A Brief History of Evidence Based Medical Decision Making

To better know physical therapy's future it may be helpful to remember how we got here.

This history starts at the beginning:

Pre-history Primitive tribal societies/shamans

The earliest form of medical decision-making was usually vested in one 'holy' person.

Shamans held all medical knowledge and may have made decisions on various social, legal and religious issues as well. No rival source of scientific knowledge existed within the tribe that could challenge the shaman's decisions.

The shaman guarded the status quo and to question this person, who was often a powerful tribal elder or chief, usually meant exile or death.

469–399 BC Socrates (Athens, Greece)



Socrates of Ancient Greece began the tradition of questioning one's own beliefs to discover the nature and extent of ones' own knowledge.

The Socratic Method is the basis for the classic and the modern Scientific Method.

To Socrates, the greatest wisdom was to admit that he did not know anything. Socrates questioned the status quo of Athenian leadership and was sentenced to death.

The Skeptics vs. the Stoics

Skeptics originated in the 5th century BC in Greece. They trusted in the powers of their direct observations and, as such, can be considered forerunners of the classical Scientific Method. The Skeptic school of thought questioned the validity of claims or new information until verified by testing.

Skeptics believed that absolute certainty of knowledge was impossible.

Stoics, founded in Athens, Greece in the third century BC, believed in the certainty of knowledge that could be attained from pure reason. Knowledge was gained by verifying your experience with your peers and the judgement of your collective community.

The Skeptics in this list are traditionally Sextus the Empirical, Al-Ghazali, Rene Descartes and David Hume.

460-370 BC Hippocrates (Kos, Greece)



The "Father of Clinical Medicine", Hippocrates instituted, among other achievements:

• the systematic study of clinical medicine.
• summing (and publishing) previous medical knowledge from other schools.
• he rejected superstition, legends and belief in the supernatural as a cause of illness.
• he thought that disease was caused by environment, diet and living habits.
• He focused on patient care and prognosis, not diagnosis (Koan School)
• The Hippocratic School defined professionalism in medicine. The physician should always appear 'calm, understanding and serious'.
• Documentation was required as a means of passing knowledge from physician to physician and for teaching and learning.
• Hippocrates used traction, massage, exercise, heat, cold, joint mobilization and promoted risk reduction through lifestyle modification - he was a physical therapist!

129-199 AD Aelius Galen (Pergamum, Turkey and Rome)

The most accomplished physician of the Roman period, Galen was the first to...

• dissect monkeys to make inferences about human anatomy.
• perform numerous surgeries on the brain, the eye and direct nerve ligation.
• use direct observation, dissection and vivisection as training and learning tools.
• distinguish venous from arterial blood.
• Galen published more than 600 written works, which may explain his position among the ancient medical authorities.

160-210 AD Sextus the Empirical (Alexandria, Egypt)

Sextus wrote Adversus Mathematicus, (aka:Against the Mathematicians). He also wrote Against the Professors, Against the Stoics, et al.

Sextus was against the traditionally held beliefs of his time that were often held through tradition or authoritarian teaching methods. He called these ideas 'dogma'. Sextus held that 'dogmatic' theories were barriers to new knowledge.

By dogma, Sextus means the observation or appearance of a cause-effect relationship as a result of a treatment (without benefit of randomization, blinding or control groups).

• Skeptics did not believe that anatomy 'obviously' revealed function.
• Skeptics practiced 'empirical' medicine, based on observation and experience.
• Skeptics rejected 'dogmatic' schools of thought that used established rationale to guide practice decisions.
• Skeptics used trial-and-error as the basis for experimentation.

The Skeptics influenced philosophers Rene Descartes and David Hume, both of whom were important in the history of medical decision making.

The Scientific Method has been called the formal application of the Skeptic philosophy to classical scientific discovery.

Sextus also wrote about the Problem of Inductive Logic, later popularized by David Hume in Europe.

980-1037 AD Ibn Sina or Avicenna (Bukhara, Uzbekistan)

Avicenna is known as the "Father of Modern Medicine". Avicenna wrote The Canon of Medicine which describes, among other ideas:

• experimental medicine
• evidence-based medicine
• randomized controlled trials
• efficacy tests
• rules and principles for testing the effectiveness of new drugs
• modern clinical trials

Avicenna practiced systematic experimentation and quantification. He refuted astrology and alchemy.

