Durkheim proposed rules for distinguishing between normal and pathological social facts. Rule 1 states that a social fact is normal if it is present in most societies of that type at a given stage of development. Rule 2 is that a social fact's normality can be verified by showing it is tied to general societal conditions. Rule 3 states that verification of normality is needed for societies not fully evolved. Pathological facts harm solidarity while normal facts are integral to society. However, normality is relative, as what is normal can differ between groups.