 Human nature so conceived may be described metaphorically as being like a plain block of wood (pu) that has not been carved into a functional or ornamental object, or it may be articulated self-referentially as what is “genuine” or “authentic” (zhen) of the person (e.g., commentary to Laozi 16 and 28). However, these remain expedient markers pointing to the truth of ziran, of what is “self-so,” understood as being rooted in a conceptually necessary ontological foundation that the ancient sages aptly described as Dao.