Two Birds in a Tree: Glossary: Auxiliary function

The second strongest and most developed of the four psychological functions. One function will always be the strongest; this is called the "primary function." In addition, there's a second function that will also generally be under the conscious control of the ego. This second function is never the opposite of the primary function; e.g. those whose feeling function is superior can have either intuition or sensation as their auxiliary function, but never the thinking function.(1)

While this second function is never quite as firmly under our control as our dominant function, it is still fairly well adapted to the external world. In an extrovert this secondary function supports the primary function, assisting it as the ego strives to prosper in the world. If the primary function is "rational" (thinking or feeling), the ego uses the auxiliary function to get information that the primary function then judges. If the primary function is "irrational" (intuition or sensation), then the auxiliary function gives the ego a way to judge the information that it takes in.

In introverts, however, the auxiliary function works differently. Extroverts turn their primary function towards the external world; when you meet an extrovert you can quickly make out their primary function because that is the one with which they will greet you. Introverts turn their primary function inwards; the function they turn to the world is actually their auxiliary function. For example, if you meet an extroverted feeling type who secondarily relies on their sensation, you will see a feeling type. But if you meet an introverted feeling/sensation type, you will initially perceive their auxiliary function, sensation. This is because introverts rely on their auxiliary function to get through life. Introverts hide their primary function (in this case, feeling), unless they get to know you well. This makes introverts seem a bit awkward because they're generally using their second best function when dealing with the world.(2)

The auxiliary function as the "growth state"(2)

A useful way of thinking about the various functions is to imagine the four functions as passengers in a car. The first function would be the Driver; the second, in the seat next to the driver, is the Co-Pilot (or the auxiliary function). The two other functions are the two kids in the back seats, the tertiary or "10 Year Old" function and the inferior or "3 Year Old" function. The car looks something like this:

(from Personality Hacker)

The auxiliary function, or the Co-Pilot in the Car Model, is of huge importance; it's what Personality Hacker calls our "growth state." Time and effort spent developing this particular function takes us to a whole new level. This is because it makes up for the weaknesses of our Driver function; it allows us to introvert if our Driver is extroverted (and vice versa), and to make decisions if our Driver is a perceiving function (and vice versa). It also stops us from running to our 10 Year Old process and act out the worst aspects of that function in an effort to defend ourselves, which we often do precisely because we don't want to do the difficult task of living in our Co-Pilot.

The Co-Pilot is always hard. We're not used to living in that world (introverted or extroverted). It's scary and intimidating, and difficult... but it's the exact thing we need to do if we want to accomplish great things. As an example, my Driver is introverted thinking. It's very easy for me to run to my 10 Year Old function of introverted sensation when the going gets tough; when I'm hurt, or especially when I'm scared to go into the outside world. What this looks like is staying at home, where I feel safe and comfortable. If someone of my type (INTP) does this too much, their world becomes very small. They may even become shut-ins, unable to bring themselves to leave the safety of their homes. Even worse, if I do this too much then it will begin warping even my primary function; I will no longer be able to think clearly, my ideas about things will probably be wrong.

The antidote to this is my Co-Pilot, extroverted intuition (or Exploration). It's tends to be scary and difficult for me to do but it's precisely what INTPs need. Going to my Exploration function gets me out of the house. It allows me to test my theories, to put them into practice in the real world. If I keep all the cool ideas to myself, what good are they? Going to my Co-Pilot lets me actually make a difference in the world.

Every type does something similar when they hide in their 10 Year Old function. Every type will be well served by working on their Co-Pilot. The good thing is that this second function is actually something that we can get quite good at; believe it or not, it's actually an area of natural talent. After spending some time developing our Co-Pilot, it becomes a part of our personality. It may always require a little more effort than our Driver; while the Driver is our area of unconscious competence, our Co-Pilot is our area of conscious competence. Energy spent here, though, is some of the highest leveraged work we can do. It pushes us to develop the weaker parts of ourselves. It makes us a more complete person.

For a more in-depth look at your type, and your Co-Pilot function, check out Personality Hacker.

Absolute sovereignty always belongs, empirically, to one function alone, and can belong only to one function, because the equally independent intervention of another function would necessarily produce a different orientation which, partially at least, would contradict the first. But since it is a vital condition for the conscious process of adaptation always to have clear and unambiguous aims, the presence of a second function of equal power is naturally ruled out. This other function, therefore, can have only a secondary importance… Its secondary importance is due to the fact that it is not, like the primary function… an absolutely reliable and decisive factor, but comes into play more as an auxiliary or complementary function.

- "General Description of the Types," CW 6, par. 667.

I have frequently observed how an analyst, confronted with a terrific thinking type, for instance, will do his utmost to develop the feeling function directly out of the unconscious. Such an attempt is foredoomed to failure, because it involves too great a violation of the conscious standpoint. Should the violation nevertheless be successful, a really compulsive dependence of the patient on the analyst ensues, a transference that can only be brutally terminated, because, having been left without a standpoint, the patient has made his standpoint the analyst… (Therefore) in order to cushion the impact of the unconscious, an irrational type needs a stronger development of the rational auxiliary function present in consciousness (and vice versa).

- “General Description of the Types,” CW 6, par. 670

The process of working through the auxiliary functions goes on somewhat as follows: Suppose you have sensation strongly developed but are not fanatical about it. Then you can admit about every situation a certain aura of possibilities; that is to say, you permit an intuitive element to come in. Sensation as an auxiliary function would allow intuition to exist. But inasmuch as sensation (in the example) is a partisan of the intellect, intuition sides with the feeling, here the inferior function. Therefore the intellect will not agree with intuition, in this case, and will vote for its exclusion. Intellect will not hold together sensation and intuition, rather it will separate them. Such a destructive attempt will be checked by feeling, which backs up intuition.

Looking at it the other way around, if you are an intuitive type, you can’t get to your sensations directly. They are full of monsters, and so you have to go by way of your intellect or feeling, whichever is the auxiliary in the conscious. It needs very cool reasoning for such a man to keep himself down to reality. To sum up then, the way is from the superior to the auxiliary, from the latter to the function opposite to the auxiliary. Usually this ﬁrst conﬂict that is aroused between the auxiliary function in the conscious and its opposite function in the unconscious is the ﬁght that takes place in analysis. This may be called the preliminary conﬂict. The knock-down battle between the superior and inferior functions only takes place in life.