+45. Consistency in the mores.+ The tendency of the mores of a period to consistency has been noticed (sec. 5). No doubt this tendency is greatly strengthened when people are able to generalize "principles" from acts. This explains the modern belief that principles are causative. The passion for equality, the universal use of contract, and the sentiments of humanitarianism are informing elements in modern society. Whence did they come? Undoubtedly they came out of the mores into which they return again as a principle of consistency. Respect for human life, horror at cruelty and bloodshed, sympathy with pain, suffering, and poverty (humanitarianism), have acted as "causes" in connection with the abolition of slavery, the reform of the criminal law and of prisons, and sympathy with the oppressed, but humanitarianism was a generalization from remoter mores which were due to changes in life conditions. The ultimate explanation of the rise of humanitarianism is the increased power of man over nature by the acquisition of new land, and by advance in the arts. When men ceased to crowd on each other, they were all willing to adopt ideas and institutions which made the competition of life easy and kindly. +46. The mores of subgroups.+ Each class or group in a society has its own mores. This is true of ranks, professions, industrial classes, religious and philosophical sects, and all other subdivisions of society. Individuals are in two or more of these groups at the same time, so that there is compromise and neutralization. Other mores are common to the whole society. Mores are also transmitted from one class to another. It is necessary to give precision to the notion of classes. +47. What are classes?+ Galton[66] made a classification of society by a standard which he did not strictly define. He called it "their natural gifts." It might be understood to be mental power, reputation, social success, income from societal work, or societal value. Ammon took up the idea and developed it, making a diagrammatic representation of it, which is reproduced on the following page.[67] +48.+ If we measure and classify a number of persons by any physical characteristic (stature, weight) we find that the results always fall under a curve of probable error. That they should do so is, in fact, a truism. If a number of persons with different degrees of power and resistance are acted on by the same influences, it is most probable that the greatest number of them will reach the same and a mean degree of self-realization, and others in proportion to their power and resistance. The fact has been statistically verified so often, and for such a great variety of physical traits, that we may infer its truth for all traits of mind and character for which we have no units, and which we cannot therefore measure or statistically classify.