Picture of Lester LiaoLester Liao
Western University
Class of 2016


Medicine is often thought of as a matter of science. Experiments are conducted and cumulative evidence is then applied to best clinical practice. While this is certainly true, there is a lack of appreciation of what goes into the process of medicine. There are numerous assumptions that take place in medicine, including our method of experimentation and interpretation of findings. This is where philosophy comes in, to balance the science of medicine. The philosopher of science, Samir Okasha, states that “part of the job of philosophy is to question assumptions that scientists take for granted (1).” With no knowledge of the groundwork of medicine, or our assumptions, we may find in the end that we do not even know why we practice as we do. By looking into the nuts and bolts of how philosophical concepts drive our everyday decisions, this piece will hopefully raise awareness of the necessities – and pitfalls – of these “mental shortcuts”.

A generic illustration highlights the role of philosophy. Let us say medicine shows me that process A leads to outcome B. The philosophy of science causes me to question my assumptions and consider how I know my epistemological (a term used to describe theories about the nature of knowledge) process for coming to this conclusion is valid. This epistemological process can include various questions. Did I see A lead to B? Why is the empirical method sufficient for this study? Does it follow that all A’s lead to all B’s? Does A always lead to B? In medicine we tend to focus solely on the A to B and forget all the other elements involved in going from A to B in the real world. Attending to the complexity of the ‘in-between’ requires philosophy.

Philosophers of science sometimes use thought experiments to foster this kind of complex thinking. For example, if we see drug A work in person B, we may not assume that drug A (assuming it is indeed still the same drug) will work in person C. This employs the concept of generalizability. Physicians unknowingly apply this concept on a daily basis, such as when prescribing antibiotics – that have not been tested in children – to their pediatric patients. Although a harmless action in most cases, ignorance of this assumption can, and will, lead to disastrous outcomes. Generalizability is not an element of a scientific experiment in itself, it is a philosophical mode of questioning how science can make a pragmatic difference. By looking critically at generalizability we can begin to see that philosophy gets at the foundations of how we practice medicine.

Two other philosophical principles that can be readily applied to medicine are the falsifiability of theories (any valid theory must be testable) and parsimony (the simplest answer is best). These principles shape our entire approach to research in medicine. Empirical research is based precisely on the belief that outcomes inconsistent with a theory should cause the theory to be questioned. For example, if it is posited that certain allergic food reactions are IgE-mediated, attenuating the IgE response should lead to a decreased reaction. If therapies that eliminate IgE antibodies or convert IgE responses to IgG responses are tested but allergic food reactions are equally severe, this accumulates evidence to falsify the IgE-mediated theory. Furthermore, if one mechanism can explain a problem, it is more readily accepted than three of four separate mechanisms. For example, if a newborn child has slanted palpebral fissures, hypotonia, excessive skin at the nape of the neck, and a ventricular septal defect, it is more likely that he has Down syndrome than four separate issues. Philosophy in science directly impacts the approach to evidence that is then translated into practice.

A highly influential work in this area is The Structure of Scientific Revolutions by Thomas Kuhn. Kuhn argues that in any era, normal science is about fitting into the paradigm or way of thinking of that time. Discoveries inconsistent with the paradigm are puzzles to be solved, not ways to test the validity of the current paradigm (2). For example, if we discovered an ancient organism that has been actively producing new organisms for millenia, the evolutionary paradigm could be challenged. Yet, without a paradigm shift, evolutionists would find ways to explain how the new finding fits under evolution instead of how it challenges evolution or may warrant further investigation. This resistance to paradigm shift is exacerbated by peer pressure that denigrates the new theory and pressure to do research agreeable to funding parties. Kuhn showed how such trends have repeated, over and over, across centuries of scientific thinking. Collectively these pressures can impede genuine, inquisitive science. The philosophy of science shows us that even our interpretation of results yielded by the empirical method is influenced by our current paradigm or ‘normal science.’ Practically this means we must not immediately reject challenges even of the evidence-based paradigm or other reigning theories of our day.

There are numerous issues that philosophy raises in terms of medicine; the aforementioned are but a few. Nonetheless it is clear that philosophical questions form the bedrock on which we build the entire practice of medicine. If we are to be serious about medicine, we should be serious about asking why we practice as we do. People will come to different conclusions for the various questions posed by philosophy, but it hardly follows then that a right answer cannot be known. Ultimately, philosophy can guide us to better understanding of why we practice medicine the way we do.


1. Samir Okasha, Philosophy of Science: A Very Short Introduction (New York: Oxford University Press, 2002), 12.

2. Thomas Kuhn, The Structure of Scientific Revolutions: 50th Anniversary Edition (Chicago: University of Chicago Press, 2012), 144.