One morning a student asked Seung Sahn Soen Sa, "How can one control thinking while sitting Zen?''
Soen Sa replied, "If you are attached to thought, your practice and your thoughts are different. if you are not attached to thoughts, thinking is practicing, practicing is thinking. This is called only practicing.''
The student asked, "What is only practicing?"
"When you first start driving, you cannot give your attention to sights or sounds, or else you will crash. However, after much practice, you can talk, look at things, and listen to the radio without any problem. Talking and sightseeing have become only driving. Your seeing, hearing, and speaking are non-attachment. It is the same with Zen. 'Only Zen' contains walking, eating, sleeping, talking, and watching television. All of these have become unattached thinking. This is only practicing."
"What is attachment thinking?''
"While driving, if you are attached to your thoughts, you will go through a stop sign and get a ticket; you will cross the center line and have a crash; you will, thinking that you are going to New York, instead head for Boston. In this way, attachment to thinking leads to suffering."
The student said, "Thank you very much. I understand well.''
"Since you understand, I will now ask you, are thinking and not thinking different? Are they the same?"
"When I am thirsty, I drink.''
"Very good. Go drink tea."