Sextus Empiricus Pyrrhoniae Hypotyposes 2.16.207

[207] So then, without preliminary, if, on the one hand, the man who knows not the object of definition is unable to define the object unknown to him, while, on the other hand, the man who knows and proceeds to define has not apprehended the object from its definition but has put together his definition to fit the object already apprehended, then the definition is not necessary for the apprehension of objects. And since, if we propose to define absolutely all things, we shall define nothing, because of the regress ad infinitum; while if we allow that some things are apprehended even without definitions, we are declaring that definitions are not necessary for apprehension, seeing that we are able to apprehend all things apart from definitions in the same way as the undefined objects were apprehended,