Roland Barthes's approach to sociology was initially inspired by existentialism, Marxism, and the linguistics of Saussure; at the same time it developed a very personal preoccupation with the power of language to both liberate and oppress. In Writing Degree Zero he examines how literary forms assert or challenge social allegiances. In Mythologies he studies the way in which photographical or textual messages impart an air of naturalness to a view of the world that in fact supports French capitalism and imperialism. His later writings emphasize, by contrast, how the discourse of theory can oppress rather than liberating and he comes to view the sociological perspective as inimical to the personal and interpersonal values he seeks to affirm.