He anecdotally pioneered the examination of psychosocial factors by holding the pulse a sick boy and asking him questions of related places, persons and objects. When Avicenna mentioned certain people, namely a young lady from the boy's hometown, the boy's pulse quickened. Avicenna diagnosed 'love sickness' and advised the boy to go tell the girl how he felt about her.

He described steam distillation to separate alcohol from water and invented the refrigerated coil to improve the process.
He was the first to use an air thermometer during his scientific experiments.

1058-1111 AD Al-Ghazali or Algazel (Tus, Iran)



Al-Ghazali is considered the primary Islamic skeptic and his writings may have influenced Rene Descartes.

1561-1616 AD Francis Bacon (London, England)

Bacon established the observational approach of the scientific method which relied on the five senses (seeing, hearing, feeling, tasting, smelling) to gather data.

1564- 1647 Galileo Galilei (Pisa, Florence, Padua, Italy)

Galileo is known as the "Father of Modern Science" for his many achievements in mathematics, physics, astronomy and philosophy. Galileo's own philosophy can be summed up in his statement from his book Il Saggiatore:

Philosophy [i.e., physics] is written in this grand book—I mean the universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written.

It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth.

Galileo's experiments forced him to re-examine previously sacred doctrines that challenged the European status quo and led to his imprisonment. His work forced major changes in the Roman Catholic Church and in the separation of science from philosophy.

1596-1650 Rene Descartes (France and the Netherlands)


Rene Descartes was known as the "Father of Modern Philosophy". He created the Mind-Body Dualism that has influenced modern medicine ever since. Descartes was trying to find out what he could be 100% certain of - he discovered that he could doubt everything, even the existence of his body, but not his mind.

Rationalism vs. Empiricism

Rationalism arrived at the truth through the use of the mind and logic. Descartes stated that mathematics was the only branch where knowledge could be obtained through pure reason, or thought.

Although Descartes was traditionally linked with the Rationalists he believed that knowledge of the physical sciences could be obtained through observation and experimentation.

Empiricists stated that all knowledge could be obtained through observation and experimentation.

Descartes created the Mind-Body Dualism because he found that he could doubt the existence of his body, for instance, as if he were dreaming. He could not, however, logically doubt the existence of his mind.

Descartes concluded his mind and his body were separate entities. He expressed his insight as cogito ergo sum: "I think, therefore I am".

Descartes description of the scientific method emphasized the discovery of knowledge through pure reason, which has largely been superseded by Bacon's empirical approach.

The Mind-Body Dualism, however, has become the dominant paradigm in Western medicine and has led to several sub-specialties of medicine, including Psychiatry and Psychology.

Over 450 years of medical education has taught students to treat patients with mental problems as though there were no physical component; patients with physical problems were treated as though there were no mental/emotional component.


1711-1776 David Hume (Edinburgh, Scotland)

Mr. Hume is best known for his critique of the classic scientific method, the accumulation of knowledge through direct observation. This problem has been called Hume's Problem or, the Problem of Induction.

Hume proposed that we can never know something definitely, like that the sun will rise tomorrow, if our evidence for this prediction is based on the observation that the sun rose yesterday, and the day before that, and the day before that...

Since the whole of science (including 'hard' sciences, like physics) was based on the extremely large number of inductive inferences affirming 'proven' hypotheses (that the sun will rise tomorrow) then Hume's problem was a thorny and embarrassing quandary.

Inductive inferences usualy contain unstated premises: in this case, the unstated premise is that the future will continue to be just like the past.

If it is true that the sun rose yesterday and tomorrow will be just like yesterday then the sun will rise tomorrow. But, with inductive logic true premises do not guarantee a true conclusion - the conclusion is likely, but not certain.

In today's fast-changing world can we guarantee that tomorrow will be like yesterday?

If we could never affirm a thing as being true, then how was it possible that science could (and did) advance?

Hume originally wrote about inductive logic from the perspective of chickens in the barnyard, being fed and housed every day of their lives, accumulating large numbers of independent observations that humans are benevolent guardians of chickens.

The chickens might have been able formulate a theory, through inductive logic, that humans would never hurt a chicken.

Then, one day, came the man with the axe...

1771-1802 Marie François Xavier Bichat (Paris, France)

Known as the father of histology and pathology, he first proposed the concept of distinct tissues. Bichat also proposed the idea that disease processes attack these tissues rather than attacking various organs.

Bichat's contributions are proposed to be among the modern day progenitors of evidence-based medicine by David Sackett, MD.

