The challenge of James Joyce’s final work, Finnegans Wake, is an ethical one, and one whose implications extend far beyond the boundaries of that particular book. Joyce’s dismantling of language is too often dismissed as either a meaningless experiment or else a superficial attribute beneath which we can somehow postulate a “truer” writing that is perfectly straightforward. I argue that taking seriously the strangeness of Finnegans Wake leads to an interaction with alterity. Confronting us with a writing that we can only assimilate insofar as we do violence to its illegibility, Joyce drives a wedge between knowledge and mastery. He forces us to rethink our own position as readers. Ultimately, the Wake requires us to develop modes of interpretation that acknowledge their own status as necessarily incomplete, and that resemble what post-structuralist ethics conceptualises as the questioning of the self in an encounter with the other. This is an exemplification – not a negation – of the workings of knowledge production in virtually all linguistic codes. To examine the hermeneutic critique that Joyce effectively offers, I draw on Derrida’s analyses of the sign and of hospitality, as well as on Lacan’s theorising of the subject’s implication in a symbolic system whose descriptive powers are constitutively insufficient. I conclude that the language (or non-language) of Finnegans Wake represents Joyce’s criticism of the ideal of univocal expression, whilst it also puts to work the very mechanisms that render absolute clarity impossible, achieving a poetics of plurality and of hospitality towards the undecidable. This implementation of multiple meanings has an intrinsic political and ethical dimension, promoting diversity and tolerance.