Feeling a bit wound-up…feeling a bit frazzled by Friday? Why not relax and unwind with some medical trivia…
This week we enter the domain of the medical nerd and medical uber-geeks and try to tackle some philosophical questions on Occam’s Razor, Hickam’s dictum, Hofstadter’s law and the inter-relation of these theories on diagnostic parsimony…
What is Hofstadter’s law?
- Hofstadter’s Law
- Douglas Hofstadter (1945-) is an academic who thinks a lot about thinking and self-referentiality (if such a word exists) and specialises in the recursive and paradoxical…and has “no interest in computers”
- He wrote the Pulitzer-prize winning book Godel, Escher, Bach: An Eternal Golden Braid
- His Wikipedia entry contains this self-referential excerpt when he replied to a question by Deborah Solomon
The entry is filled with inaccuracies, and it kind of depresses me.
Why don’t you fix it?
The next day someone will fix it back.
What is Occam’s Razor?
- The simplest solution is usually the correct one
- Occam’s razor is inherently heuristic (rule of thumb) and not considered an irrefutable principle of logic.
- It is attributed to William of Occam (a 14th century English logician and Franciscan friar)
- Alternate descriptors include:
- Plurality should not be posited without necessity (pluralitas non est ponenda sine necessitate)
- Entities must not be multiplied beyond necessity (ntia non sunt multiplicanda praeter necessitatem)
- Law of Parsimony and ‘Diagnostic parsimony‘
- In medical terms it is often translated into the law of diagnostic parsimony – to try to come up with a ‘unifying’ diagnosis that can explain all the patient’s problems (i.e. to invokeOccam’s Razor)
- Diagnostic parsimony advocates that when diagnosing a given injury, ailment, illness, or disease a doctor should strive to look for the fewest possible causes that will account for all the symptoms.
What is Hickam’s dictum?
- The medical counterargument to Occam’s razor
- Attributed to Dr John B Hickam (Duke University and Chairman of medicine at Indiana University)
- The actual process that occurs when diagnosing a patient is a continuous flow of hypothesis and testing of that hypothesis, then modifying the hypothesis, and so on…In the context of this method, the principle of Hickam’s dictum asserts that at no stage should a particular diagnosis be excluded solely because it doesn’t appear to fit the principle of Occam’s razor.
- The principle of Occam’s razor, or parsimony, does not demand that the diagnostician necessarily opt for the simplest explanation, but instead guides the medical practitioner to seek explanations, without unnecessary additional assumptions, which are capable of accounting for all relevant evidence.
- It is often statistically more likely that a patient has several common diseases, rather than having a single rarer disease which explains their myriad symptoms
- It holds similar principles of Walter Chatton’s ‘anti-razor hypothesis’
What is Saint’s Triad?
- Medical eponym used to describe the concurrence of
- Hiatus Hernia
- Diverticular Disease
- Named after the British Surgeon – Prof C. F. M. Saint (founder of the first South African medical school)
- Saint emphasized the importance of considering the possibility of multiple separate diseases in a patient whenever his or her history and the results of the physical examination were atypical of any single condition
- Thanks to philosophical rantings, Saint’s triad has been used as an example of Hickam’s dictum. This triad has no known pathophysiological relationship, nullifying the usefulness of Occam’s razor
What is herniosis?
- Herniosis is proposed to be a systemic connective tissue disorder associated with a predilection to develop diverticulosis, vaginal prolapse and abdominal herniae
- First postulated by the anatomist Arthur Keith (1866-1955)
- The herniosis theoryhas undergone a resurgence in recent times and the Occamites now challenge the Hickamic principles defining Saint’s triad with two new potentially unifying pathophysiological theories of diagnostic parsimony…
- Obesity – associated with gallstones, hiatus hernias and diverticular disease
- Herniosis – Is herniosis the single etiology of Saint’s triad? (well 2 out of 3 ain’t bad!)
Hernia. 2009 Feb;13(1):29-34. Epub 2008 Aug 14