There are so many aspects that need to be considered it escapes the imagination. A new approach in the engineering field is called a System of Systems. This is used to develop an approach based upon complicated systems and how they interact with one another. I am convinced that the development of Asimov's Psychohistory will be done in a similar fashion. When looking at the number of different disciplines needed to describe the human phenomenon, no single approach is adequate. Just asking the question about human behavior, whether it is learned or biological (the famous "nature versus nurture" debate) implies how complicated it can be. Can a Psychohistorian dare to ignore how people behave on an individual level when attempting an approach that covers many millions?