Epistemology and Medicine: An Overview

Aristotle understood that the fundamental properties of knowledge were themselves a worthy subject of study. How do fundamental considerations of knowledge and uncertainty influence medical decision making and treatment? Why is a constant awareness of the imperfection of the data at hand essential for the safe and effective delivery of medical care?

Epistemology is the branch of philosophy that deals with questions of knowledge. What is knowable in any given situation? How does one come by knowledge? How reliable is this knowledge? What conclusions and inferences can safely be drawn from this knowledge?

 

All of these questions bear directly on the process of medical decision-making as well as on the art of medical therapy. The first and perhaps the most important epistemological problem in the nature of pain itself. Since pain is a first person perceptual phenomenon, statements about it mad by a sufferer are incorrigible. I cannot know what you feel. I can only know what you tell me. I can take your pulse rate and measure your blood pressure, which may both be normal. I can observe you and not the lack of sweating, grimacing or wincing. I can do a complete physical examination and an extensive battery of laboratory tests and imaging studies, all of which may fail to detect any conditions commonly associated with pain, but I cannot make any meaningful statements about whether or not you are in fact in pain. Indeed we have begun to unlock the pathophysiology of certain central pain states where all of the above seem to be true and yet the patient is in pain.

 

Other epistemological problems relate to the uncertainty inherent in all medical knowledge. I remember my first day of medical school seated in a very old and steeply pitched medical theatre (lecture hall). The Dean of Students stood solemnly in the pit of the theatre and announced, “ We on the faculty have a serious problem. We know that half of what we teach you in the next four years will turn out to be false. We just don’t know which half!”

 

Even if you leave this general question aside for the moment, there is the undeniable imperfection with all of the patient based data upon which we base our diagnosis. There are very few pathognomonic signs in medicine. Every piece of data is potentially compatible with multiple diagnoses. Every laboratory test has a false positive and a false negative rate associated with it. I have gone so far as to tell my patients that I can never really tell anyone with absolute certainty what is really wrong with them. I can only make probabilistic statements. In most cases these probabilistic statements have a high degree of reliability, but the uncertainty inherent in them can never be completely ignored. In subsequent pages we will explore some of the more important epistemological issues such as the restriction effect and game theory in an attempt to show you how we try to minimize uncertainty and maximize positive outcomes.

(For a lighthearted look at epistemology see the following from Rocetboom.)

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