Lippmann also makes much of the idea of social sets. His remarks could well be labeled one of the understanding definitions of social class. He writes: ¹⁰⁰

Usually the distinguishing mark of a social set is the presumption that the children intermarry. To marry outside the set involves, at the very least, a moment of doubt before the engagement can be approved. Each social set has a fairly clear picture of its relative position in the hierarchy of social sets...

Whatever the tests of admission, the social set when formed is not a mere economic class, but something more nearly resembling a biologic clan. Membership is intimately connected with love, marriage and children, or, to speak more exactly, with the attitudes and desires that are involved. In the social set, therefore, opinions encounter the canons of Family Tradition, Respectability, Propriety, Dignity, Taste and Form, which make up the social set's picture of itself, a picture assiduously implanted in the children.

Since each community is made up of a hierarchy of social sets, it is logical to refer to a social class as the sum total of all the like social sets within the cultural area. A family, in moving to another part of the United States or Canada, for instance, would, after the initial stage of social introductions and of getting acquainted, find itself in the social circle most like the one from which it came, still within the same social class, however.

With Schumpeter, it may be concluded that the "family, not the physical person, is the true unit of class theory." ¹⁰¹

In conclusion, too, the importance of social class considerations in all human relationships cannot be overemphasized. Social class enters into every handclasp, every greeting, every appointment. As one eminent sociologist has stated: ¹⁰²

The legal and economic order supposedly makes no distinction between the gentleman and the lady on one hand and "hoi polloi" on the other, but in ordinary affairs this distinction is much more important than are other varieties ... the clumsy divisions of the political or economic order are of no help. Even professional or occupational groupings do not afford a secure basis for differentiation.