Jung and Myers both found that a well balanced type had two of the four mental functions that they were skilled at using. One was used mainly in the outer world relating to objects and people; and the other was used mainly in the inner world of thoughts and ideas. Since an Introvert also has to live in the outer world, while the Extravert has to go inside to think things over, it would seem that one of the two functions identified in one's type need to be introverted while the other needs to be extraverted.

Since we prefer to use these functions, they get used more frequently and we become more skilled at using them. Thus over time, we find that one of the mental functions becomes our strongest. It would seem that our Type is an inborn pattern. We seem to have a 'natural' skill of using our Dominant function. Since we use it well, this encourages us to practise using it more. Thus, we become the most skilled at using our Dominant function.

The strongest mental function is called the Dominant. The second strongest is called the Auxiliary. These two functions appear in the four letter designation of one's type.

Since Extraverts prefer to deal mainly with the outer world, their strongest function, or Dominant, would also be extraverted and the other mental function, the Auxiliary, would be introverted. The opposite would be true for introverts. They prefer to deal mainly with their inner world and this function, the Dominant, would be their strongest and introverted. The other function. The Auxiliary, would be used to deal with the outer world, and while the most evident to other people, it would still be not quite as strong.

Even though we do not have all four functions in our type letters, we do use them at various times. We tend to use these other two functions less frequently and we are not as skilled in using them. The third in strength is called the Tertiary function and the weakest one is called the Inferior function. It is also found that our strongest function or Dominant is the one we have the most conscious use of. The weaker our skill at using a function, the more unconscious our use of it is. Thus under stress, when our use of the Dominant hasn't worked, we often flip into using our Inferior function, (i.e. being "in-the-grip") with sometimes disastrous consequences.

So it is useful to know the hierarchy of
the functions of our type and to be able to identify it any of the other
16 types.

**Sailboat:** One way of getting a mental
picture of Extraverts having their Dominant function on the outside and
Introverts having their Dominant function on the inside, it to imagine
a sailboat. It has to have a sail to catch the wind and a keel to keep
it upright and moving in a straight line. Think of the sail as being the
extraverted function and the keel as being the introverted function.

For an extraverted boat, the sail is large
(Dominant) and the keel is small (Auxiliary). For an introverted boat,
the sail is small (Auxiliary) and the keel is large (Dominant).

With the extraverted boat, the large sail catches every little breeze and moves the boat right along. But, because of the small keel, there is not much below the surface to keep the boat stable and in a straight line. Thus, the boat moves along quickly, changing direction as the winds change.

With the introverted boat, the large keel
is more responsive to the below water currents and can stay in a straight
line longer. Since the sail is small, the boat does not move as fast. The
boat is controlled more by the underlying currents than the winds above.

**Using the Type Table to Identify Type
Dynamics**

In Extraverts the Dominant function is also the function presented to the outer world. Look at the last letter of the type to tell which function is presented to the outer world. A "J" tells us that the Judging function (T or F) is the extraverted function and is, therefore, the Dominant function. The other middle letter (S or N) is the Auxiliary and, to give balance to the type, is introverted. A "P" tells us that the Perceiving function (S or N) is the extraverted function and is, therefore, the Dominant function. The other middle letter (T or F) is the Auxiliary and, to give balance, is introverted.

For Introverts the Auxiliary function is
the one presented to the world. Their strongest function is hidden. For
introverted types, a "J" at the end of the type tells us that the function
presented to the world is a Judging function (T or F) but it is only the
Auxiliary. The other middle letter (S or N) is their Dominant. A "P" at
the end of an introverted type tells us that the Perceiving function (S
or N) is the extraverted function and is, therefore, the Auxiliary function.
The other middle letter (T or F) is the Dominant and, to give balance,
is introverted.

**The Judging Top and Bottom Rows**

Begin by looking at the top and bottom
rows of the Type Table. All eight of these types have a J at the end of
the type. This tells us that the extraverted function is the Judging function
(T or F).

**Using the Bottom Row**

ESTJ |
ESFJ |
ENFJ |
ENTJ |

Now underline the other middle letter.
This is the Auxiliary and put a small subscript _{i} beside it
to indicate that it is introverted: S_{i} or N_{i}.

**Using the Top row**

ISTJ |
ISFJ |
INFJ |
INTJ |

Then circle the other middle letter or
the Perceiving function as this is the Dominant for Introverts. Put a small
subscript _{i} beside it to indicate that this function is introverted:
S_{i} or N_{i}.

Thus for the top and bottom rows the same inner letters are introverted or extraverted. The differences is that the extraverted functions on the bottom row are also the Dominant function, while the introverted functions on the top row are the Dominant function.

