A Serialization of the Characters and their Influence on Macbeth Essay submitted by davo One of the most commonly debated issues concerning morality is the concept of nature versus nurture. Which is more integral to one’s behavior: the inborn qualities or the influences of life on the individual? Mark Twain, in his essay entitled "What Is Man?" describes humankind this way: Man the machine--man the impersonal engine. Whatsoever a man is, is due to his MAKE, and to the INFLUENCES brought to bear upon it by his heredities, his habitat, his associations. He is moved, directed, COMMANDED, by EXTERIOR influenc