A Scientific Theory of Illness and Disease

If a super-intelligent alien was to visit our planet and search for a scientific theory of illness, she might conclude the our prevailing theory consists of “sell the drugs” and “damn the consequences”. She might also know that the scientific theory of illness consists of:

Illness Theory #1: Every illness has a cause. 

ELEMENTARY ILLNESS is an illness with a single cause and its negative consequences. 

There are three basic types of illness elements: illness, injury, and blockage. An causal illness consists of the signs and symptoms resulting from a cause. An injury illness consists of the injuries resulting from a cause, often in the past. A blockage illness consists of a blockage to healthy flows of life, stemming from a cause – usually in the past.

COMPLEX ILLNESS is an illness with more than one element arising from a single cause or causal chain.  For example one cause might result in signs and symptoms and also an injury. There are four different types of complex illness possible, based on three types of elementary illnesses.

COMPOUND ILLNESS is an illness consisting of two or more elementary illnesses.

Does our medical system have a theory of illness?  You might be surprised to learn that there is no prevailing scientific theory of illness. There are many so-called theories of illness, but none that achieve the simplicity of a scientific theory.  Illness seems to be everywhere in practice, but nowhere in theory.

Why is there no scientific theory of illness? 

eNotes says: “Anthropologists often divide theories of illness into two broad categories: personalistic and naturalistic.  In a personalistic system, illness is believed to be caused by the intervention of a sensate agent who may be a supernatural being (a deity or dead ancestor) or a human being with special powers (a witch or a sorcerer)… Naturalistic theories of disease causation tend to view health as a state of harmony between a human being and his or her environment; when this balance is upset, illness will result.

Neither of these classes of theories of illness contains the simplicity and clarity required for a useful scientific theory of illness.  And neither is recognized by the medical establishment as a clear, useful theory of illness.

“Personalistic” theories are basically superstitions that might be used to explain anything – but not in any scientific manner.

“Naturalistic” theories are closer to being useful, but as defined above are quite limited. They do not consider that illness can come from failure of internal harmonies, not just harmonies with externals. They also tend to measure illness as binary – either balance is maintained, or balance is upset.  But the balances of healthiness, and of illness, are much more complex.  Life, healthy life, uses balancing and unbalancing as a source of leverage and power.

The book: Theories of Illness: A World Survey, by George Peter Murdock, claims to be “An important contribution to medical anthropology, this work defines the principal causes if illness that are reported throughout the world, distinguishing those involving natural causation from the more widely prevalent hypotheses advancing supernatural explanations“.

But this book is not about illness.  It not a scientific exploration of ‘theories of illness’, it is, instead a ‘history (anthropology) of the many theories of illness throughout different societies throughout history’. We can quickly see from a scan of the chapter titles that this book does not aim to represent any single theory of illness, rather it presents as many as the authors can find. It is, as stated in the forward: “a landmark of comparative studies”. But there is no attempt at scientific analysis.

If we are to have a scientific theory of illness, we need a theory that is independent of the opinions of specific patients, with specific illnesses, and independent of specific doctors with specific cures.  The theory of illness also needs to be independent of any theories of treatments.

Who decides if you have an illness?  Can you decide?  Can your spouse, your friends, or your priest decide? Or does it require a doctor to identify the illness before it exists as an illness? Legally, only a doctor can diagnose a disease – but an illness must be present before a disease can be diagnosed. What if two doctors, or more, happen to disagree?  Is there a court that decides if you have an illness or not?  Clearly, deciding who has an illness is not a trivial question.

In this discussion of illness and the theory of illness and disease, I will use the assumption that you have a disease when a doctor issues a diagnosis of a medical condition. That is the definition that is in primary use in today’s medical system. It is clear that an illness must be present before a disease can be diagnosed.

If you have an illness, the first questions you might consider are: “am I going to live” followed by “how bad is it?”  Neither of these questions speak to a general theory of illness – both are personal and answers are different for every individual illness.

The next question should be “what is the best cure for this illness?” This question, is a total mystery for most illnesses today, because of the weakness of our current theory of illness. Cure is simply not defined for most illnesses today. Many current medical dictionaries and references make no attempt to defined cure, cures, cured, or even incurable. “Best cure” almost seems like a silly question.  It is not.

Finally, you might ask “what caused this illness?”  So that you, and your family and your communities, might avoid this illness in the future.

We can find the beginnings of a theory of illness in the last question.

what caused this illness” – implies an underlying awareness that illness has a cause. This gives us the first theory of illness.

Illness Theory #1: Every illness has a cause. 

This simple theory encompasses virtually all of current theories of illness, from the ‘germ theory’, to all of the ‘personalistic’ and ‘naturalistic’ theories. It might be argued that this theory is too simplistic. However, this argument quickly becomes moot when we use this fundamental statement to move forward our understanding of illness. “Every illness has a cause” is the foundation of any theory of illness. The theory is simple because we need a simple, solid foundation to build upon.

