Vsauce! Kevin here, with a message about your
online existence.
Social media is a venomous snakepit of verbal
diarrhea and keyboard garbage because no one
can agree on what knowledge is actually knowledge.
No matter what the post, or video, or tweet,
or argument is about, no matter what side
they’re on, no matter what they believe,
someone else knows they’re wrong. They don’t
know anything. How can two people both be
so confident that they know something when
they’ve reached totally different conclusions?
Obviously both can’t be right.
Right?
What’s weird, is that it seems pretty simple
to know something. I mean… you just know
it. You know it because you have some kind
of relevant experience, or you know someone
who does and they transferred that knowledge
to you. Or maybe you’ve read something you
trust, or you know that what an expert in
a particular field says is valid. However
it comes to you, that information is an accurate
description of the way the world is.
That’s knowledge. Right? Wr- Sometimes.
The way we tend to think about knowledge is
in terms of “justified true belief,” a
concept that goes back to Plato’s dialogue
between Socrates and Theaetetus in 369 BC…
and was actually refined and codified by 20th
century philosophers. It’s a little more
modern than it seems, but it’s exactly what
it sounds like: to know something, you need
to have justification for it. What sort of
evidence tells you it’s right? Is there
enough of it? Are the odds in its favor?
And it needs to be true. Is it reality for
you and for others? Does it really hold up
to scrutiny? Truth is pretty weird in that
it’s metaphysical -- it’s about how things
are, not necessarily what we see. We don’t
even have to verify something for it to be
true. Quick, pick heads or tails! Go! I’m
never, ever going to look at the result of
this coin flip, but half of you predicted
the true outcome.
And then you’ve got to believe it: and you
have to recognize it as being true and justified.
Look. Here's a very simple example. You look
at a clock to find out the time, because...
clocks tell time. You're justified in thinking
a clock is going to tell you the time. The
clock says 3pm, which you believe because
it's always been right before and this is
what clocks do. It's true because it's actually
3pm. So, congratulations, you KNOW it's 3pm.
All of this makes sense. What I’ve just
described is a formal examination of what
we all do pretty much all the time.
BUT.
I can prove your justified true belief, your
knowledge, can be an illusion.
For thousands of years the understanding of
what knowledge is was considered etched in
stone. Case closed. Until. In 1963, philosopher
Edmund Gettier wrote a short, 3-page paper
that completely smashed the justified true
belief simulation. It was such a shift in
how we think about knowledge that philosopher
Alvin Plantinga said in 1993 that, “Knowledge
is justified true belief: so we thought from
time immemorial. Then God said, ‘Let Gettier
be’; not quite all was light, perhaps, but
at any rate we learned we had been standing
in a dark corner.”
How? Gettier claimed that we can satisfy all
three of those conditions and still not actually
know something.
Let’s revisit our clock example. We looked
at a clock that read 3PM and had knowledge
it was 3PM because it satisfied Plato’s
Justified True Belief definition. But. What
if the clock was broken and stuck at 3PM?
Do you actually know the time from looking
at a broken clock even if it’s accidentally
correct? No. Like "N" "O" no. Not "K" "N"
"O" "W" know. That is Justified True Belief
without Knowledge. That is a Gettier Problem.
Or think of it like this: there is a cat in
this YouTube video.
HOWDY! Sheriff Cat here. I just mosey’d
on into this two-bit town to restore a bit
of order. Y’see, this here wobblin’-jawed
tenderfoot’s been yarnin’ the hours away
with too much mustard and I aim to set things
straight before the whole corral turns into
a bag of nails.
I haven’t been outside in four months.
Anyway, there’s a cat in this YouTube video.
You know there’s a YouTube video because
you’re watching me record it. You’re on
YouTube right now. You’re looking right
at Sheriff Cat. You’re justified in thinking
there’s a cat in this video, you can decide
it’s true with confidence, and you believe
what you’re seeing. Everything here adds
up.
And you were right. There has been a cat in
this video this whole time -- you were just
right for the wrong reasons. And yeah, you
were right, but… did you know it? Is THAT
knowledge? Is that knowledge, Luna? Go figure
it out. Go figure out what knowledge is.
No! Of course it’s not -- you knew NOTHING!
You had a justified true belief, it was accurate,
but... it wasn’t. So even when you’re
right, how do you know you’re not actually
wrong? This calls into question the scientific
method, what we think we know about the natural
world, EVERYTHING -- given the ease and prevalence
of Gettier problems, we can’t possibly know
ANYTHING, RIGHT?
*phone rings*
Hello?”
Wrong. Well, mostly wrong. This is how it
actually works, okay? As scientists, we have
a hypothesis, we wonder if something is true
or not true, we propose an experiment. If
the experiment supports the hypothesis, then
we say, "Well, maybe my idea was true, but
I could be biased. Maybe there was a flaw
in my experiment. Maybe the electrical current
had a glitch in the midpoint of taking data."
Yeah, but that’s exactly the kind of uncertainty
I’m talking about.
So I do the experiment again. I try to design
a different kind of experiment to test for
the same idea. I get a colleague of mine to
test it. I get them to come up with a new
kind of experiment. I get a competitor of
mine to try to show that I'm wrong with an
experimental design of their own. And if all
those experiments give approximately the same
answer, because there will be statistical
variation, if it gives approximately the same
answer, we're onto something.
