Is medicine a science?

Here’s something I read recently in a blog post (The Limits of (Neuro)science at Neuroskeptic) that started me thinking: “Will science ever understand the brain? … The notion that humans are complex and hard, while nature is easy, is an illusion created (ironically) by the successes of reductionist science. Some of the biggest questions facing mankind for eons have [been] answered so well, that we don’t even see them as questions. Why do people get sick? Bacteria and viruses. Why does the sun shine? Nuclear fusion. Easy.”

I started to write a simple reply, but it grew into the following.

Medicine is an applied science, not a pure science

It may be true that understanding the human brain is only an order of magnitude more difficult than understanding any other aspect of human biology. I’m uneasy, however, about putting ‘why people get sick’ in the same category as ‘nuclear fusion.’ Particle physics is a science. Questions can be asked and (usually) answered under the controlled conditions required by the objectivity that characterizes science.

Medicine is the application of certain sciences (molecular biology, biochemistry, medical physics, histology, cytology, genetics, pharmacology, neuroscience) to – ultimately — individuals. Each individual is the product of a unique, lifelong sequence of social, cultural, economic, and psychological (as well as physical, chemical, biological, and genetic) influences. To this day, we don’t really know why some people get sick and others do not. To my mind, that makes medicine an application of science – like engineering – not a science in itself.

Take bacteria and viruses. It’s true that pathogenic bacteria can make people sick, but what’s interesting is that they don’t always. Inspired by the germ theory of disease, medicine in the late 19th century held that a specific disease must have a single cause. The cause of tuberculosis was the tubercle bacillus: if you had the ‘germ’ you must have the disease. By the 1930s, medicine began to acknowledge that diseases could have multiple causes. And by the mid-20th century, medical textbooks explained that the presence of the tubercle bacillus did not always lead to TB. The bacillus was a necessary ‘seed,’ but the patient was the ‘soil’ in which the seed might or might not grow.

Does the scientific nature of medicine limit its potential?

I admit there may be large, indefensible holes in the assertion that medicine is not a science. How different is it from geophysics, which studies the earth and its environment (including the earth’s climate)? Isn’t that a science? Yes, because it adheres to the scientific process of measuring observable data, publishing the results for peers to review, and not giving credence to mere opinion. Surely the same could be said of medicine.

My real objection to medicine as a science is that by focusing on what can readily be quantified, it ignores what cannot, such as the social determinants of health and disease. Medicine’s historical desire for the respectability that comes with being a science gets in the way of discovering what could actually make us healthier.

Health care does not create health

Although we don’t know why some people get sick and others do not, we have some ideas. It could be what we eat, the quality of the air we breathe, our occupation, how much we earn, whether we feel our situation in life is fair, how we were treated as a child, numerous sources of stress in our lives.

Science prefers to isolate and understand one thing at a time, but the ideas I just mentioned are difficult to separate from their social context and cannot readily be studied in a controlled environment. The topics for medical research that seek and receive funding are those that investigate ‘reductionist’ theories of disease: things that fit neatly into categories sanctioned by the medical establishment and that can be readily measured, compared, and replicated. The cause and effect relationship between stressful living conditions and the health of individuals does not fit neatly into any simple mechanical model with the potential to make successful predictions.

For political reasons, it’s safer for medical research to stick to the limited agenda of what’s easily measured. If researchers investigated the social determinants of health, the answers could prove disruptive or inconvenient for prevailing economic (and thus political) interests. I’m thinking here of things like reducing air and water pollution, keeping carcinogens out of the food supply, and making sure drugs are safe before they’re prescribed for a large segment of the population. (The negative externalities of corporate culture, in other words.) It’s quite likely that social determinants of disease are extremely important for health. We don’t know for sure, not only because they’re hard to measure reliably, but because pursuing them tends to be politically unpopular.

