The use of a function as a leading, means that we use it on its full capacity. Its called also intellectual function or 4th dimensional function. For understanding my point I consider useful to look the nature of the dimensionality of functions. Also it could help you to understand the types and fit yourself in the one who suits you better.
http://www.the16types.info/vbulletin...by-Irina-Eglit
http://www.wikisocion.net/en/index.p...Dimensionality
Brief explanation of dimensions:
1. Experience: experiential , subjectivity and subjective evaluation, experience in first person (sorry for repetitiveness and redundancy, I'm in lack of words).
2. Norms: What is correct or inappropriate according societal norms.
3. Situational: What is convenient and suitable on each situation. Making exceptions. Using the function on a creative (not normative) way. Freedom.
4. Time: Consistency or development over time, parameter or perception of time. Manipulation of function leading over time.
Si 4D:
1. Experience. Si being experiential Its lived subjectively through 5 senses and external stimuli, it's physical not intellectual, it's irrational (more instinctive), earthy.
It's about what suits you
personally, separated from the rest of the world.
F.e. I usually take seat when I'm in public or when I'm working if I need too. Some people, specially types with Si1D and Fe4D can look this as something wrong. I see it as natural and perfectly normal…why should I stay stand if I'm tired? Its not the most natural thing to take a sit when I'm tired? If rest of people in there wish to keep standing, I'd take a seat, I don't feel any kind of pressure to do what the rest is doing when its about my own comfort.
2. Norms.Taking care of own physical needs. Moderation. Well being. Common sense (on physical matters). Physical comfort (like in clothes and shoes, etc). Looking good or physically attractive. Fashion or traditions on clothing etc. Tend to be traditional in appearance or physical perception, aesthetics.
F.e. I don't like excessive piercings and totally dislike tattoos. I think they look ugly and I see tattoos as an unnecessarily risky and painful experience.
3. Situational. Creativity. Find solutions for particular situations. Freedom.
F.e. If I don't need to go outside the house I usually keep pajamas on. The situation doesn't require me to be on more uncomfortable clothing? Perfect! I'll use whats more comfortable. Another example, if I just need to go to the grocery store (the situation doesn't require me to go outside looking extremely presentable) I would perfectly use active wear. Why not?
On the other hand, my IEE with 1DSi, almost never use active wear even if he just need to go to the convenience store.
4. Time: Consistency or development over time, parameter or perception of time. Manipulation of function leading over time.
F.e.The things that I remember the most from past are often related to Si. How good or bad I felt on my physical of psychological being, If something was pleasurable or insufferable.
The things that I remember most of my childhood are Si things…I remember toys, I remember their colors or texutures. When I was a kid my mother used to give me milk chocolate, I still remember the taste. I remember that I liked a lot to play with plasticine and draw. If you want me to describe or imagine something, the way I'd do it is through Si. I'd describe the sounds, images, smells, sensations on a pretty vivid way, since I've a lot of resources in mind to express it in detailed way. The situations on fictional writings for example, pretty much round through sensorial experiences too.
Some of my basic explanation of Si as leading function:
-Experiential: Sensorial experience in first person. Seek of stimuli. Can I look at it? Can I touch it?
-Bodily: Taking care of own physical needs. Common sense. Moderation. Well being. Peace.
-Attuned: Comfort, usefulness, practicality. Reserve of energy and material resources; principle of minimum effort.
-Caregiving: Well meaning. Preservation. Pro Life. Adviser. Teacher. Tradition. Moderation.
Sensorial experiences is the base of the type. Si is entirely experiential. It's a function related to the senses (5 senses), it's physical not intellectual, it's irrational (more instinctive), earthy.
Pleasure seeking, comfort seeking, living through senses on an introverted way (own way), appreciation of aesthetics, internal evaluation of external stimuli, such as objects, environment (shape, light, sound, smell, touch). Aesthetics ( on philosophy).
Heightened senses: hypersensitivity to external stimuli such as loud, temperature, colors, atmosphere, touch etc. attended specially on relation of situational evaluation of comfort/discomfort. Attentive to energy level (high, low, in need of rest etc).
I don't want to suggest that my senses are more heightened than in the rest of types, its just a way to explain the concept, basically I think that I just put more attention or I'm more sensitive to that kind of things that ppl with different leading function. Deep attachment to 5 senses.
Explained? I'm slave of my own personal living experience of situations always seeking for comfortability and pleasurableness.
I'm able to sacrifice my own comfort (tbh its hard but I do it anyway ) for those I love or for a good cause (when strangers), but I'm absolutely unable and indisposed to do it for superficial or shallow goals such as ambition, fame, prestige, power or that kind of things (please notice the contradiction since pleasure seeking could be seen as being shallowness too, remember that Si is an irrational function).
This is translated in that I'll always look for the most comfortable, practical and convenient way to do things for me and others (categorically).
Taking care of practical physical matters such as clean, cook, etc. I really enjoy doing this, it can bee seen as the caregiver tendency, I enjoy this kind of physical handy work when its for loved ones, I've a feeling of purpose or usefulness when doing it for someone else. I'm always offering my help, specially when I see that is really needed.
I hope this helps.