving resemblances between the different objects of which it is conscious. Quite on the contrary, it is clear that even the most primitive and simple classifications presuppose this faculty. The Australian does not place things in the same clan or in different clans at random. For him as for us, similar images attract one another, while opposed ones repel one another, and it is on the basis of these feelings of affinity or of repulsion that he classifies the corresponding things in one place or another.