Causality in Chinese Medicine – The Issues of How and Why

The topic of causality is, in my opinion, the number one most important issue in medicine. People ask more questions about it, spend more time stuck on it, and know the least about it, than any other issue I can think of. There are three concepts that need to be discussed – causality, mechanism, and interpretation.


The first thing that needs to be said of causality is that causality is not linear in Chinese medicine.  A does not produce B, nor does A lead to B.  In Chinese medicine, we explain causality by saying that things which occur in relation to each other are causal to one another.  We may perceive the events unfolding in linear time, and assume that that which occurs first is the causal factor, but this is not true.  Fritjof Capra, in The Tao of Physics, describes the process of particle scattering.  He states that “The mathematical formalism of field theory suggests that these lines can be interpreted in two ways; either as positrons moving forward in time, or as electrons moving backward in time!  The interpretations are mathematically identical.”

As another example, the well known Zen teacher Taizan Maezumi Roshi explained that “Every action is complete in each moment as both cause and effect, for each action is both the cause of other things and the effect of other things… Firewood turns into ash, and does not turn into firewood again.  But do not suppose that the ash is after and the firewood is before.  We must realize that firewood is in the state of being firewood and has its before and after.  Yet having this before and after, it is independent of them.  Ash is in the state of being ash, and has its before and after.”  This is from his book Appreciate Your Life.

So we can understand the relational nature of events in Chinese medicine, and describe them in terms of causality using the concept of systematic correspondence.  That is, the underlying theory of Chinese medicine that all phenomena resonate at distinct frequencies and can be grouped accordingly.  The three categories of causation in Chinese medicine are:

  • Nei Yin – The internal causes of disease, or the emotions (sadness, joy, worry, pensiveness, anger, fear and shock)
  • Wei Yin – The external causes of disease, or the weather (the external pernicious influences of Wind, Cold, Dampness, Dryness, Fire, and Summer Heat)
  • Bu Nei Bu Wei Yin – The neither internal nor external causes of disease (includes diet, lifestyle, and trauma)

All of this occurs against the backdrop of constitution; but in the world, that is it for causality.  This means the following – sinuses are not a cause of disease, bacteria and viruses are not a cause of disease, herniated discs are not a cause of disease, etc.


Mechanism is the discussion of “how” in Chinese medicine. People generally want to know why they are sick, but a more fundamental issue is how they are sick. If a person has symptoms, regardless of the cause or anything else one may think about those symptoms, there has to be a mechanism whereby those symptoms are able to manifest. Mechanism is described in Chinese medicine under the heading of pattern discrimination. There are ten categories of pattern discrimination in Chinese medicine, stated here briefly. They are Eight Principles; Qi, Blood and Fluids; ZangFu (organs and bowels); Pathogenic Factors; Five Elements; Channels and Collaterals; Six Stages; Four Levels; Three Burners; Diseases. Almost all of western medicine is based on the Disease category. The other nine categories allow for differential diagnosis that describes disease mechanisms as they occur uniquely in each individual.


Although not formally a part of Chinese medicine, interpretation is the individual stories we create to make sense of causality and mechanism. The issue of “why” comes under this category. This topic raises an important issue. Why is always an existential issue, and is never answerable. We can never know objectively why we are sick. We can, however, use the concepts of causality and mechanism to help point us in the direction of a meaningful story as to what our illness means to us (see Disposition, also in this issue). When someone has back pain, and they go to the doctor, get an MRI, and find out they have a herniated disc, this does not explain why they are in pain. Nor does it explain the cause of the pain. Technically, it does not even explain the mechanism of pain. Rather, it explains a pathological finding that arises in relation to some pattern of disharmony. That is, the herniation is part of the picture, but it is neither the cause nor the mechanism, and does not explain why.

The following is an abbreviated but inclusive example of how this all comes together in Chinese medicine. A person complains of back pain. The first step in Chinese medicine is to categorize the disease. In western medicine this might be something like lumbar disc herniation, but in Chinese medicine the disease would be Yao Tong, or back pain. The next step is a discussion of causality. A textbook might list several of the causal factors, from among the three categories listed above, that commonly contribute to back pain. One might see brief paragraphs with titles such as “Fear Injures the Kidneys,” “Invasion of External Cold,” and “Excessive Physical Work,” covering respectively the categories of internal cause, external cause, and neither internal nor external cause. These need to be identified for the actual person, however, as there are many to choose from. The third step is to discuss mechanism. Patterns are chosen from among the ten categories described above, identified according to the person’s signs (through examination) and symptoms (what people complain of). We have now identified the disease, the cause, and the mechanism of action.

So this person may have back pain due to internal damage, such as Kidney Yang Vacuity. He or she displays many signs and symptoms of this pattern. It becomes apparent that this person greatly overworks and consumes large amounts of coffee, thus depleting their Kidneys. However, the person is only 30 years old. This pattern does not occur readily in a person that age, so it is likely that they were born with a constitutional Kidney deficiency. Fear is a deeply set issue in the person’s life, and it drives them to overwork and deplete their resources. Oh, and the person has a herniated disc.

This is a very simplistic yet accurate scenario. The person wants to know why they have pain, and determines it is the herniated disc. Yet from a Chinese medical model, the underlying constitution drives behaviors in the person’s life that eventually result in back pain. While causality and mechanism are non-negotiable, interpretation is fully negotiable. How this person chooses to integrate the information which points to the Kidneys, and thus to reactivity to fear, into a meaningful story, is up to them. In fact, they may dismiss the information completely and stick with the herniated disc story. The herniated disc is certainly real; it can just be placed in different contexts depending on one’s orientation.

Finally, clarity on the distinction between these three issues leads to more effective treatment. I routinely witness people endlessly pursuing the “cause” of their illness, in the attempt to understand “why” they are sick. Regardless of biomedical findings, this information is readily accessible through the diagnostic parameters of Chinese medicine. The information can allow each person to identify and focus on those factors which are making them better and those which are making them worse, and to put it all together into a useful story that allows for a deeper level of healing.