Introversion and Extroversion:

Jung can be accredited with the theories behind ‘Introversion and Extroversion’. He believed that introverts were people that preferred their internal world of thoughts, feelings, fantasies and dreams. He thought that extroverts preferred the external world of things and people and activities. Since his definitions, the words have become skewed and people associate introversion with shyness and less sociability and extroverts with loudness and sociability. However, Jung had intended his definitions to refer to your ‘ego’. He believed that introverts where somewhat more mature than extroverts.

Functions: Whether we are introverts or extroverts we need to find ways to face the world. Each of us has our own method for this. Jung suggested that there are four basic ways, or functions.

The first is sensing. Sensing is our way of getting information from the world through our senses. A sensing person is good at looking and listening and generally getting to know the world. Jung called this one of the irrational functions, meaning it involved perception rather than judgement on information.
The second is thinking. Thinking means evaluation of information or ideas rationally, logically. Jung called this a rational function, meaning it involved decision making rather than simply taking in information.
The third is intuiting. Intuiting is the kind of perception that works outside the usual conscious processes. It is irrational like sensing, however, it comes from the complex integration of large amounts of information. Jung said it was like seeing around corners.
The fourth is feeling. Feeling is an evaluation of information by weighing one’s overall emotional response. Jung calls it rational. We all have these functions. The four functions are however, in different amounts. Some a superior, others are secondary or even tertiary. Many of us will develop two of these functions but our goal according to Jung should be to develop all four. Once again Jung sees the transcendence of opposites as the ideal.