Or is that inaction?
Wu Wei can be a complicated principle in Taoist philosophy, because it can be translated in different ways, presenting various meanings to English speakers.
Wu Wei can be translated as “non-action.”
Or as “actionless action.”
Or as “not doing.”
The overall sense is that something is not being done, even when something is being done. That's close to the truth, for Wu Wei signifies the opposite of how many Westerners attempt to accomplish their goals...we tend to grit our teeth and roll up our sleeves and grunt our way through an activity, attempting to physically force our way through mental activities, and to mentally force our way through physical ones.
The logic behind Wu Wei is very simple: Life is natural, and what arises from the universe arises naturally. Insofar as everything is natural, there is little reason to rely on much force (except when that force is also natural) to push things, or to make events happen in unnatural ways. If something is meant to be, it will occur on its own.
The human body is the best example of this, for the lungs act as a bellows and without our effort they provide the body's cells with oxygen and remove impurities from the blood. The brain operates without our forcing it to, and in fact works best when relaxed—as if it was a muscle—and exerting too much force in thought is often counterproductive to thinking. The muscles, and bones, and ligaments, too, operate efficiently and do what they evolved to do without our forcing them to do anything. Simply letting the body work in its own way is usually the best way for it to work.
If we let go of controlling our bodies and let them react to the world around us, we will find that our bodies are better prepared for survival and growth than “we” are—the we that is poorly designed for survival and growth is the Ego that insists only It can do things right, and that it needs to be there pushing everything else to do better.
This is likely what the ancient Chinese observed: that stopping the Ego did not stop the body, or even the mind, but that both mind and body operated more efficiently without the Ego barking orders at it.
On another level:
On another level Wu Wei is a trust in the process of the Universe. It is trusting that through practice, mastery will naturally be achieved, and once mastery is achieved, there is no need to do anything else, anything outside of the task at hand.
If one has mastered something, it's not the conscious mind that has mastered it, but the subconscious. That knowledge is not necessarily visible to us, but comes to the conscious as an intuition to rely on when needed. We can react in the best way in every situation, so long as we let intuition guide us and not second-guess the process.
Wu Wei is trusting that everything will work out if left alone, that the grass will grow, that the sun will shine, that society will function, that children will grow up.
If I study, I will learn. I do not have to over-think my actions, but simply read and learn.
If I am human, I will have relationships. There's nothing special that I need to do, no special effort I must put forward to attract people to me, or to keep them by my side, other than being myself. I don't have to “put on airs” to impress anyone.
Not only is Wu Wei about trusting that the world will work itself out, it's also about finding the most efficient course of action. Wu Wei is sort of a law of conservation. Like water seeks the lowest place, flowing with gravity, but never fighting itself or attempting to go over (or through) mountains it can go around, human beings can also find the easiest route through a task.
If I wash the dishes, they will become clean. There's no trick or special effort that I must put into washing them. Gentle, consistent strokes with a rag will clean dishes better than intense effort, pressing the rag as hard as I can against the glass. The difference is in the energy I've saved.
This is true of much of what we try to do in life. There's an efficient way to do anything and everything, and this is “not doing.” It's simplicity in action. It is practical.
When we run, it's best to move as little as possible (a simple motion instead of flailing) and in a straight line. It's best to relax the body so that it flows fluidly, to smile instead of frown in intense effort.
This benefits us by giving us more energy to sustain activities for longer periods of time. In athletics, in intellectual pursuits, in the daily grind of work, in relationships, in parenting, in politics, and in every other aspect of life we devote ourselves to. Finding the path of least resistance to a goal—not the path of least resistance away from adversity—is what Wu Wei is. This is embodied by the story of the butcher who never sharpened his blade because he always cut between the spaces where the meat connected to the bone.
The Universe goes its own way, and Wu Wei suggests going with it instead of trying to carve our own canyon out of it. Wu Wei is about accepting what exists before us now and working with what the Universe has given us, rather than to try to take what isn't there, or to manipulate reality into something unnatural—something that will not last despite our efforts.
Wu Wei goes hand in hand with our knowledge; not our conscious knowledge of facts and figures, but the unconscious knowledge of ways, of roads, of Tao.