Human Nature & Continuity

"If 'human nature' does not exist, other than as a specific, basic biological structure that means one human can only reproduce in conjunction with another, then what authority can anybody or any human document that belongs to another time or place have? If human nature is really a construct of the particulars of a specific historical, geographical, and cultural context, it is not immediately obvious that, say, a document produced in Constantinople near the end of the fourth century can have any relevance to people living in London or New York at the start of the twenty-first. For historical documents to speak beyond their own time there has to be some kind of fundamental continuity between their form and content and the present age" (Carl R. Trueman, The Creedal Imperative, 30-31).