Note: An elementary illness, or an illness element has a single cause.  However, be aware that whenever we find a ’cause’ of an illness we can find a chain of causes by asking “what is the cause of this cause?” and “what are the immediate consequences of this cause?” An illness element has a single chain of causes. No ‘things’ cause illness. Every cause is an action, or a process, not a ‘thing’.

When we look at causes of illness – in general as opposed to specific illnesses, one thing quickly becomes clear, and has been stated by many people studying illness. Illness can be caused by deficiencies.  Illness can also be caused by excesses. Many theories of illness and of healthiness strive to maintain ‘balance’.  Balance lies between deficiency and excess. There might be deficiencies or excesses of nutrients, of exercise, of sensations, of many many factors.  They might be, if you believe in personalistic theories, caused by an excess of bad wishes from someone who wants you to be sick.

This scale shows that healthiness exists in balance – illness emerges from deficiencies or excesses in some attribute of healthiness. Simple illnesses have simple causes, complex illnesses have combined or complex causes. Actually, it’s a bit more complicated. All of the balances of health are active. We use balance, in many ways, to move forward in life. We walk by unbalancing and recovering.  We run by taking more risk. A balance that one person considers to be healthy might easily be judged as, or be an unhealthy balance for someone else.

An ELEMENTARY ILLNESS is an illness that has a single cause, a single imbalance or lack of ability to use balancing effectively.  

A COMPOUND ILLNESS is an illness with more than one cause. Every compound illness consists of two or more elementary illnesses. 


These are close to the Naturalistic theory of illness.  But it quickly becomes clear that we need to add a simple refinement.

Healthiness to Unhealthiness to Illness to Disease

Healthiness exists in balance, and when we are able to use balancing effectively.  As we lose balance, or lose ability to use balancing, we move towards unhealthiness.  As unhealthiness becomes more severe, we arrive at illness.  The boundaries between healthiness, unhealthiness and illness are fuzzy and flexible.

Disease, however, is more clearly defined. A disease is a classification system for illnesses.  A case of a disease is that which has been diagnosed. Disease only exists when it is diagnosed and only exits from the point of diagnosis. However, there is a technical problem as this image relates to cure.  There is no definition of cured, and once a disease is diagnosed, there is no technique to identify a cure.

Each possible cause of illness, each imbalance, has a threshold. Below the threshold, and you might have an illness, or not; above the threshold you might have a disease. 

Medical researchers work to define the line, to develop a series of diagnostic tests indicating that you ‘have a disease’, or not. However, in today’s medical practice, this line is often defined by signs and symptoms – without any respect for cause.

We need to measure both cause and consequences to determine if an illness exists. Every illness is an intersection of cause and consequences – it is possible to have either cause or consequences without the illness.  The illness only exists when they exist together, in a causal link.

What if you have an inability to balance that is not yet an illness and thus not yet a disease? At present, we have no name for this status, although it is, by definition, likely present more often than disease. We might call this ‘unhealthiness’. If it is serious enough to cause a problem for the patient (or the doctor) it can be called an illness, but it cannot be called a disease until has been diagnosed.  Of course a disease can be diagnosed retroactively.

UNHEALTHINESS is an imbalance (a deficiency or an excess) or inability to use healthy balancing effectively, that is not severe enough to be classified as an illness. Note: we often consider unhealthiness to be an unwillingness to use balance effectively, for example consuming too much alcohol, or smoking too many cigarettes, or not maintaining significant care about cleanliness. The line between ‘inability to do’ and ‘inability to choose’ is interesting.

Healthiness is the opposite of unhealthiness. When healthiness increases, unhealthiness decreases.  When unhealthiness increases, healthiness decreases.

Health improves when the balances improve.  When we are more able to use balancing and imbalances to move forward in life. When imbalances can be used effectively, we are healthier.

Because health is dependent on active balancing, perfectly optimized health is not possible.  Many of the balances of health are in constant flux due to life. Many of the balances that move us toward optimal health are in competition. We might wish for an athlete with optimal strength, optimal flexibility, optimal speed, optimal endurance – but we soon learn that optimal strength causes a decrease in flexibility, and acquiring optimal speed creates a deficiency in endurance. Perfectly optimal health would consist of optimizing many thousands of healthy balances – many of which are in competition.


As we develop a scientific theory of illness and disease, we can use it to develop a scientific theory of cure. 

The best health requires Personal Health Freedom to choose which balances are important to each self.  Everyone has a right to life, liberty, and the pursuit of healthiness.

As we work with this theory of illness, we will learn more effective techniques for the early detection, prevention, diagnosis, treatment of and recovery from illness.

amazonBookImgeHealthicine: The Arts and Sciences of Health and Healthiness is about the study of health.  Healthicine is a new field of study.  There are no experts – only those who might claim to be experts because of their successes in studying illness.

to your healthiness, tracy

This is an updated version of a post originally published in February 2013, updated in March 2017, further updated on April 21, 2017 – as I work on revisions to the initial concepts of healthicine.
Updated Oct. 20, 2017 to add the concept of a complex illness.


About Tracy Kolenchuk

Founder of Healthicine.org. Author of two books about healthicine; Healthicine: The Arts and Sciences of Health and Healthiness Healthicine: Introduction to Healthicine
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