Jan 19 2012
A recent article defending Traditional Chinese Medicine (TCM) provides, ironically, an excellent argument for the rejection of TCM as a valid form of medicine. The authors, Jingqing Hua and Baoyan Liub, engage in a number of logical fallacies that are worth exploring.
Their introduction sets the tone:
Traditional Chinese medicine (TCM) has a history of thousands of years. It is formed by summarizing the precious experience of understanding life, maintaining health, and fighting diseases accumulated in daily life, production and medical practice. It not only has systematic theories, but also has abundant preventative and therapeutic methods for disease.
It may be trivially true that TCM has a long history, but it is hard to ignore that the placement of this statement at the beginning of a scientific article implies an argument from antiquity – that TCM should be taken seriously because of this long history. I would argue that this is actually a reason to be suspicious of TCM, for it derives from a pre-scientific largely superstition-based culture, similar in this way to the pre-scientific Western culture that produced the humoral theory of biology.
The next line is an admission that TCM is largely based on anecdotal information, described as the “precious experience” of life. This is a point that is often overlooked or not understood by proponents but central to the scientific/skeptical position – what is the value and predictive power of “precious experience” in developing a system of medicine?
I maintain that there are many good reasons to conclude that any system which derives from everyday experience is likely to be seriously flawed and almost entirely cut off from reality. Obvious short term effects, the lowest hanging fruit of observation, are likely to be reliable. Uncontrolled observation is a reasonable way to discover which plants, for example, are deadly poisons. This is likely to produce some false positives but few false negatives, which is fine for survival.
Other obvious effects, like nausea, diarrhea, and psychedelic effects are also easy to discover. Similarly it was probably obvious that people need to eat, breathe, and drink in order to stay healthy and alive. But records of pre-scientific thinking about health and disease shows that little else was.
Pre-scientific doctors thought, for example, that pus was a good thing, a sign that a wound was healing. They also did not realize that removing blood from the body was harmful, because they did not understand the vital physiological effects of blood and had fanciful superstitious notions about its role in the body.
So there are severe practical limits to what uncontrolled life experiences could figure out about health and disease. Every culture figured out some basic things, like local plants that had some uses, how to treat some forms of trauma, and to midwife childbirth, but could not figure out the complexities of biology, physiology, anatomy, biochemistry, infection and disease pathophysiology.
Understanding health and disease took a more sophisticated method of observing nature – science.
How, then, could a pre-scientifc culture without any knowledge of modern biology and without the methods of science develop a valid and effective system of medicine? The answer is – they couldn’t. In addition, there is now a large body of psychological research showing the many ways in which people systematically deceive themselves when it comes to finding correlations and making assumptions about cause and effect.
There is nothing about the Chinese culture or the Chinese people that should make them exempt from these documented psychological effects, or that would make their culture unique among the world’s cultures in stumbling upon notions about health and illness that were actually correct. It is extreme cultural hubris to think otherwise.
As evidence for this, in my opinion, is the very description of TCM given by the authors. They give a description of TCM philosophy, breaking it down into three components. The first is yin-yang:
According to the theory of yin–yang, all opposite matters in the universe, which are interrelated with each other or two opposite aspects within one matter, can be defined as yin or yang.
This is a “push-pull” philosophy of health – but it is just that, a philosophy. Nothing has been discovered in physiology that correlates with yin-yang, that would lead to the prediction that a yin-yang systems exists, or supports the existence or effects of yin-yang. It is just a made-up notion without any basis in physical reality – just like the balancing of the four humors of Galenic medicine.
Next is the five phases:
The five phases theory defines the nature of matters based on the related characteristics of wood, fire, earth, metal, and water. The five phases maintain the generation and restriction relationship among them. TCM uses five phase theory to describe the relationship between five zang and their physiological function, five zang and structure and function of various parts of the human body, and also the correlation between each part of human body and nature and society.
Your liver, apparently, has the aspect of wood. This is an elaborate belief system, just like astrology, and has as much validity. It is rather poetic, also like astrology, and one can understand how a pre-scientific society would develop such ideas in order to attempt to understand something as complex and mysterious as the human body and illness.
There is no reason to presume, however, that such a description offers any insight into how the body functions or how to approach or treat any particular ailment. The authors give an example:
In the treatment of the syndrome of disharmony between the heart and kidney caused by deficiency of kidney-yin and hyperactivity of heart-fire, according to the law of ‘water restrains fire’, we can use the therapy of reducing fire and reinforcing water.
I would rather treat a problem with heart or kidney function based upon a good ‘ol reductionist view of heart and renal function, understanding the role of blood pressure, body fluids, kidney function and regulation, electrolytes, etc. The notion (“law”?) that water restrains fire does not seem to offer any insight into how to treat a pre-renal syndrome.
Finally there is the visceral and meridian theories, which constitute an alternate (meaning incorrect) way of understanding the organs of the body:
Also, combining visceral manifestation theory with yin–yang and five phase theory, TCM has formed its own understanding towards the law of physiological and pathological changes of the human body. For instance, the liver matches wood, and the spleen belongs to earth. The over-acting of wood will lead to over-restraining on earth. Thus, we can see patients with transverse invasion of the stagnated liver-qi attacking the spleen.
