Oh the humanity!

Ah... humanity...

It’s a trainwreck,
but I can’t look away.

It’s 1843, and a debate is raging 
among physicians

about one of the most common 
killers of women: childbed fever.

Childbed fever strikes 
within days of giving birth,

killing more than 70% of those infected—
and nobody knows what causes it.

Obstetrician Charles Meigs has a theory.

Having observed abdominal inflammation

in patients who go on 
to develop the fever,

he claims this inflammation 
is the cause of childbed fever.

Much of the medical establishment
supports his theory.

Oh, come on!

They really leave me no choice 
but to teach them some skepticism.

That’s better.

Now, Meigs, your argument is based 
on a fallacy— the false cause fallacy.

Correlation does not imply causation:

When two phenomena regularly occur
together,

one does not necessarily 
cause the other.

So you say women who have inflammation
also come down with childbed fever,

therefore the inflammation 
caused the fever.

But that’s not necessarily true.

Yes, yes, the inflammation comes first,
then the fever,

so it seems like the inflammation 
causes the fever.

But by that logic, since babies 
usually grow hair before teeth,

hair growth must cause tooth growth.

And we all know that’s not true,
right?

Actually, don’t answer that.

A couple of different things 
could be going on here.

First, it’s possible that fever 
and inflammation are correlated

purely by coincidence.

Or, there could be a causal relationship
that’s the opposite of what you think—

the fever causes the inflammation,

rather than the inflammation 
causing the fever.

Or both could share a common 
underlying cause you haven’t thought of.

If I may, just what do you think 
causes inflammation? Nothing?

It just is? Really?

Humor me for a moment in discussing
one of your colleague’s ideas—

Dr. Oliver Wendell Holmes.

I know, I know, 
you don’t like his theory—

you already wrote 
a scathing letter about it.

But let’s fill your students in, shall we?

Holmes noticed a pattern: 
when a patient dies of childbed fever,

a doctor performs an autopsy.

If the doctor then treats a new patient,

that patient often comes 
down with the fever.

Based on this correlation

between autopsies of fever victims
and new fever patients,

he proposes a possible cause.

Since there’s no evidence that the autopsy
causes the fever beyond this correlation,

he doesn’t jump to the conclusion 
that autopsy causes fever.

Instead, he suggests that doctors 
are infecting their patients

via an invisible contaminant 
on their hands and surgical instruments.

This idea outrages most doctors, 
who see themselves as infallible.

Like Meigs here, who refuses 
to consider the possibility

that he’s playing a role 
in his patients’ plight.

His flawed argument doesn’t leave any 
path forward for further investigation—

but Holmes’ does.

It’s 1847, and physician Ignaz Semmelweis

has reduced the number 
of childbed fever deaths

in a clinic from 12% to 1% 
by requiring all medical personnel

to disinfect their hands after autopsies
and between patient examinations.

With this initiative, he has proven
the contagious nature of childbed fever.

Ha!

It’s 1879, and Louis Pasteur 
has identified

the contaminant responsible 
for many cases of childbed fever:

Hemolytic streptococcus bacteria.

Hmm, my fries are cold.

Must be because my ice cream melted.