But within this great whole, and part of it, are innumerable special systems of interaction, more or less distinct, more or less enduring, more or less conscious and intelligent. Nations, institutions, doctrines, parties, persons, are examples; but the whole number of systems, especially of those that are transient or indefinite, is beyond calculation. Every time I exchange glances with a man on the street a little process of special interaction and growth is set up, which may cease when we part or may be indefinitely continued in our thought. The more distinct and permanent wholes, like nations, institutions, and ruling ideas, attract peculiar study, but the less conspicuous forms are equally vital in their way. As to persons, they interest us more than all the rest, mainly because our consciousness has a bias in their favor. That is, having for its main function the guidance of persons, it is more vivid and choosing with reference to the personal phase of life than to any other. We know life primarily as persons, and extend our knowledge to other forms with some difficulty. Another notable thing about this strange complex is the overlapping and interpenetration of the various forms, so that each part of the whole belongs to more than one organic system—somewhat as in one of those picture-puzzles where the same lines form part of several faces, which you must discover if you can. Thus one’s own personality is one organic system; the persons he knows are others, and from one point of view all human life is made up of such personal systems, which, however, will be found on close inspection not to be separate but to interpenetrate one another. I mean that each personality includes ideas and feelings reflected from others. From another point of view the whole thing breaks up into groups rather than persons—into families, communities, parties, races, states. Each has a history and life of its own, and they also overlap one another. A third standpoint shows us the same whole as a complex of thoughts or thought-systems, whose _locus_, certainly, is the human mind, but which have a life and growth of their own that cannot be understood except by studying them as distinct phenomena. All are equally real and all are aspects of a common whole. Perhaps the first requisite in the making of a sociologist is that he learn to see things habitually in this way. If, then, we say that society is an organism, we mean, I suppose, that it is a complex of forms or processes each of which is living and growing by interaction with the others, the whole being so unified that what takes place in one part affects all the rest. It is a vast tissue of reciprocal activity, differentiated into innumerable systems, some of them quite distinct, others not readily traceable, and all interwoven to such a degree that you see different systems according to the point of view you take.[2]