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Flora Lichtman: Imagine for a moment that
you are not you. That you're a tick. You live
here in Van Cortlandt Park in the Bronx, and
you're an adult, so that makes you about the
size of George Washington's nose on a quarter.
What would life be like? How would you make
sense of your environment?
In the late 1880s, Estonian biologist Jakob
von Uexküll played out this thought experiment.
He distilled tick life into three parts. First,
the tick climbs up to a blade of grass and
waits for prey. Second, when prey walks by,
like a mammal, it senses it. We now know that
the tick does this through the carbon dioxide
in the mammal's breath.
Third, in Uexküll's conception, the tick
falls off the blade of grass, it drills its
mouth into whatever it's landed on. If it
feels warmth, it takes a drink. If cold, it
climbs back up to the blade of grass to wait
again.
In this thought experiment, all of the tick's
knowledge comes from its senses. Would you
say the same is true for humans?
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Flora Lichtman: When we systemically collect
and analyze sensory data, we're doing science.
This is the concept of empiricism, that knowledge
comes primarily through observations through
our senses, not just from thinking.
But humans, unlike ticks, are limited to sensory
data we can collect only through our bodies.
Because we can build tools that let us see
things our eyes could never pick up, eavesdrop
on sounds our ears could never hear, and travel
to environments our body could never survive.
Scientists take those observations and transform
them into a scientific body of knowledge.
Now the skillset that scientists use to do
this is something we're calling knowledge
sense, and we're going to hear a lot more
about that coming up. We're also going to
talk about what science is.
How would you define science?
Chanda Bennett: Science is the process of
developing hypotheses, asking questions, identifying
methods to answer that question, and assessing
the information that you gather. Science is
part of everything that we do every day.
I think some of the stereotypes about science
may impede people from really understanding
and engaging with science. You have this stereotype
of what a scientist is, and we need to just
shatter that. You have a stereotype of what
science is and who science is for, and it's
for everyone, and anyone with an interest
can develop their scientific sense.
Flora Lichtman: Massimo Pigliucci is a philosopher
of science, which means it's his job to think
about what science is.
Massimo Pigliucci: One thing you want to think
about when you're trying to understand science
is that it is, first of all, empirically based.
There has to be some kind of observation,
experiment, factual matter that enters into
your reasoning. Otherwise, you're not doing
science.
Tammy Lewis: People do science. Science doesn't
do itself. There's no machine that you can
put stuff in that's going to be plopped out
the other end that's purely objective.
Flora Lichtman: Humans have the capacity to
take in information and learn something new
about the world. But, as most of us also know,
probably from personal experience, we also
have the capacity to hold onto ideas because
we believe them to be true, because we want
them to be true.
Our beliefs come from our lives, from our
experience of the world, but not necessarily
from data, or certainly not from controlled
experiments. In fact, evidence suggests that
when we get new data that conforms to our
worldview, we are more likely to accept it.
There's a term for this. It's confirmation
bias, and here's a legend on just this subject.
The year is 550-ish BC. We're in Greece, and
this guy is a powerful cult figure. Pythagoras
and his disciples have a mystical reverence
for numbers. One of their beliefs is that
the only numbers that exist are either whole
numbers or the ratio of whole numbers. These
are known as rational numbers.
Enter Hippasus of Metapontum. He's contemplating
the diagonal of a one-by-one box and figures
out that the diagonal length is the square
root of two. He then proves that no ratio
of two rational numbers gives you the square
root of two. In other words, he discovers
that irrational numbers exist.
His finding demolishes the Pythagoreans' worldview,
so what do they do? The Pythagoreans drag
him out to sea and drown him for the discovery.
Or so the legend goes.
In this story, the Pythagoreans held a belief
that was impenetrable to new observations.
That's not a model for science. On the other
hand, skepticism is a crucial part of science.
If new data overturns old beliefs, that's
the scientific machine working well.
Tammy Lewis: We should always have some skepticism
around science, and we shouldn't just always
say, "Oh, well the scientific study said it,
it must be true." Right? Even science itself
as a process says be skeptical. We don't just
take one study and say, "Oh, we found this,
it must be true," but we in fact replicate
each other's studies so that we see, did what
Flora found in this study, if I do that again,
am I going to find the same results?
If I do, I say, "Oh, great, so that might
be true." But then somebody else does it again,
and the more people who replicated it and
the more that we find the same thing, then
we have some confidence in that scientific
law or truth.
Justin Garson You might say, "Well what's
so good about science if we can't be absolutely
sure that our theories are true?" What most
of us want out of life is reliable theories.
We want our beliefs to be reliable. We want
our beliefs to be likely. They don't have
to be absolutely certain.
But when I'm trying to decide, for example,
whether I should cut red wine out of my diet
or whether to drink more of it, I want to
know that the people who produce this kind
of data, and the methods that they're using
to produce this kind of data are reliable.
I want to know that I'm resting on what scientists
now take to be the most likely theory.
Flora Lichtman: What are the mechanisms in
science that help ensure reliability?
Massimo Pigliucci: There's peer review. So
there is a series of sociological interactions
among scientists. If I am a scientist and
I want to publish a new piece of research,
what do I do? I submit it to the editor of
a technical journal, the editor looks at it.
If it's interesting enough, it sends it out
to a number of reviewers who are scientists,
peer scientists in the same area. Those people
look at it, and they give me feedback, and
eventually the paper gets accepted, and it
becomes part of the edifice of knowledge that
science builds.
Justin Garson: We think of good scientific
theories or good scientific disciplines as
constantly revising themselves in light of
new evidence. Science isn't a finished and
done project. It's not a set of dogmas or
doctrines that you have to either accept or
reject once and for all. Science is always
changing, our theories and hypotheses are
changing in light of the kinds of evidence
that we're constantly obtaining. Science is
an adventure in this way.
Charles Liu: This, perhaps more than any other
way, is a way of establishing a human legacy,
a chain that goes from the past to the present
and into the future. It is a great thing.
It is marvelous. It is fun.
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