On muteness:

“The differend demands a rigorous listening-not because of some a priori rule which says I must do the other’s bidding, but precisely due to the absence of a priori rules, to the sui generis nature of the encounter Every differend has never happened before-it is always happening for the first time, and thus requires an openness to every possible way of linking onto the phrases produced. “Phrase” here does not necessarily mean linguistic phrases, but it does mean “utterance” produced by a semiotic agent or whatever is taken to be a semiotic agent by the rules of the language game. In other words, in some contexts a lighting bolt might be a phrase (as when a mystic believes herself to be peaking to God, who then sends down a lightning bolt in response), whereas in others it won’t be (as in a meteorological di course). Silence is a phrase when someone chooses to withhold or not speak. Thu , for our purposes, everything depends upon showing that nonhumans can be, and are, semiotic agents and maintaining a context in which what they produce counts as utterances in spite of the fact that these utterance will ncesarily be, for lack of a better term, different. In other words, this model of democratic being-with requires that we figure the other as capable of meaningful utterances even as we are unable to understand these utterances.

Cary Wolfe’s critique of Lyotard’s notion of the differend centers precisely on the notion of agency and its humanistic entanglements. Because the differend takes place between agents of phrases, it is not the best model for understanding our differences from animals when animals are “mute” as a matter of course, not agentially. The animal’s silence is not a phrase and so not a proper silence, “it is not a withholding, and thus does not express the ethical imperative of dissensus and the diflerend” (Wolfe 2003:59). Because the animal cannot be said to be the agent of its utterances in the same way as the human, Wolfe argues, this fundamentally undermines the effectiveness of the differend schema for a multispecies theory of justice. Lyotard’s humanist commitments sneak in “in the taken-for-granted muteness of the animal, which, crucially, can never be a withholding” (Wolfe 2003:62). However, apart from what Lyotard may or may not have written about the animal, it is important to examine what role agency could possibly play in a philosophy that begins from the condition of a relation of not-understanding the other. What does it mean to identify a being as a semiotic agent-or not-in conditions of not-understanding?”

From, Beyond the Cyborg: Adventures with Donna Haraway