Funtabulously Frivolous Friday Five 016

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…

Question 1

  • What is Hofstadter’s law?

  • Hofstadter’s Law:

It always takes longer than you expect, even when you take into account 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

Your entry in Wikipedia says that your work has inspired many students to begin careers in computing and artificial intelligence

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.

Douglas Hofstadter

Question 2

  • 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.
Pluralitas non est ponenda sine necessitate

Pluralitas non est ponenda sine necessitate

Question 3

  • What is Hickam’s dictum?

  • The medical counterargument to Occam’s razor

Patients can have as many diseases as they damn well please

  • 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’

Whenever an affirmative proposition is apt to be verified for actually existing things, if two things, howsoever they are present according to arrangement and duration, cannot suffice for the verification of the proposition while another thing is lacking, then one must posit that other thing

Question 4

  • What is Saint’s Triad?

  • Medical eponym used to describe the concurrence of
    • Hiatus Hernia
    • Cholelithiasis
    • 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
    • Hilliard A. A., Weinberger S. E., Tierney L. M. Jr., Midthun D. E., and Saint S. (2004): Occam’s Razor versus Saint’s Triad. N Engl J Med 350:599-603 [Reference] [NEJM]

Question 5

  • 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)

Defects in the belly wall of adults are brought about by pathological damage to fasciae, aponeuroses and tendons, secondary to systemic connective tissue disease abetted by aging [Reference]

  • 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…

Herniosis, the systemic connective tissue disease known to cause diverticulosis and herniae, may be responsible for Saint’s triad. Diabetes, like aging, enhanced herniosis. Further research on the gallbladder wall pathology in patients with cholelithiasis or cholecystitis is needed.

Hernia. 2009 Feb;13(1):29-34. Epub 2008 Aug 14

But in medicine Occam’s razor has often been blunted by the relentless weathering of decades of emotional and physical drizzle in an old and crumpled universe. The osteopath’s absurdly anatomical diagnosis of a left L5/S1 facet joint dislocation imposes a spurious simplicity on a blizzard of dissatisfactions with the world.

I suspect that sometimes the failure to find patterns in the world is not a failure at all.

Kevin Barraclough BMJ 2002;325:171

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Comments

  1. The Michelles says

    We are a group of bored Emergency Physicians from Manly on the other side of Australia where the sun rises over the beach instead of setting over it.
    We constantly giggle at your website, especially on a Friday, but today had a few massive belly laughs as coincidentally Occam’s Razor was the topic of our morning ward round.
    This was particularly interesting as I personally did not understand most of the words on today’s blog (as they contain more than 2 syllables). The Wikipedia definition of Occams Razor is especially daunting.

    Thanks for your inspiring website.

    You have a small but unsophisticated following on the East coast.

    Dr Michelle Chen FACEM
    Dr Michele Franks FACEM

    • says

      Fantastic!
      Great to have some more monosyllabic Aussies joining the LitFL crew.
      I have a couple of purely ‘graphic’ posts for next week so you can put the dictionaries away…

      A ‘small but unsophisticated following‘ is exactly the niche we were aspiring to on the East Coast.

      Keep it real, keep it ‘underground’

      • Michelle Chen says

        Occams Razor Haiku

        If it sounds like Duck
        and it also looks like Duck
        Treat it like a Duck

        By Dr Michelle Chen
        Subcommittee for (almost) monosyllabic FACEMs

  2. says

    It is interesting that you used xkcd. A more recent xkcd had me thinking of Chris Nickson and his toxicology posts.

    http://xkcd.com/749/

    The mouse-over text is something he might enjoy.

    Thank you for the interesting dichotomy/trichotomy/drawing and quartering of Occam’s Razor. I still prefer the Occam version, but I always remember that the word usually is as important as the word simplest. And Occam does have only 2 syllables. :-)

    The simplest solution is usually the correct one.

Comments