Conversation so far:
What did he do in 1988?
In this essay, Judith Butler proposes her theory of gender performativity, which would be later taken up in 1990 throughout her work, Gender Trouble.
what was her theory about?
that both phenomenology and feminism ground their theories in "lived experience".

Question: what is lived experience?
Self-contained rewrite: What is lived experience that both phenomenology and feminism ground their theories in?