Thoughts & Reflections |

Tetsunori Koizumi, Director

What does the immune system mean from the perspective of Buddhist thought? To pose this question, in a way, is meaningless as there is no explicit discussion of the immune system in the Buddhist suttas. However, it is possible to talk about what the immune system means in the context of the Buddhist view of the world as expounded in the suttas and commentaries.

The idea that the immune system is a defense system we humans possess and develop against invading pathogens must be said to be a foreign idea in the Buddhist conception of life and matter in the universe. However, as a system that is formed in and around us, there is certainly a place for the immune system in the interconnected and interdependent web of causes and conditions called paticca-samuppada, usually translated as “dependent origination”. As a system that is formed in and around us, there is certainly a place for the immune system in that interconnected and interdependent web of causes and conditions among all living and non-living systems.

The term that corresponds to a “system” in Buddhism would be sankhara, which is a Buddhist term that refers to “an entity that is constructed or put together” as it combines two words: san (together) and karoti (to make). A sankhara is usually translated as a “compound entity”, a “conditioned phenomenon”, or simply a “formation”. Another Buddhist term that corresponds to a “system” would be dhamma, written with the lower-case “d” to distinguish it from Dhamma, which refers to the Buddha’s teachings. A dhamma is usually translated as a “phenomenon”. As a sankhara, or a dhamma, the immune system is intimately tied up with all the other sankharas and dhammas that come and go in the interconnected and interdependent web of causes and conditions among all living and non-living systems.

As a sankhara, or a dhamma, the immune system is subject to tilakkhana, or the “three characteristics of existence”: anicca (impermanence), dukkha (suffering), and anatta (no-self). As the Buddha states in Anguttara Nikaya, for example, “Bhikkus, whether Tathagatas arise or not, there persists that law, that stableness of the Dhamma, that fixed course of the Dhamma. (1) Sabbe sankhara anicca (All conditioned phenomena are impermanent), (2) Sabbe sankhara dukkha (All conditioned phenomena are unsatisfactory), and (3) Sabbe dhamma anatta (All phenomena are without self).” (Anguttara Nikaya, III. 136)

The first characteristic of existence when applied to the immune system implies that it, as a sankhara, is subject to the law of anicca, or “impermanence”. To be more specific, the immune system is an evolutionary system that undergoes change and transformation along with all the other systems in the universe. The second characteristic of existence implies that, while it does perform a useful function of protecting us from external substances that threaten our health, the immune system is to be treated as a source of dukkha, or “suffering”, not as an object of attachment. Lastly, the third characteristic of existence implies that the true nature of the immune system, like any system in the world around us, is of the nature of anatta, or “no self”. Given that we humans are of the nature of anatta as implied by panca khandha, or the “Five Aggregates”, the immune system as a system formed in and around us is also of the nature of anatta.

If the immune system is, as a sankhara, or a dhamma, subject to the three characteristics of existence, what should we make of the role it plays for us from the Buddhist perspective? To be sure, we humans are endowed with the innate, as well as the acquired, immune system. But is there more to the immune system than the mere designation scientists employ to highlight the role it plays in protecting us from external substances such as bacteria, fungi, and viruses that threaten our health?

The reason we possess the immune system is because we humans have co-evolved with all the other living and non-living systems in the universe. From the Buddhist perspective, the immune system is not therefore a defense system that shields us from invading pathogens. Rather, it is an adaptive system that allows us to co-evolve with pathogens, serving as an interface between the individual human being and all the other systems in the universe. For Buddhist practitioners, what this means is that we need to develop panna, or “wisdom”, to see things as they really are. Here again, the Buddha reminds us of the need to develop wisdom through constant practice: “When through wisdom one perceives, ‘all sankharas are transient,’ then one is detached as to misery. This is the path of purity. When through wisdom one perceives, ‘all sankharas are suffering,’ then one is detached as to misery. This is the path of purity. When through wisdom one perceives, ‘all dhammas are without self,’ then one is detached as to misery. This is the path of purity.” (Dhammapada, 277, 278, 279)

Tetsunori Koizumi, Director

The idea that we humans are endowed with immune systems that protect us from external substances that threaten our health goes as far back as Huangdi, the legendary Yellow Emperor. Huangdi Neijing (The Inner Canon of the Yellow Emperor), which has been the canon for over 2,000 years for practitioners of Eastern medicine, explains how immunity works in terms of two types of qi-energy: wei qi (protective qi-energy) and ying qi (nutritional qi-energy).

