Laclau and Mouffe tie their concept

Laclau and Mouffe tie their concept of discourse to Lacan’s psychoanalytic theory. In their account, the subject desires ‘full-ness’, conceives as psychological stability based on integrating the self with the other. Yet, this desire for fullness is thwarted by a primordial ‘lack’ since there is always doubt whether the ‘other’ has recognized the self. This lack means the other gets blamed for blocked identity. A quasi-structural antagonism between self and other is thus integral to identity formation.
According to Laclau and mouffe, the same quasi-structural logic applies to discourses. On the one hand, discourses exhibit a logic of equivalence: they try to integrate many views into one worldview, stressing commonalities in contrast to another. On the other hand, discourses exhibit a logic of difference: they are constituted by an antagonism to the other – an antagonism that always limits the extent to which they can achieve integration. The interplay between equivalence and difference in discourses sets up hegemonic struggles.