I'm referring to the theory of (classsic) Socionics, of course.
Obviously there are going to be many different aspects to the subject of Socionics, but I'm talking about the theory itself. It's a very intuitive theory, but it's also largely Ti in nature.
This is an example of a Ti system:
- There are three components of information (internal vs. external, etc.). There are eight combinations of these components, and these combinations of components are called information aspects.
There are two types of information aspects, rational and irrational, and there are two axes of each. This makes four axes, two rational and two irrational. Everyone values one rational axes and one irrational axes. There are 4 combinations of valued axes, and these combinations are called quadras.
Each quadra has fours types, each led by one of the information aspects it values. The types are grouped into dual pairs based on whether their leading function is rational or irrational.
All types are divided into introversion or extroversion based on their leading function.
The rest of the theory revolved around model A (or another model), which is a set of functions. Each type has a different arrangement of functions, and types interact with each other in different ways based on these arrangements. These interactions are called intertype relations.
Of course, there are many other Ti systems in Socionics, more than I feel like getting into right now.