Why is whether or not human nature exists an important question to answer?

Early in his essay, Toward A Universal Ethics, Michael Gazzaniga considers whether human nature exists. He quotes authorities who deny that there are instincts or anything like a human nature and assert that the brain has no predisposition but is adaptable to “a full range of behaviors.” Argue a case FOR human nature. Consider the role recent studies of brain physiology might play in this debate. Why is whether or not human nature exists an important question to answer?