**The Perceiving Middle Two Rows**

Now look at the middle two rows of the
Type Table. All of these eight types have a P at the end of the type. This
tells us that the extraverted function is the Perceiving function (S or
N).

**The Lower Middle row**

ESTP |
ESFP |
ENFP |
ENTP |

Next, on this same lower middle row, underline
the other letter (T or F) as this is the Auxiliary function. Place a small
subscript _{i} beside the letter to indicate that it is also an
introverted function: T_{i} or F_{i}.

**The Upper Middle Row**

ISTP |
ISFP |
INFP |
INTP |

Next, on this same lower middle row, circle
the other letter (T or F) as this is the Dominant function. Place a small
subscript _{i} beside the letter to indicate that it is also an
introverted function: T_{i} or F_{i}.

As an example, you should have EN_{e}__T___{i}P
and IS_{i}__F___{e}J. (The larger
letter represents the circled Dominant.)

Isabel Myers (*Gifts Differing*, 1980)
made up this little rhyme to help you remember which is the Dominant function:

**The Tertiary and Inferior Functions**

Now that we know now to identify the Dominant
and Auxiliary for any type using the type Table, let's look at how to identify
the Tertiary and the Inferior functions. If we look on Jung's Compass of
the Functions we see that the S is opposite the N, and T is opposite the
F. These are considered the polar opposites. But when we are talking about
opposites we are also identifying opposite attitudes. Thus, the polar opposite
of S_{i} is N_{e}. The polar opposite of T_{e}
is F_{i}.

For a type to have good balance there
should be an equal number of extraverted and introverted functions. Thus
if the Dominant is extraverted, and the Auxiliary is introverted, then
the Tertiary is extraverted and the Inferior is introverted. They alternate
extraversion-introversion. If the Dominant is introverted and the Auxiliary
is extraverted, then the Tertiary is Extraverted and the Inferior is introverted.
The Dominant and the Tertiary have the same attitude (extraverted or introverted),
and so do the Auxiliary and the Inferior. (Jung and Myers lumped the Auxiliary,
Tertiary and Inferior functions as all having the same attitude. Research
and practical experience would seem to favour the alternating attitudes.)

For ENFJ Type, the Dominant is F_{e},
the Auxiliary is N_{i}, the Tertiary will be the polar opposite
of Auxiliary or S_{e}, and the Inferior will be the polar opposite
of the Dominant or T_{i}.

For the ISTP Type, the Dominant is T_{i},
the Auxiliary is S_{e}, the Tertiary will be the polar opposite
of the Auxiliary or N_{i}. And the Inferior will be the polar opposite
of the Dominant or T_{e}.

Fill in the rest of the Tertiary and Inferior functions on your Type Table. Compare your answers with the table below.

ISTJDom. - S
_{i}Aux. - T
_{e}Tert. - F
_{i}Infer. - N_{e} |
ISFJDom. - S
_{i}Aux. - F
_{e}Tert. - T
_{i}Infer. - N_{e} |
INFJDom. - N
_{i}Aux. - F
_{e}Tert. - T
_{i}Infer. - S_{e} |
INTJDom. - N
_{i}Aux. - T
_{e}Tert. - F
_{i}Infer. - S_{e} |

ISTPDom. - T
_{i}Aux. - S
_{e}Tert. - N
_{i}Infer. - F_{e} |
ISFPDom. - F
_{i}Aux. - S
_{e}Tert. - N
_{i}Infer. - T_{e} |
INFPDom. - F
_{i}Aux. - N
_{e}Tert. - S
_{i}Infer. - T_{e} |
INTPDom. - T
_{i}Aux. - N
_{e}Tert. - S
_{i}Infer. - F_{e} |

ESTPDom. - S
_{e}Aux. - T
_{i}Tert. - F
_{e}Infer. - N_{i} |
ESFPDom. - S
_{e}Aux. - F
_{i}Tert. - T
_{e}Infer. - N_{i} |
ENFPDom. - N
_{e}Aux. - F
_{i}Tert. - T
_{e}Infer. - S_{i} |
ENTPDom. - N
_{e}Aux. - T
_{i}Tert. - F
_{e}Infer. - S_{i} |

ESTJDom. - T
_{e}Aux. - S
_{i}Tert. - N
_{e}Infer. - F_{i} |
ESFJDom. - F
_{e}Aux. - S
_{i}Tert. - N
_{e}Infer. - T_{i} |
ENFJDom. - F
_{e}Aux. - N
_{i}Tert. - S
_{e}Infer. - T_{i} |
ENTJDom. - T
_{e}Aux. - N
_{i}Tert. - S
_{e}Infer. - F_{i} |