Rules of sociological methods address issues that relate to the difference in human behaviors. It states that, some behaviors are common to everybody and are likely to be displayed by everybody even if in miniature ways, but some behaviors are part of entire humanity. Moreover, the book spells out that the state of health or sickness varies within the same species, but relates to age. In relation to crime, the contributors have the feeling that crime is essential to human evolution since the existence of crime, force people to change their social norm. Therefore, there are numerous rules that sociologist have developed classifying and linking people with similar social life.
Social facts of social species are usually described as either normal or abnormal. These rules aim at relating social phenomena and the effects of social life. Nonetheless, its experimenters could not control social phenomena thus adopted the use of comparative sociology methods since it related well to the principle of causality. This method has the implication that every effect has a cause and always corresponds to the same effect. For instance, suicide is considered to result from different causes since, in reality, there are different types of suicide. This can also be related to crime. However, not all the sociological, comparative method procedures possess equal power of proof. For instance, residues method does not constitute reasoning thus cannot be applied in the study of social phenomena. In addition, it cannot be used in evaluating all the effects of all causes, since it is too complex. Therefore, a social aspect of life can only be analyzed using a method that provides more effects to the referred cause.