Chapter One

Introduction

The concept of Psychological Type harkens back to as far as the Ancient Greeks (who codified ideas of the Ancient Sumerians) when the cause of differing personalities was thought to be caused by varying levels and ratios of the vital fluids of the human body (called "humors"), which were blood, yellow bile, black bile, and phlegm (the four temperament theory).

The four temperament theory suggests that there are four fundamental personality types: sanguine, choleric, melancholic, and phlegmatic.  This theory stayed dominant in proto psychology until nearly the 20th century, and still exists today (with new terms and causes). 

Then along came a man named Freud.  Freud's theories were revolutionary for the times, and he attracted many critics and protoges, sometimes found in the same person.  Two of those students were Adler (famous for creating the Inferiority Complex) and Carl Jung, who became his closest confidant and later his bittermost rival.

After many years of collaboration, Freud, Adler, and Jung all parted ways.  Jung had two primary criticisms of Freud's and Adler's theories, and these critiques were two sides of the same coin - in Freud, Jung found the theory overly reliant on outside influences, or was extraverted; in Adler, he found his theory overly reliant on internal structures, or was introverted.  Together, however, introverted and extraverted sources seemed to satisfy Jung's hypothesis, initially. 

That satisfaction was short-lived.  There were too many variations amongst people he observed to be Introverted and Extraverted for it to be the complete theory, despite that there were distinct divisions between the "I"s and the "E"s.  There had to be something more, and that's where he recognized the next piece in his developing Typology.

In what some would say was a precurser to cognitive psychology, Jung observed that people all do two things with information - They Perceive information and they make Judgments about said information, and that some preferred one over the other, and the sources of those perceptions and judgments also had their preferences - the introvered and extraverted spheres of their lives.  At this point, he had four distinct Types, based on their most preferred mental functions - Introvered Perception, Extraverted Perception, Introverted Judgment, and Extraverted Judgment.

Again, he believed that he had a complete model for his typology.  Each of the four were consistently distinct from the other, and the vast majority of the people he observed fit within one of the four classifications.  And yet again, it was not enough to account for the variations found within each Typology.  There had to be more granular way to distinguish them - meaning more divisions.  These next divisions he observed would flesh out the underlying structure, and pave the way to applying them to a more complete theory.

This concludes the Chapter One introduction of Typology.  Chapter Two will reveal the final aspects of the Typological structure, and introduce two new people into this family tree of Psychological Type who would move it from Theory to Application.