Evolution of Medical Reasoning

The challenge to certainty in the face of enormous variability generates an epistemic conundrum. The response to this conundrum has driven the evolution of medicine. The rationalist/allopathic tradition holds that an economical set of principles and facts exists from which each patient’s unique situation can be constructed. There are striking parallels between the allopathic tradition and science. Indeed, it was the ascendency of biomedical science that enabled allopathic medicine to triumph over competitive schools of medicine, such as the empirics in the form of homeopaths. The ascendancy of scientific medicine that allopathics claimed is now institutionalized. However, such economization risks the inverse problem in that there may not be any unique explanation for a particular disease phenomenology, thus giving rise to the possibility of misdiagnosis and mistreatment. Nonetheless, the rationalist/allopathic tradition follows from Aristotle’s metaphysics translated into medical terms by Galen, whose influence is still felt.

Necessary Presuppositions

Metaphysics has been a pejorative term since rejection of the medieval scholastic natural philosophers by the early modern scientists. Since that time, there has been the presumption that “data” speak for themselves and that data are self-evident. Metaphysics was seen as just so much philosophical speculation—science was above that, as was the rationalist/allopathic physician. However, the antipathy to enjoining metaphysics likely is due to a misunderstanding of metaphysics. Any time a theory or hypothesis is invoked, it necessarily goes beyond the data and consequently is a metaphysical exercise. Indeed, responses to the epistemic conundrum are metaphysical choices. Importantly, the metaphysical presumptions shape observations, such as what observations are relevant to a clinical or research question (the a priori problem of induction). Notable examples of metaphysical presuppositions are seen in the development of the cell theory and the derivative pathological–clinical correlations that propelled allopathic medicine.

Variability Versus Diversity in Variety

Making sense of the enormous variety of patient phenomena creates the epistemic conundrum. Is each and every patient taken as a unique entity, or is there an economical set of principles and facts from which each and every patient can be reconstructed? Empiric medicine favors the former, risking Solipsism of the Present Moment. Rationalist/allopathic medicine favors the latter but makes application of knowledge to the individual patient problematic. The conundrum cannot be resolved by simply taking the “average” of all patients or some other measure of central tendency. While it is possible to find the average weight of animals in Dundas, Ontario, it would have little meaning, except perhaps in exceptional circumstance. A central question in statistics is whether the mean (average) reflects the true nature of the phenomenon or does its range (variance)? Assuming the former is greatly enabling in medical decision-making and research but may be misleading.

Epistemic Challenges and the Necessary Epistemic Responses

The practice of medicine is different from the practice of science, although some have argued that medicine must increasingly approximate science if progress in medicine is to be made. There is a myth that science medicine will eliminate uncertainty. Science can remain contingent and pending as individual patients demand action and medical decisions cannot be put in abeyance. Some extrapolate from this difference that science and medicine are fundamentally different, for example, maintaining a distinction between practical and scientific medicine. Yet medicine, practical or otherwise, still requires the use of logic and thus philosophical analysis. Indeed, on closer analysis, medical and scientific reasoning are not fundamentally different—only the consequences are different. Variations of logic to provide utility require an expanded sense of logic. However, with growing appreciation that most living biological systems are chaotic and complex, the logic used in medicine must continue to evolve.

Dynamics

Living organisms, in health or disease, are dynamic, changing over time—physiology. The complexity of living organisms means understanding dynamics may be difficult if inferred only from the static—anatomy. Conflation of anatomy with physiology has led to misunderstanding. The challenge is to reduce the enormous variety of dynamics to an economical set of principles and facts. A conundrum is created in terms of how to organize the dynamics, for example, in terms of the mechanisms of the dynamics or in terms of the outcome of those mechanisms. The same outcome can result from different dynamics; thus, defining the dynamics in terms of outcomes achieves an economization of principles. The outcome could be understood as telos, which refers to the intention or purpose of the dynamics. Yet this is highly problematic and could underlie medical and scientific misreasoning. Furthermore, chaos and complexity present a great challenge to understanding dynamics.

