WEBVTT

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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 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 between
autopsies of fever victims

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and new fever patients,
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.