Following the initiative of Abū Hāshim al-Jubbā'ī, the Baṣran Mu'tazilites rejected the view of language, dominant till then in the Islamic milieu, according to which humanity had received it by way of divine revelation, and defended the position that language had arisen by means of a human convention. On the Baṣran understanding of this convention, the connection between words and things was effected by means of a momentous act of intention to assign a name, which was revealed to another through a bodily gesture or act of pointing. In considering the signifying powers of this bodily manifestation of intention, I discuss two points of difficulty, one internal and one external (grounded in Wittgenstein's critical framework) which beset the Baṣran Mu'tazilite account.