How exactly does stagnated liver-qi attck the spleen? How would this be diagnosed? What I am saying is – what is the reductionist understanding of these concepts? It is common for proponents of such alternate ways of knowing to denigrate reductionist science, but if a way of “understanding” how something works reflects reality, then it should make sense and hold up to the evidence all the way down.
“Reductionist” really just means deeper levels of understanding how the world works. It should not be confused with “hyperreductionism” which means ignoring or minimizing higher order levels of organization and function. You cannot, for example, understand how the body works just from biochemisty, or even from studying single cells. You have to understand how tissues, organs, and the whole body works together.
Science, actually, takes the most holistic view of health and disease, for it attempts to understand how the body works at every level of organization, and recognizes the folly of ignoring any level. You cannot ignore how the system works together, nor can you ignore how the individual parts work all the way down to their most basic components.
Ancient philosophies of medicine, however, either ignore the deeper levels of function, or make up fanciful underlying concepts, like wood and earth, that have nothing to do with reality.
Finally they describe the meridians:
The meridians transport qi and blood all over the body, link up the upper and the lower, the inside and the surface of the human body, response and conduct the information.
Except, there is no evidence that the meridians actually exist. At the risk of sounding redundant, they are as made up and fictional as the ether, flogistum, Bigfoot, and unicorns. The linking of qi and blood is reflective of the fact that the notion of qi is historically tied to blood, and techniques such as acupuncture and cupping were also closely related to bleeding techniques that we are more familiar with from Galenic medicine.
This leads to the next section on therapeutics in TCM. Of course they discuss acupuncture and also moxibustion and massage, but give very quick descriptions. They state multiple times that these techniques “treat disease” – which is an odd and extraordinary claim for several reasons. There is, of course, no evidence that acupuncture or moxibustion alters the course of any disease. You have to believe in the notions of qi etc. described above to believe that there is any plausibility to the use of acupuncture for disease. Even for symptomatic treatment (the bulk of scientific acupuncture studies) the evidence is weak to negative.
The authors also describe TCM herbalism, stating:
Currently, there are over 12,800 types of Chinese medicinals known by people, including over 11,000 medicinal plants, over 1500 medicinal animals, and over 80 medicinal minerals. Also, there are approximately 1 million TCM prescriptions found.
This relates to my main point above – how could practitioners have sorted out the risks, benefit, side effects, interactions, indications, pharmacodynamics, and pharmacokinetics of 1 million preparations without using any systematic scientific methods? This would be a challenge for a modern scientific institution, and would have been impossible for any pre-scientific society. One has to either ignore this issue, or assume preternatural abilities on the part of TCM practitioners, at the very least making them immune to all the mechanisms of deception and bias that seem to plague modern ordinary humans.
All of this background is just a long windup to what appears to be the main point of this article – the challenge of studying these therapies and idea with modern scientific methods. Those of use familiar with this line of reasoning can see the massive special pleading coming a mile away.
They outline five challenges to scientifically studying TCM – that TCM considers overall health (I guess rather than just one condition at a time), therapies require ongoing assessment and adjustment, multiple therapies are given simultaneously to work together, and there are multiple targets of therapy.
Let me turn this around a bit – assuming the premises of this reasoning are true (that TCM must include these higher levels of complexity) then it is true that TCM treatments would be difficult to study systematically. At the same time, however, they would make it very difficult (likely impossible) to derive any reliable conclusions about therapy from “precious experience”. I would argue that the same features that make TCM difficult to study in a controlled setting make it impossible to assess in an uncontrolled setting.
So how, then, can TCM practitioners have any practical knowledge about what therapies work and are appropriate in specific situations? Something akin to “magical intuition” is the only answer.
That point aside – it is difficult, but not impossible, to study such treatment. First, I disagree with the premise and believe it is just special pleading, an excuse for the lack of scientific evidence for TCM. In modern medicine we often use multiple treatments working together to address a complex syndrome. Each individual component, however, should contribute to the overall benefit, and should be able to demonstrate its contribution in controlled studies.
Any contribution too small to detect in clinical trials is probably too small to be of clinical significance. Also, even if we accept the premise that multiple treatments only work when given together, you can still study this in a controlled setting – by individualizes a holistic treatment plan and then giving it or a placebo substitute in a blinded fashion.
You may have noticed that I left off the fifth “challenge” to studying TCM (which is often used as an excuse for a lack of evidence). The authors write:
Finally, the cultural characteristic embodied in traditional Chinese medicine requires more consideration on ecological features of data in TCM when conducting statistical analysis.
I’m not sure what to make of that statement, and the authors give no further explanation. I would just point out that science – and reality – has no cultural characteristic. If something is true about the world, it is true no matter what culture you come from. The point of science is to be transparent and universal, so that anyone doing the same experiment, no matter what culture they come from, should have the same result.
TCM is a pre-scientific superstitious view of biology and illness, similar to the humoral theory of Galen, or the notions of any pre-scientific culture. It is strange and unscientific to treat TCM as anything else. Any individual diagnostic or treatment method within TCM should be evaluated according to standard principles of science and science-based medicine, and not given special treatment.
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