The False Notion of Intention, Choice, and Inhibition

A ubiquitous metaphysical presumption in medicine, particularly in neurology, derives from Aristotle’s notion of contraries. The variety within a domain of phenomena can be considered as some mixture of a few components. For example, a grayscale continuum is not an infinite number of shades of gray but rather varying mixtures of black and white. This metaphysical presupposition provides an enormous economization of principles critical to allopathic medicine and research. Epistemically and ontologically, this results in methodological, ontological, and theoretical reductionism. The presupposition leads to one-dimensional push–pull dynamics. In neurology, this metaphysical presupposition resulted in a notion of hierarchy in the physiology of the nervous system affected by inhibition. This led to notions of potentiality, intention, and choice creating problematic notions and misunderstandings. For example, the popular notion that the role of the frontal lobes prevents antisocial behavior, suggesting its potentiality, leaves unanswered the question of what is inhibited by the intact frontal lobe?

The Meaninglessness of the Mean

The mean (average) or other central tendencies of a set of data is an internal construct that does not necessarily reflect reality. It is possible to determine the central tendency from any arbitrary collection of data as long as they vary on the same dimension. Even if applied to a relevant sample of data, the central tendency may be a poor reflection of data. A virtually infinite number of different collections of data may have the same central tendency and variance. This has very important implications when reasoning from studies reporting means and standard deviations. The same concerns apply to medians as the central tendencies and quartiles as the variability. When translating studies to the individual patient, the cumulative percentage (probability) function may be more helpful. There is a strong inclination to attribute some ontological status (reality) to measures of central tendency that can be misleading.

Medical Epistemology

Deductive approaches in medical decision-making have an air of certainty borrowed from philosophical deduction, as for example, in the hypothetico-deductive approach. However, deduction, although certain, is limited because it cannot contribute to new knowledge other than proving some claims to knowledge as false (using modus tollens). Syllogistic deduction requires modification to gain utility, such as the partial and practical syllogisms. However, these forms are logically invalid in that they do not ensure certainty in the conclusions. The partial syllogism can be rendered more certain by the use of probability. However, the necessity of a medical decision requires dichotomization of the continuous probability variable. A cutoff threshold applied to the probability is necessary to enable a dichotomous decision, such as whether to treat or not treat a patient. The practical syllogism introduces the notion of cause and effect, which also may influence medical decisions, although often in a counterproductive manner.

What Are We to Make of Reasoning in Modern Medicine?

The suasive power of clinicians depends on the projection of certainty; with that suasive power, responsibilities to the patient have not diminished even if the clinicians’ authority has. Certainty is reflected in understanding, which is more than knowledge. Understanding allows reasoning beyond the specifics of knowledge, beyond the particulars. The variation in human manifestations represents either variation or diversity. In variation, all specific instances are variations on some canonical form. Diversity holds each instance as an entity unto itself. The epistemic choice of variety as variation or diversity determines medical reasoning. Biomedical research is confronted with the same challenges. The resort is to a special form of logic and epistemology that is organic, responding to needs, and synthetic, the product of humans. This evolutionary logic embraces a necessary use of logical fallacies. Science requires these fallacies, and thus scientism is limited and cannot replace medical reasoning.

A Calling to Be Better than Ourselves

It is difficult to name a profession with great authority with so little accountability compared to physicians who have finished supervised training. US Supreme Court justices have lifetime appointments and removal from office is exceedingly rare, nevertheless they are always under the public eye. Analyses demonstrate that the threat of malpractice is a poor tool at best to enforcing best practices. Attempts to establish peer review when used rarely address issues of medical reasoning. Furthermore, the physician shortage often leads to perhaps excessive tolerance for physicians’ actions. Accountability is a clinician’s ethical responsibility by virtue of the ethical principles of respect for autonomy, obligation to beneficence, avoidance of maleficence, and justice. These principles underlie the informed consent that is the basis of the clinician–patient relationship. In the end, it is only the personal commitment of the clinician to the patient that best guarantees that both will be served well.