Abstract
Definitions of religion diverge considerably from those which see religion as a particular ideology to those which, on the contrary, see ideologies as “secular” (or “civil”) religions. Historically, they have ranged from a tendancy to reductionism, typical of positivism and marxism, to quite the reverse, as can be seen in “ultimate” definitions, influenced by theology. If only to differentiate the “secular” religions from the others, we do not see how “substantive” criteria can be dispensed with. At the end of the analysis, a plural and heuristic approach to definitions is put forward.
