The Greek writers, the Hebrews before them, the founder of Christianity made references to the likenesses between human society and plant and animal life. Mankind has often been compared to a tree or a plant with its manifold, evolving branches and fruit. Spencer’s famous organic analogies were preceded by the studies of biologists, such as Lamarck and Darwin. Lamarck (1744–1829) argued that by activity and use man could develop traits which would be transmitted by inheritance. Although this theory has been undermined by Weismann, it served as a basis for the further study of the biological laws of human evolution. The thought of Charles Darwin (1809–1882) upon the nature of evolution was stimulated in part by Malthus’ doctrine of surplus population and the consequent struggle for existence. He also based his ideas on the Lamarckian theory of transmission of acquired characters. He developed the concepts of the prodigality of nature and the struggle for existence, which led to the resultant concept of natural selection and survival of the fittest. The process of natural selection accounts for the instincts, imitation, imagination, reason as well as for self-consciousness, and the esthetic and religious impulses. In this way man, according to the Darwinian formula, has ascended by stages from the lower orders of life. The fittest to survive, concluded Darwin, are those individuals who are best fitted to meet the conditions of their environment. If the environment be competitive, savage, brutal, then the fittest will be the strongest physically and the most vicious. If the environment be co-operative, then the fittest will be the individuals who co-operate best. With the development of intelligence and sagacity in early human society, individuals otherwise cruel learned to co-operate. A tribe of co-operating individuals would be victorious in a conflict with a tribe of non-co-operating members. Thus co-operation and a co-operating environment themselves are the result of natural selection. Unfortunately, Darwin’s concept of natural selection has been grossly distorted. Upon this misapprehension, a doctrine of “social Darwinism” has gained recognition. According to this false interpretation of Darwinism, the tooth and fang struggle for existence among animals is the normal procedure among human beings. The most brutal, cruel, and shrewd men are “fitted” to survive in an environment of physical and mental competition. Likewise, the nations which can marshal together the most powerful armies and navies are the “fittest” to survive in a world where each nation is accountable unto itself alone. Thus, it is seen that human society is simply an extension of the animal society and that the fundamental law of social progress is the law of force and might, first physical, and then physical and psychical.