Judith Butler's work on gender theory is heavily influenced by the post-structuralist theories of Michel Foucault and Jacques Derrida. Both Foucault and Derrida were highly critical of essentialist and universalizing theories of identity, and their work emphasizes the ways in which power operates through discursive practices and language.
Butler draws on Foucault's concept of power as a diffuse and pervasive force operating through discursive practices to argue that gender, like power, is not a fixed or essential characteristic of an individual, but rather a social construct which is continually produced and reproduced through the performance of gendered behavior.
Similarly, Derrida's deconstructionist approach to language and meaning has influenced Butler's understanding of gender as a discursive construct. Derrida argues that meaning is never fixed or stable, but is always in a state of flux and instability. Butler applies this framework to gender identity, arguing that gender is a performative act that is continually produced and reproduced through language and discourse.
The influence of Foucault and Derrida on Butler's work is profound. By drawing on their critiques of essentialism and universalizing theories of identity, Butler provides a sophisticated analysis of gender as a complex and dynamic construct that is continually produced and reproduced through social and cultural practices.