Near the beginning of the Cratylus (385e-387d) Plato's Socrates argues, against his friend Hermogenes, that the standards of correctness for our use of names in speech are in no way up to us. Yet this conclusion should strike us, at least initially, as bizarre. After all, how could it not be up to us whether to call our children by the names of our parents, or whether to call dogs "dogs"? My aim in this paper will be to show that, although Plato's argument does not succeed in establishing this apparently bizarre conclusion, it may well succeed in establishing an equally momentous conclusion: that the standards of correctness for our use of concepts in thought are in no way up to us.