Si as a Hidden Agenda (Tertiary Si) in the INTj and INFj
In Socionics, the Mobilizing Function or the Tertiary in MBTI-based models has a quality attached to it called the Hidden Agenda (HA), a term coined by Sergei Ganin. As I understand it, the Hidden Agenda isn’t synonymous with the function, but rather is a sort of complex associated with the function, not unlike the Puer Aeturnus in the Beebe Model
The following is a summation of various expressions of this complex as it relates to introverted sensing.
Ganin simply puts the Si Hidden Agenda as “to be healthy”, but how does this play out in the behavior of the INxjs? Elsewhere in Socionics theory, the dimensionality of the Mobilizing function is said to operate at a peak of personal norms with the lower level dimensionality of personal experience. The content associated with this functional perspective mostly relates to your personal code of standards experienced in a sort of "child-like" or "childish" manner. This is an area that you truly want to be more proficient in, but you don’t interpret the information concerning this area of life accurately, so you tend to look to others to model your behavior upon them, and for direct assistance in handling this part of life. Also implicit in the term Hidden Agenda is that it is something that is hidden about yourself from others and somewhat hidden from your conscious awareness.
The definition of “To be healthy” for Si HA does not literally mean what it actually means to people of INxj types who are consciously aware of this desire in themselves. “To be healthy” is characterized by a warped, uneven, inconsistent interpretation of what this means and how to achieve it. A common characteristic of lower level Si is a poor body image or disconnect with bodily perceptions. There is often over-compensation in all matters related to this function as well. The first aspect that we can consider here is that HA Si looks to others to model and imitate other’s behavior and appearance to a certain degree, but it just can’t. INxjs are often not imposing of physical built (with some exceptions) and may feel inadequate due to this, and wish to bulk up (men) or slim down (women) by exercising and lifting weights. Another problem arises here is that they feel awkward, uncomfortable, and sometimes down right horrified by the prospect of stepping into the foreign area of a gym, having to use new exercise machines without anyone's instruction or help, and exposing themselves and their body to the on-look of others. This hits them in several ways from an Si perspective. First there is the issue of having to handle and organize this new space and objects in it. Then there is the issue of doing it in an unfamiliar environment, and the difficulty of building and sticking to a routine despite feeling inconvenienced and awkward. An INxj is more likely to buy some dumb-bells from a self-checkout line and find a work-out routine from YouTube videos and do it in the privacy of their own home, or go out jogging in the mornings when everyone is asleep, until they give up a few weeks later still feeling a disconnect from their bodies and the Si discomfort that the exercise has caused them.
In the matter of appearance, there is this odd contradiction here as both types are fiercely independent when it comes to their dominant Ti or Fi, yet they have a desire to blend in and assimilate in sensory respects with their appearance. They may take on the exercise methods developed and recommended by others to them. They may act like a chameleon when it comes to appearance, mimicking the way others dress, maybe trying to be a little more put together than quite a few other types. It is as if they are hyper-conscious of dressing appropriately for how they wish others to see them and what function they need to play. Developed tertiary Si types would be mortified by wearing sweat pants in public or a short-sleeve button-up shirt with a tie, as they were once told that it makes them look like Dwight Shrute (under-developed types may not have this awareness, but I think that is more pertinent to 1D Si of ENxps). Maybe it is a strict personal code that you never wear white socks with black shoes, because someone made fun of you for doing so once years ago. All of this is ultimately motivated by one’s inferior function.
Keeping up with the times and current events may become a matter of importance for these types. For example, Keeping up with the Kardashians or Game of Thrones may not particularly interest them in itself, but the desire to keep up with and understand culture and recent social developments is. They do not want to be left out of the "stream of information" as well as being able to follow along and feel connected to sensory impressions of the outside world. They may also want to know the “places to be” in town, such as the best bars and clubs and restaurants, even if they don't have much desire to sit around there themselves. This comes back to a desire for an awareness of their environment and mirroring the perceptions of others.
INxjs may also have an odd relationship with their sense of health. They may develop certain habits of washing hands religiously, brushing teeth with the most advanced toothbrush known to man (that is also the most practical), or may form an aversion to certain additives, while ignoring others. The latter may be the sort of thinking that I may smoke a pack a day and never exercise, but at least I don’t put Splenda and soy in my seven cups of coffee. That shit will kill you. Did you know that Splenda was originally developed as a pesticide and soy can make a man grow breasts? How could you put that into your body? This is the irrational side of an otherwise rational person. These quirks stand out like a sore thumb, especially to a higher level Si user.