ABSTRACT
We encounter not only simple bodies, which at once impress us as constituting units (for example, a sheet of paper, a cow, John Smith), but also meet with compound units, intricate quantities. When considering the movement of the population, we may say: the number of male infants born within a certain interval of time has increased so much. We then regard this “number of male infants” as a total quantity, existing apart from the various units, and considered as a unit in itself (a “statistical aggregate”). We also speak of a forest, a class, human society, and at once find that we are dealing with compound quantities: we regard these quantities as individual quantities, but we likewise know that these wholes consist of elements having a certain degree of independence: the forest consists of trees, bushes, etc.; the class, of the various persons constituting it, etc. Such composite quantities are called aggregates.
