 For Sanches names are arbitrary, and therefore they can in no way define “the nature of things”, or their essences. Now, if you argue that you can use definitions to demonstrate the nature of a thing, “then show me one such”, responds Sanches. In a manner that recalls some twentieth century philosophers of language, Sanches questions whether words like Being, Substance, and Essence mean anything at all beyond the circularity of their definitions, and whether we even understand what we mean when we employ them. For example, with respect to the notion of Being, he writes: 