Health care systems, informed by the scientific categories of medicine, are not designed to deal with things that cannot be easily quantified. Health care policy is set by politicians whose financial interests have been known to trump the common good. What preventive health care is good at these days (as opposed to the days when there was time for the doctor-patient relationship to offer comfort and relief) is creating guidelines for unacceptable levels of blood pressure, cholesterol, or blood sugar and prescribing drugs when tests indicate a patient has crossed an arbitrary but measurable threshold. That, and shift the blame for poor health onto the lifestyles of individuals, and be very expensive.

This is short-sighted.

A society that spends so much on health care that it cannot or will not spend adequately on other health-enhancing activities may actually be reducing the health of its population.

We need to figure out a way to liberate health from the financial interests that drive health care. Until then we’re stuck with a system that cares more about profiting from the narrow agenda of scientific medicine than it cares about improving health.

Jan Henderson is a historian of medicine who blogs at The Health Culture.

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  • buzzkillersmith

    Yup, an inexact applied science.  Next case. 

  • Bruce Ramshaw

    I believe what needs to be done first is to evolve our thinking beyond simple reductionist science to an understanding of complex systems.   Systems biology is a growing field and helps to understand and apply better thinking to the increasing complexity in our biologic world (made up of complex adaptive systems).  The solution begins with a change in our thinking, then a transformation of how we deliver care- measuring and improving complex and dynamic care processes.  The emergent system that comes from this will allow for a system driven by value of care rather than revenue growth.  I don’t think we get this from laws, mandates or financial incentives.  I think we just have to do it for its intrinsic value for our world.  The financial benefit would be great and financial reward would only occur for any organization, person, treatment or test that adds value.  We can’t measure value in our current system structure, so changing the structure of our delivery system is an essential step before we can measure and improve care processes defined in terms of value (quality, safety, satisfaction and financial combined).

    • Jan Henderson

      Thanks for your comment. Systems biology, yes. Holism, not reductionism. Its scientific success and deliverables will determine its future.

      It’s refreshing to hear your desire to change the structure of the current system so fundamentally. I wish someone would make a strong, scientific, and economically sound case for the idea that ultimately it is more profitable (not to mention humane) to address the causes of disease, thereby creating a healthy population, than it is to patch people up after they get sick. Even with that, however, the difficult part is going to be the transition. It’s a big job. Thanks for being visionary.

  • Surviving ADs

    We need much more attention to outcomes. “Scientific” research is fine, but no matter how good the studies look, if the applied research does not improve health, that line of treatment should be canned.

    Case in point: Psychiatry. Although thoroughly discredited, the “chemical imbalance” theory and a reliance on equally questionable medications still drives much psychiatric practice. Outcomes research indicates such practice is no better in improving health than placebo, while it generates much cost in side effects.

    Yet psychiatry persists in its delusions that because there is a mountain of research (highly compromised by commercial interests) about psychiatric medications, treatment with them still has validity. Surely an example of magical thinking in a pseudo-science!

    How many decades will it take before real-world results get back to the clinician and cause a change in practice????

    • Jan Henderson

      Thanks for your comment. I hear you. Medicine is big business and, especially when it comes to pharma, profits are the driving force not only for patient care but for the science itself. A great article on this is “Corporate Science and the Husbandry of Scientific and Medical Knowledge by the Pharmaceutical Industry,” written by an insider. When medical-scientific knowledge is driven by commercial interests, its truthfulness becomes problematic and vulnerable.

  • Christopher Johnson

    After doing medicine for 35 years I think it’s equal parts science, intuition, and blind luck.

    • Jan Henderson

      Yes, luck. Like when the uniquely individual patient happens to be an ideal fit for evidence intended for the ‘typical’ patient.

  • Margalit Gur-Arie

    “Why does the sun shine? Nuclear fusion. Easy.”
    Is it really easy? Nuclear fusion is the answer to How does the sun shine, not Why. I am not aware of a deterministic answer to the Why question.

    We understand enough of “nature” to explain and predict simple things. Perhaps we understand less about medicine, or biology, than other sciences, but I don’t see a sharp division in the essence of natural sciences. Whatever we manage to figure out is codified in “laws”, until they change, and the remainder is expressed in statistical terms.
    The only true science is mathematics, because we made it all up ourselves, independent of nature.

