‘In our everyday life, when we want to talk about something, we freely talk about it. When we want to go somewhere, before long, we are on our way. No sooner do we intend to possess something than we find ourselves grabbing for it. Our hands, feet, and tongue work so freely that we have no doubt that our thoughts are the sole master of our body, and that these thoughts are the “I” itself. But, when we try to measure and manage everything through thought alone, we find that things do not work out so well and we suffer in the end. For example: I can enjoy a delicious feast placed in front of me as much as I like, but if I want to digest it quickly and smoothly, my stomach might not be able to…
When we consider these facts carefully, we come to understand that our thoughts are neither the masters of our bodies nor the “I” itself. It would be better to think of thoughts as secretions produced by our brains, just as salivary glands secrete saliva and the stomach secretes gastric juice. In any case, the sense of “I” which is produced by the thought is not the master of the individual.
If you realize that your activities are not based on though alone, you let go of thought. Strangely enough, whether you think about it or not, the heavy meal in your stomach gets digested completely. When sleeping, we continue breathing the necessary number of breaths per minute and the “I” continues to live. What on earth is this “I”? I can’t help but feel that this “I” is the self that is connected with the universe. In the spring, shoots come out of the ground. In the fall, leaves turn colors and drop from the trees. All these things are an expression of the life force of the true self.’ (The Zen Teaching of Homeless Kodo)
I have used Uchiyama Roshi’s observation of thoughts being merely the secretions of the mind on many occasions while teaching. I have found it a wonderfully concrete way to remind ourselves that we spend way too much energy and attention on them, and that there are other things we can listen to, in the body, through zazen especially.