David Hume more thoroughly explained the usefulness of understanding human nature. “It is evident that all the sciences have a relation, greater or less, to human nature, and that however wide any of them may seem to run from it, they still return back by one passage or another. Even mathematics, natural philosophy, and natural religion are in some measure dependent on the science of man, since they lie under the cognizance of men and are judged of by their powers and faculties. It is impossible to tell what changes and improvements we might make in these sciences were we thoroughly acquainted with the extent and force of human understanding and could explain the nature of the ideas we employ and of the operations we perform in our reasonings…
“Here then, is the only expedient from which we can hope for success in our philosophical researches: To leave the tedious lingering method which we have hitherto followed, and instead of taking now and then a castle or village on the frontier, to march up directly to the capital or center of these sciences, to human nature itself, which being once masters of we may everywhere else hope for an easy victory. From this station, we may extend our conquest all over those sciences which more intimately concern human life, and may afterwards proceed at leisure to discover more fully those which are the objects of poor curiosity” (Hume).
The usefulness of Five Categories Theory is universal across disciplines. With Five Categories Theory, we are finally masters of human nature. Here is a quick list of subjects directly improved by understanding human nature:
Rhetoric, persuasion, advertising, negotiation, leadership & management… involve convincing and motivating people.
All arts -- Visual art, music, storytelling (including writing, directing, acting)… art reflects the human experience and its value reflects its ability to elicit emotions.
Politics, leadership & management, parenting & childcare, psychiatry, social work… require one to understand and help others with emotional / motivational problems.
Psychology, history, anthropology, sociology, theology, ethics, political theory, linguistics… study systems which emerge from human behavior.
And, as Hume notes, all subjects are improved by understanding human nature, as “they lie under the cognizance of men and are judged of by their powers and faculties.”