  • drjohnlufkin

    Putting it all together.  Science is the objective study of the world and universe so mankind can understand it.  Medicine is the application of this to the ill human.  Religion is the praise of the being who created this amazing world in the first place.  Medical studies are generally statistical analyses of observations by physicians / investors to apply to patient care for the patient benefit.  More and more these studies are being influenced by financial interests than objectivity of the studier thus leading to doubt about the results of the study.  This is leading to Catch 222 trillion as the medical profession has sold itself to big money.  We are no longer professionals, but employees of corporations whose only true objective is profit.

    • Jan Henderson

      I agree wholeheartedly with your conclusion. I often wonder how widespread this understanding is among doctors. It’s never stated that baldly in medical journals (who of course have advertisers to worry about). Could doctors and patients who realize this truth somehow get together and Occupy Medicine?

  • dsblanchard

    I think of neurologist, Oliver Sacks, (of Awakenings fame) here in his famous statement from his book “An Anthropologist on Mars” where he states, “Ask not what disease the person has, but rather what person the disease has.” Nicely written article, Jan!

    • Jan Henderson

      Ah, yes, Oliver Sacks. Along with that father of modern medicine, William Osler. Thank you.

  • Jan Henderson

    Ah, yes, Oliver Sacks. Along with that father of modern medicine, William Osler. Thank you.

  • DrJoe Kosterich

    The practice of medicine remains an art loosely based on some science. What we call health care is in reality disease care and is unsustainable. Collectively and individually we need to focus on helping people be healthy

    • Jan Henderson

      Very well said. Thanks for your comment

  • carolynthomas

    Brilliant observations here, Jan.  I too have been ruminating on this topic (as merely a dull-witted heart attack survivor, NOT a scientist, although I did spend 20 years of my life living with one – does that count at all?!)

    Medicine does in fact largely ignore important factors like social determinants of health and disease, mostly because, as you say: “…it’s safer for medical research to stick to the limited agenda of what’s easily measured…” 

    Yet even in research, we are ultimately reminded that “correlation does not equal causation” – despite how a study’s funders may prefer results to turn out through selective outcome reporting or data fishing or other ways that keep sites like Retraction Watch busy reporting journals that have (oooops!) been forced to retract published, peer-reviewed “scientific papers”.

    Love your ‘Occupy Medicine’ comment . . . .

    • Jan Henderson

      Thanks for your comment, Carolyn. What follows is not a direct response, but some thoughts that were stimulated.

      It would be nice if medicine could be perfect, since our lives depend on it, but of course that’s not possible in the complex and messy real world. As I look back at 19th century medicine as a historian, it seems it must have been easier to be a doctor then because patients did not expect as much, but also extremely frustrating because there was so little that could be done. 

      The practice of medicine is very conservative, as of course it should be when lives are at stake. The science of medicine – the published studies that are subject to retraction — may suggest changes in medical practice, but doctors know better than to chase the latest new thing. It’s called “clinical inertia.” Unfortunately, the advisability of changing a long-established medical practice only becomes certain in hindsight.

      An example of interest to you, as a heart attack survivor, is the use of epinephrine to treat cardiac arrest before a patient reaches a hospital. A new study published in JAMA ( suggests that while epinephrine increases blood flow to the heart (and thus produces a stronger pulse), it decreases oxygen supply to the brain and the rest of the body, resulting in a lower survival rate and poor neurological outcomes.

      As an accompanying editorial points out (, epinephrine for cardiac arrest has been a staple of medical practice since the 1960s. Now we have a huge (417,000 patients) observational study that raises questions about its use. Since it’s observational, it doesn’t establish cause and effect. It does provide evidence to justify ethically an RCT in which controls would not receive epinephrine. Until then, doctors are advised to “consider carefully whether continued use of epinephrine is justified.” I don’t envy doctors that decision.

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