As phrased by José Casanova, this "core and the central thesis of the theory of secularization is the conceptualization of the process of societal modernization as a process of functional differentiation and emancipation of the secular spheres—primarily the state, the economy, and science—from the religious sphere and the concomitant differentiation and specialization of religion within its own newly found religious sphere".Casanova also describes this as the theory of "privatization" of religion, which he partially criticizes.Smith believes intellectuals have an inherent tendency to be hostile to their native cultures, causing them to embrace secularism.
As the responsibility for education has moved from the family and community to the state, two consequences have arisen: A major issue in the study of secularization is the extent to which certain trends such as decreased attendance at places of worship indicate a decrease in religiosity or simply a privatization of religious belief, where religious beliefs no longer play a dominant role in public life or in other aspects of decision making.
The issue of secularization is discussed in various religious traditions.
Considerations of both tolerance and autonomy are relevant to any secular state. John Sommerville (1998) outlined six uses of the term secularization in the scientific literature.
The first five are more along the lines of 'definitions' while the sixth is more of a 'clarification of use': As studied by sociologists, one of the major themes of secularization is that of "differentiation"—i.e., the tendency for areas of life to become more distinct and specialized as a society becomes modernized.
is the transformation of a society from close identification with religious values and institutions toward nonreligious values and secular institutions.
The secularization thesis refers to the belief that as societies progress, particularly through modernization and rationalization, religion loses its authority in all aspects of social life and governance.
Social theorists such as Karl Marx, Sigmund Freud, Max Weber, and Émile Durkheim, postulated that the modernization of society would include a decline in levels of religiosity.
Study of this process seeks to determine the manner in which, or extent to which religious creeds, practices and institutions are losing social significance.
In secularized societies faith lacks cultural authority, and religious organizations have little social power.
Secularization has many levels of meaning, both as a theory and a historical process.