  First, at the level of primary sounds, it is agreed that the word for ‘hardness’, sklêrotês, contains both a hardness sound, R, and a softness sound, L. (We are permitted to assume that all the other sounds in it are neutral in this regard.) How then do people succeed in understanding its meaning correctly? Thanks to convention, is the unfortunate answer to which Cratylus commits himself, thus conceding to Hermogenes far more than he ever intended to (434e–435b). Second, Socrates points out that the names of numbers will be impossible to explain without including an element of convention.