From the book Dianetics 55! The Complete Manual of Human Communication by L. Ron Hubbard
The Components Of Understanding
In Scientology, we have a great deal to do with this subject called understanding. Understanding contains very specific parts. These parts are: AFFINITY, REALITY and COMMUNICATION.
Each of the three parts of understanding—affinity, reality and communication—are very closely connected to one another. If there is a change in one of these, the other two also change. Because each is so dependent on the other, you can think of them as a triangle: You raise or lower one corner of this triangle (decrease or increase the affinity or reality or communication) and the other two corners also raise or lower. This is called, therefore, in Scientology, the A-R-C Triangle.
Affinity
The word affinity is used here to mean love, liking or any other emotional attitude. Under “affinity” we have whether or not we like people, whether or not we can live near people, whether or not we feel emotional toward people. The different emotions such as apathy, anger, boredom, enthusiasm each show different levels of affinity.
Reality
By reality we mean “the solid objects, the real things of life.” Reality is what is perceived (seen, felt, heard, etc.). Reality is agreement of what is or what exists. Something that is real is something that we agree exists and can perceive. The reverse would be disagreement, whereby two or more persons do not agree on what is true or what is real.
That which is real is real simply because it is agreed-upon and for no other reason.
Communication
Communication is the most important of the three parts in bringing about understanding.
A communication is a message or a particle, going through distance in a certain direction between two exact points.
A very simple way of saying what communication means is the shift (or movement) of a particle from one part of space to another part of space. A particle is the thing being communicated. It can be an object, a written message, a spoken word or an idea.
How To Use The ARC Triangle
The ARC Triangle can help you to answer these questions: How should I talk to people? How can I sell people things? How can I give new ideas to people? How can I find what people are thinking about? How can I handle my work better?
Based on how the ARC Triangle works, the way you would be able to talk to any person is by finding something to like about him and discussing something with which he can agree.
If you have problems getting a new idea accepted or understood by another person it is because you did not first talk about things that the other person does know something about. You must first establish reality by finding something with which you both agree. Then you would try to maintain as high an affinity level as possible by knowing there is something you can like about him. And you are then really able to talk with him. If you have not first established something you like about him and find something you both can agree on, it will not be easy to talk to him.
Excerpted from The Scientology Handbook booklet: The Components of Understanding by L. Ron Hubbard