Then the whole matter is further complicated by making intelligence depend upon the presence of ideas. Intelligence implies learning, and then the author says: "I shall limit learning to modifications in the behavior of an animal capable of forming images when such modifications are due to the ability to form images." This last criterion of learning is in principle inapplicable below man, and in the form stated would not truly describe most human learning, which is apparently very little dependent on the presence of ideas. Professor Parmelee admits that it may never be possible to apply his criteria of intelligence to any animal in practice. Similar objection might be made to his insistence in one place that emotion is merely the subjective side of instinct and in another to the assertion that it is nothing but sensation, and then in one of the last chapters making emotion an active force in producing social organization, alongside of and in addition to instinct. The entire discussion in this part of the book, it seems to the reviewer, is a curious mixture of over subtlety and great dogmatism in drawing distinctions of his own coupled with complete failure to appreciate distinctions which have long been found of great value to the psychologist.
In the last four chapters are discussed the forces that make for social evolution. A long summary based on Wheeler and Wasmann is given of the social phenomena as they appear among the ants with casual references to the other social insects. The conclusion is reached that insect societies depend mainly upon instincts. More briefly are discussed the facts of association among the vertebrates, from the fishes to man. The forces that contribute to the formation of societies ate classed under three groups, external or environmental, such as the restricted areas of food suitable to a species, the distribution of temperature, etc., and two internal forces, primarily instinct and intelligence. Each is of value only in so far as it shows utility for survival. The whole attitude maybe shown in this summary, p. 393. " Man is very social, because he is weak as compared with many species which prey upon him, because his young are born very helpless and remain so for a long time, and because he has a highly developed nervous system which furnishes the basis for a high degree of intelligence, thus making possible a high degree of mental interaction from which result a good deal of pleasure and a great deal of cooperation and mutual aid in the form of a social division of labor which facilitates greatly the securing of food and the other necessities of life."
Of the instincts, the sexual and parental alone receive emphasis. These are not available in the development of the wider associations,