The “protective qi-energy” and the “nutritional qi-energy” together protect us from the “evil qi-energy”, which refers to external substances in the environment that invade our body and cause illness. The “protective qi-energy” protects us from the “evil qi-energy” by establishing barriers on the skin surface by controlling perspiration and the body temperature. The “nutritional qi-energy”, on the other hand, protects us from external substances that have managed to enter the body through breathing, eating, and drinking by producing pure nutrients from the food and drink we consume. Transformed into blood, the pure nutrients are carried into various parts of the body. In contrast to the “protective qi-energy” that works on the skin surface, the “nutritional qi-energy” works within the body as the energy in the form of pure nutrients.

Modern Western medicine also explains how immunity works for us in terms of two types of the immune system, called the “innate immune system” and the “acquired immune system”. The “innate immune system” is the one that we have inherited from our parents, and is active from the moment we are born. The “innate immune system” goes into action immediately when it recognizes an invader. The invader is surrounded by the immune system cells, called phagocytes, and is killed inside these immune system cells.

The “acquired immune system”, on the other hand, produces cells called antibodies to protect us from an invader. Unlike the “innate immune system”, the “acquired immune system” does not go into action immediately because it needs to develop antibodies such as B-lymphocytes after the body has been exposed to the invader. Once these antibodies are developed, the immune system will protect us from the invader by recognizing and responding to it. Another important difference between these two immune systems is that, while immunity protection provided by the “innate immune system” is non-specific in that it works for all invading pathogens equally, immunity protection provided by the “acquired immune system” is specific in that it works only for specific types of invaders.

From the above descriptions of the “innate immune system” and the “acquired immune system” in modern Western medicine, it appears that the former corresponds to the “defensive qi-energy”, and the latter to the “nutritional qi-energy”, in traditional Eastern medicine. Huangdi Neijing (The Inner Canon of the Yellow Emperor) describes how the “defensive qi-energy” goes into action when the “evil qi-energy” from outside causes the blockage of qi-circulation in and around the body. The “defensive qi-energy” goes into action through changes in perspiration and the body temperature. Thus, the “defensive qi-energy” can be seen as playing the role of the first line of defense against disease-causing external substances, just as the “innate immune system” does.

The “nutritional qi-energy”, on the other hand, responds to the “evil qi-energy” from outside by transforming the nutrients from food and drink into blood, and thus circulates throughout the body, including the internal organs. It is not clear whether the “nutritional qi-energy” acquires a memory of the invader like the “acquired immune system” in Western medicine, but it provides us the internal protective power that we acquire in the form of nutrients circulating within the body.

While there are certain degrees of correspondence between the conception of the immune system in traditional Eastern medicine and that of the immune system in modern Western medicine, there is one important difference between the two, and that has to do with the ubiquitous nature of qi-energy. As the energy that pervades everything in the universe, qi-energy provides a vital link between the individual human being and the universe. In other words, the immune system serves as an interface, or a link, that connects us to all the living and non-living systems in the universe. This is indeed the reason why the question of health is not just a matter of how well our individual body is functioning, but is intimately tied up with the overall condition of the universe that provides us the air we breathe, the food we eat, and the climate for our living.

Immunology in Western medicine has undergone some important changes in recent decades to incorporate such a cosmic perspective as seen in traditional Eastern medicine. While classical immunology used to see the immune system as the body’s defense system, protecting us from external factors, new immunology sees it as an adaptive system that relates itself to these external factors and undergoes a process similar to biological evolution itself. To put it succinctly, the immune system is an adaptive system in the worldwide web of life and matter and keeps evolving along with all the other systems in the universe.

*An abridged version of the paper presented at the Science of Life Conference, May 8, 2021.

What Does the Immune System Mean from the Perspective of Buddhist thought?

The Immune System as an Adaptive System in the Worldwide Web of Life and Matter*