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Can you outsmart the fallacy that fooled a generation of doctors? - Elizabeth Cox

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    Oh the humanity!
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    Ah... humanity...
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    It’s a trainwreck,
    but I can’t look away.
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    It’s 1843, and a debate is raging
    among physicians
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    about one of the most common
    killers of women: childbed fever.
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    Childbed fever strikes
    within days of giving birth,
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    killing more than 70% of those infected—
    and nobody knows what causes it.
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    Obstetrician Charles Meigs has a theory.
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    Having observed abdominal inflammation
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    in patients who go on
    to develop the fever,
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    he claims this inflammation
    is the cause of childbed fever.
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    Much of the medical establishment
    supports his theory.
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    Oh, come on!
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    They really leave me no choice
    but to teach them some skepticism.
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    That’s better.
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    Now, Meigs, your argument is based
    on a fallacy— the false cause fallacy.
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    Correlation does not imply causation:
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    When two phenomena regularly occur
    together,
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    one does not necessarily
    cause the other.
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    So you say women who have inflammation
    also come down with childbed fever,
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    therefore the inflammation
    caused the fever.
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    But that’s not necessarily true.
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    Yes, yes, the inflammation comes first,
    then the fever,
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    so it seems like the inflammation
    causes the fever.
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    But by that logic, since babies
    usually grow hair before teeth,
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    hair growth must cause tooth growth.
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    And we all know that’s not true,
    right?
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    Actually, don’t answer that.
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    A couple of different things
    could be going on here.
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    First, it’s possible that fever
    and inflammation are correlated
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    purely by coincidence.
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    Or, there could be a causal relationship
    that’s the opposite of what you think—
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    the fever causes the inflammation,
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    rather than the inflammation
    causing the fever.
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    Or both could share a common
    underlying cause you haven’t thought of.
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    If I may, just what do you think
    causes inflammation? Nothing?
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    It just is? Really?
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    Humor me for a moment in discussing
    one of your colleague’s ideas—
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    Dr. Oliver Wendell Holmes.
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    I know, I know,
    you don’t like his theory—
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    you already wrote
    a scathing letter about it.
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    But let’s fill your students in, shall we?
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    Holmes noticed a pattern:
    when a patient dies of childbed fever,
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    a doctor performs an autopsy.
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    If the doctor then treats a new patient,
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    that patient often comes
    down with the fever.
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    Based on this correlation
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    between autopsies of fever victims
    and new fever patients,
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    he proposes a possible cause.
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    Since there’s no evidence that the autopsy
    causes the fever beyond this correlation,
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    he doesn’t jump to the conclusion
    that autopsy causes fever.
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    Instead, he suggests that doctors
    are infecting their patients
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    via an invisible contaminant
    on their hands and surgical instruments.
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    This idea outrages most doctors,
    who see themselves as infallible.
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    Like Meigs here, who refuses
    to consider the possibility
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    that he’s playing a role
    in his patients’ plight.
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    His flawed argument doesn’t leave any
    path forward for further investigation—
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    but Holmes’ does.
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    It’s 1847, and physician Ignaz Semmelweis
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    has reduced the number
    of childbed fever deaths
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    in a clinic from 12% to 1%
    by requiring all medical personnel
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    to disinfect their hands after autopsies
    and between patient examinations.
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    With this initiative, he has proven
    the contagious nature of childbed fever.
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    Ha!
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    It’s 1879, and Louis Pasteur
    has identified
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    the contaminant responsible
    for many cases of childbed fever:
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    Hemolytic streptococcus bacteria.
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    Hmm, my fries are cold.
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    Must be because my ice cream melted.
Titel:
Can you outsmart the fallacy that fooled a generation of doctors? - Elizabeth Cox
Sprecher:
Elizabeth Cox
Beschreibung:

View full lesson: https://ed.ted.com/lessons/can-you-outsmart-the-fallacy-that-fooled-a-generation-of-doctors-elizabeth-cox

It's 1843, and a debate is raging about one of the most common killers of women: childbed fever— no one knows what causes it. One physician has observed patients with inflammation go on to develop childbed fever, and therefore believes the inflammation causes the fever. What's the problem with this argument? Elizabeth Cox explores the false cause fallacy and how to dissect claims with skepticism.

Lesson by Elizabeth Cox, directed by TOGETHER.

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Video Language:
English
Team:
TED
Projekt:
TED-Ed
Duration:
05:14

Untertitel in English

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