Scientology Basics - Knowledge, Control and Responsibility
When you were first learning to drive how was your control of the car? How willing were you to be the one in charge of the car? Your Control and Responsibility were low because you didn't know much about the car - your Knowledge was low. But as your knowledge increased you became more able to control the car and more willing to be responsible for it.
These three factors operate in a similar way to Affinity, Reality and Communication. Raise one and the other two will increase, decrease one and the other two will decrease. For example, let's say you are a very good driver, but you break your arm. While your arm is out of commission you are probably not going to be willing to drive your family around - you are not willing to take the responsibility, because your control is way down.
The principle is often referred to as the KRC Triangle and is covered in the book Scientology 0-8, the Book of Basics.
Scientology 0-8: The Book of Basics in 9 languages.