1783-1855 François Magendie (France)

Magendie is considered a pioneer in physiology by distinguishing between the motor and sensory nerves, specifically in the face. Magendie accomplished these discoveries through vivisection, the dissection of living animals.

Magendie's contributions are proposed to be among the modern day progenitors of evidence-based medicine by David Sackett, MD.

1787-1872 Pierre Charles Alexandre Louis (Paris, France)

Dr. Louis is known as:

• the inventor of the 'numerical method' in medicine.
• He distrusted theory and trusted his observations
• He argued that statistics should be the basis for medical decision-making.
• He claimed that typhoid fever was a specific disease
• He argued against 'bleeding' as a medical treatment.
• His quantitative approach gave medicine certainty in its pronouncements
• He influenced American physicians and the development of American medicine
• He is known as one of the founders of modern day evidence based practice.

1902-1994 Sir Karl Raimund Popper (Vienna, Austria, New Zealand and the USA)

Sir Karl introduced the idea that science (and society) only advances through bold hypotheses, withering criticism and testing.

Testing may lead to the refutation of the hypothesis and promotion of a better hypothesis.

Popper's essential idea is the falsification of hypotheses. Essentially, we never need to prove a theory only, through testing, to show that it cannot be disproven.

PT students who have taken Statistics 101 will recognize Popper's influence from the 'null hypothesis' of statistical inference testing.

Many physical therapy studies attempts to show a (better) difference between two sets of data. The null hypothesis usually asserts that there is no difference. In Hume's problem, the future will always be like the past and the sun will always rise tomorrow. There is no difference between today and tomorrow.

Until a better theory is advanced, the idea that the sun will always rise on successive days is sufficiently valid on which to base predictions (such as, tomorrow will be a good day to go to the beach).

Popper solved Hume's Problem of Inductive Logic (thinking how chickens think) and replaced it with the modern scientific method we use today (thinking how doctors think).

Archie Cochrane (Scotland)

1934- David Lawrence Sackett (Chicago, Illinois) and Canada

Dr. Sackett is a Canadian epidemiologist. He has articulated the role of evidence based medicine within the modern health paradigm, it is:

"the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient.

It means integrating individual clinical expertise with the best available external clinical evidence from systematic research."

Summary

This collection of "fathers" is not complete but attempts to present the history of evidence-based decision-making as a continuous thread, progressing smoothly from the simple to the sophisticated. Of course, history is seldom so cooperative or so clean as I have tried to make it seem here.

These medical and non-medical “fathers” have advanced scientific (and medical) decision-making by questioning the authority of their day and by generating new evidence in place of ignorance.

Why would a book intended for physical therapist managers and workers include a chapter on history and philosophy? I hope that in understanding the origins of science of medical decisions the reader will learn that, many times, the most professional, responsible and honest statement she can make to her patient is "I don't know".

"With the acceptance of science, failure need no longer be fatal.
We can kill off our theories instead of being killed off ourselves"
- Bryan McGee,
Philosophy & the Real World: An Introduction to Karl Popper

Why is skepticism still important?

By the time you retire, it has been said, 100% of what you learn in physical therapy school will be wrong, changed or outdated. The challenge to change professionally will never been more urgent than in the fast-paced world of the 21st Century.

Does the physical therapist use her initial professional training as the basis for all of her decisions or does she question her own knowledge and practice, learning as she goes?

The perspective of this short history is that evidence-based decision making advances through observation, trial-and-error, testing and open dialogue.

From Galen to Galileo (199 AD - 1564 AD) skeptical dialogue almost vanished in Europe and with it the advancement of medicine. The last 30 years have seen dramatic change in physical therapy practice and decision-making that has overturned 450 years of medical tradition and may be a sign of a 'new enlightenment' in rehabilitation.

Recommended Reading

1. Dewitt R. Worldviews: An Introduction to the History and Philosophy of Science. Blackwell, 2004.
2. Magee B. Philosophy and the Real World: An Introduction to Karl Popper. Open Court, 1985.
3. Popper: Conjectures and Refutations. Routledge, 1963.
4. Taleb NN. The Black Swan: The Impact of the Highly Improbable. Random House, 2007.
5. Waddell G. Symptoms and Signs: Physical disease or illness behaviour? BMJ:289, 1984.
6. Waddell G. Chronic LBP, Physiologic Distress and Illness Behavior. Spine: 9(2). 1984.