Functional Analysis

Carl Jung developed psychological types based on the four functions (Feeling, Thinking, iNtuition and Sensing) and the two attitudes (Extraversion and Introversion). (There is, in my experience, a good deal of confusion, especially among those without some grounding in psychological type, about the nature of these functions and attitudes. The words don't necessarily mean what we expect them to mean, and caution should be used in applying common usage to these terms if this system is to be of value in the understanding of basic temperaments.)

In this system there are eight basic types, each designated by its dominant (defining, controlling, pre-eminent) function:

Symbol	Jungian Type	Myers-Briggs Types
Fe	Extraverted Feeling	ESFJ    ENFJ
Fi	Introverted Feeling	ISFP     INFP
Ne	Extraverted Intuition	ENFP    ENTP
Ni	Introverted Intuition	INFJ     INTJ
Se	Extraverted Sensing	ESFP    ESTP
Si	Introverted Sensing	ISFJ     ISTJ
Te	Extraverted Thinking	ESTJ    ENTJ
Ti	Introverted Thinking	ISTP     INTP

Jung developed these types within a mental illness model. He spoke of functions being dominant, auxiliary, tertiary and inferior. The 16 types popularized through the MBTI reflect each of Jung's eight types subdivided by auxiliary (secondary) functions.

Of the four functions, two (Feeling and Thinking) are the rational, or deciding, functions. The other two (Sensing and iNtuition) are the irrational (non-conclusive/perceiving) functions. If an individual has a dominant rational function, one of the irrational functions is always auxiliary. Likewise, dominant N (irrational) would have an F or T (rational) function. Third and fourth functions are mirror-images of the first and second. For example, if Sensing is first and Thinking is secondary, Feeling (the opposite of Thinking) must be tertiary, and iNtuition (Sensing's opposite) would be fourth.

There are two schools of thought concerning the attitude, or direction of energy flow, of each function within a given type. Some believe that if the dominant function is Introverted, the other three will be Extraverted; likewise, an Extravert's non-dominant functions are all Introverted. Others think that the attitude alternates from first to fourth position as I/E/I/E for Introverts and E/I/E/I for Extraverts. The functional analyses in our profiles follow the latter alternating pattern.

In summary, the sixteen types in four-function terminology are:

	ESFJ	ISFJ	ESTJ	ISTJ		ENFJ	INFJ	ENFP	INFP
Dominant	Fe	Si	Te	Si		Fe	Ni	Ne	Fi
Auxiliary	Si	Fe	Si	Te		Ni	Fe	Fi	Ne
Tertiary	Ne	Ti	Ne	Fi		Se	Ti	Te	Si
Inferior	Ti	Ne	Fi	Ne		Ti	Se	Si	Te

	ESFP	ISFP	ESTP	ISTP		ENTJ	INTJ	ENTP	INTP
Dominant	Se	Fi	Se	Ti		Te	Ni	Ne	Ti
Auxiliary	Fi	Se	Ti	Se		Ni	Te	Ti	Ne
Tertiary	Te	Ni	Fe	Ni		Se	Fi	Fe	Si
Inferior	Ni	Te	Ni	Fe		Fi	Se	Si	Fe

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