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.
There are also cases where we are able to perceive the reasons which inspired this. The two phratries were very probably the original and fundamental bases for these classifications, which were consequently bifurcate at first. Now, when a classification is reduced to two classes, these are almost necessarily conceived as antitheses; they are used primarily as a means of clearly separating things between which there is a very marked contrast. Some are set at the right, the others at the left. As a matter of fact this is the character of the Australian classifications. If the white cockatoo is in one phratry, the black one is in the other; if the sun is on one side, the moon and the stars of night are on the opposite side.[444] Very frequently the beings which serve as the totems of the two phratries have contrary colours.[445] These oppositions are even met with outside of Australia. Where one of the phratries is disposed to peace, the other is disposed to war;[446] if one has water as its totem, the other has earth.[447] This is undoubtedly the explanation of why the two phratries have frequently been thought of as naturally antagonistic to one another. They say that there is a sort of rivalry or even a constitutional hostility between them.[448] This opposition of things has extended itself to persons; the logical contrast has begotten a sort of social conflict.[449]