I see the term nondoing being used in different ways.
Personally, I prefer to not use the word since it can so easily be misunderstood and lead to unnecessary confusion.
But what does it really refer to? I don’t know enough about Taoist or Buddhist philosophy or practice to say for sure what is traditionally meant by the term, but I can say something about what comes up for me.
It can be quite simple. I can notice that what is happening, is already happening on its own. It lives its own life, on its own schedule.
Thoughts. Emotions. Sensations. Sounds. Taste. Smell. Choices. Action. A sense of doer or observer. They all happen on their own. They appear out of the blue. They live their own life.
There is already “nondoing” there since “I” am not doing any of those things. “I” am not doing anything that is happening, and really, this “I” is just an image of a doer or observer, and this image too is happening on its own.
So nondoing is just noticing this. It is simple, but not always so easy, especially at first or during daily life. But it is possible to get a taste of it when sitting down and, for instance, exploring what appears in the sense fields. It can even be quite clear. And with more familiarity with this terrain, it can be noticed in more and more situations throughout the day as well.
As always, “nondoing” can become a belief, whether obviously misunderstood (meaning not being active or engaged in daily life), or more “correctly” understood (noticing there is already nondoing in everything that is happening), and it can get quite weird. It can lead to a struggle within content of experience, an identification with one part of this content (doer or observer) imagining that it is trying to push away other parts of this content (choices, actions or the doer).
But it can also be a pointer, something to explore in immediacy, with curiosity and receptivity, and over and over again.
Trigger: The first few minutes of this talk by Jon Kabat-Zinn.