If you take into account that within the theory, Fi is largely sourced from "primordial images" which come from the "collective unconscious", then it's arguably more "universal" than Fe is. Fe is far more contextual - in line with the values of the family, culture, social clique, country, etc.
Fi is about fundamental principles; it is abstract, basic concepts cutting to the heart of why something is important or necessary for humanity. It is subjective in that it focuses on the inner underlying image - or the the universal principle - in its most pure, simple form, so as to keep the external from corrupting it (because the masses are known to become unreasonable mobs). In this sense, Fi is striving to maintain a consistency so as to protect the universal nature of these ideas or images, and that's why it resists degradation to mere social rules - it resists "the object" in that sense.
Fi seeks to protect, perfect & simply
understand these moral ideals by keeping them abstract (in that pre-verbal, undefined form). Fe seeks to define them to make them viable; that's all well & good, but not when the context changes & the rule is no long applicable. Frankly, this is why Fi types are more flexible in general; they see the underlying principle & how it can be applied in many ways across contexts. It's often the very same moral at root across these contexts though. Fi does, however, reason on these concepts & do much of its own interpretation, which certainly makes it subjective. This is why the focus is on adapting these concepts to the needs of individuals (not making blanket rules). So what's right for you is right for me, but that may still manifest very differently because we are two different "contexts", even as the core principle is very much the same.
To the Fi type, Fe can't exist without Fi; Fe is just a manifestation of Fi applied to a specific context. (Of course, this how the mind of the introvert works; reality is ideas & thoughts & concepts). Ideally, Fe + Fi work together, in the interests of the individual & the group, as neither is fully satisfied when the other is lacking.
"Treat others the way you'd want to be treated" is fine to Fi, with the caveat of "remembering that they are not you & may want to be treated differently than you'd like to be treated". Because the principle behind that statement is NOT saying you should assume everyone feels as you do. Treating someone the way you want to be treated means considering their needs/wants as you'd want them to consider yours, not assuming their needs/wants are the same as yours.
Jung's definition of Image & Primordial Image said:
When I speak of "image" in this book, I do not mean the psychic reflection of an external object, but....a figure of fancy. This image... appears more or less abruptly in consciousness, somewhat in the manner of a vision... The image has the psychological character of a fantasy idea....The inner image is a complex structure made up of the most varied material from the most varied sources.
I call the image primordial when it possess an archaic character.... It then expresses material primarily derived from the collective unconscious and indicates at the same time that the factors influencing the conscious situation of the moment are collective rather than personal.
The primordial image is a precursor of the idea and its matrix. By detaching it from concretism peculiar & necessary to the primordial image, reason develops into a concept; ie. an idea which differs from all other concepts in that it is not a datum of experience, but is actually the underlying principle of all experience.
Jung's definition of Collective said:
I term collective all psychic contents that belong not to one individual, but to many, ie., to a society or people, or to mankind in general. Such contents are what Levy-Bruhl calls the"representations collectives" of primitives, as well as general concepts of justice, the state, religion, science, etc, current among civilized man. It is not only concepts and ways of looking at things, however, that must be termed collective, but also feelings. Among primitives, representations collectives are at the same time collective feelings, as Levy-Bruhl has shown. Because of this collective feeling value, he calls the representations collectives "mystical", since they are not merely intellectual, but emotional. Among civilized peoples, too, certain collective ideas - God, justice, fatherland, etc - are bound up with collective feelings. This collective quality adheres not only to particular psychic elements or contents, but to whole functions.
Fi said:
Its aim is not to adjust itself to the object, but to subordinate it in an unconscious effort to realize the underlying images.
It is continually seeking an image which has no existence in reality, but which it has seen in a kind of vision.
The primordial images are, of course, just as much ideas as feelings. Fundamental ideas, ideas like God, freedom, and immortality, are just as much feeling-values as they are significant ideas.