Okay, so, in science you take what seems to
be knowledge and then start to eliminate all
those other possibilities to distill what
you think you know.
A new truth is emerging in the methods and
tools of science as they are applied to that
question, right? So we learn Earth goes around
the sun. That's not going to later on be shown
to be false ever. Ever. We got that one. Now,
you can ask more refined questions, okay?
What kind of orbit does it have? Is it a perfect
circle? It's a good approximation, but it's
not exactly right. So you can ask deeper questions.
Yes, it does go around the sun. What kind
of a circle is it? Is it a squashed circle?
Is it elongated? And you keep doing this,
and what you end up doing is refining the
answer to the question to a level that satisfies
your needs in the moment.
Yeah, that’s how knowledge builds and expands.
So maybe it’s not so much about what we
don’t know, as what we keep finding out.
So you can say, "Will we ever know anything?"
Yes, we know a lot of things. "Will we ever
know anything perfectly?" Well, there are
certain things you can ask where you're just
counting things. Yes, you can know perfectly.
There's certain crystals where we know exactly
where all the atoms are, and we can count
them, so we know exactly how many atoms there
are in certain crystals. Yes, there are certain
answers that are precise, but if it involves
a measurement? No, it can be ever more refined,
but there could be a point where more refinement
just doesn't matter to the aspect of the answer
that you're seeking. So, in science, we are
perfectly content when multiple experiments
agree, even if the philosopher isn't. Even
if the philosopher is distracted by the possibility
that there might be a deeper truth lurking
within the data that we have accumulated.
I don't have a problem with that. I don't
have a problem.
Yeah, I guess we can hit a point where we
know as much as we want to or need to. And
when we hit the end like that we move on to
something else.
Science is a continuous journey through the
maze of nature, but not all information is
equally uncertain. That's my only point here.
We know how to fly. We know how wheels work
and all the other machines in physics. We
know how electricity works. We can use a phone.
I got an old-fashioned phone here. It's why
this works. To say, "We can't really know."
We do know. That's why you're living longer.
That's why so many things are different about
your life today than how your ancestors lived.
Because the methods and tools of science have
been applied to questions that curious people
have asked, for the most part, for the betterment
of society and for civilization itself. So,
no, I'm not going to wallow in some prospect
that we can never know anything. No. We do.
And if you want to think that way, just move
back to the cave, because that's really where
you belong.
Yeah, I like indoor plumbing. Hey Neil, while
I’ve got you -- there’s a question that
has been killing me for years. It's very,
very important.
You've got a question after all that? Okay.
What is it?
Okay, ready? Is a hot dog a sandwich?”
I have vowed many years ago to never get into
an argument with someone on the definition
of a word. All kinds of people love doing
this. I remember growing up. Is it a gum,
or is it a candy? Is it light, or is it less
filling? I'm saying no, I'm not going there,
because ideas matter to me more than the words
we come up with to describe them.
Okay. But I need to know. We need to categorize
this.
But just because your brain is... Not yours,
but all of our collective brains want to categorize
things, and if something spills out of one
category, we fight about where it belongs.
I'm saying no, I'm not having that fight.
I'm not having that fight. In fact, if you
want to go there, just invent a new category.
Call it the hot dog category. Okay, it's not
a sandwich, it's a hot dog. I'd be happy with
that. Otherwise, no, I'm not spending time
arguing this.
Please, Neil... Please...
Is it a non-bread food sitting between two
surfaces of bread? It's a sandwich. Duh. Bye.
Haha!There you have it. Well, this wasn't
plugged into anything... Anyway
The Gettier problem exists -- and knowledge
is a lot more complicated than it seems.
Excuse me, Sheriff Cat. Happy trails!
Sometimes it’s straightforward and irrefutable.
Sometimes it’s murky. Sometimes we’re
right and wrong at the same time -- and sometimes
we hit the practical limits of our curiosity
and shouldn’t really bother getting any
more granular than that. Like Neil says, at
a certain point it’s time to move on -- until
we decide we need to go back.
In 1972, W. V. Quine, who I referenced in
the “What is a Paradox?” video, wrote
an essay specifically dedicated to the limits
of knowledge. He opens it by asking, “Are
there things that man can never know?”
And Roger Shattuck, a writer and literary
professor, explored the consequences of understanding
24 years later in his book “Forbidden Knowledge,”
including starting off the entire thing with
a seminal question to the human experience:
“Are there things we should not know?”
And what about Gettier, who inspired a revolution
in how we think about thought? Philosopher
John L. Pollock concluded that Gettier “single-handedly
changed the course of epistemology.” He’s
92 years old now. He never published another
thing after that paper. Not a word. When asked
why, all he said was, “I have nothing more
to say.” Apparently he also invented the
mic drop.
It’s been another 24 years since Shattuck’s
book. And my answer to all the questions asked
by Shattuck, Quine, Gettier, and Plato is:
I don’t know.
And yeah, social media is nuts, but the other
day I was reading a thread by Simon DeDeo
-- he’s a professor at Carnegie Mellon and
runs the Laboratory for Social Minds at The
Santa Fe Institute. He was talking about knowledge
and justified true belief, and he said one
reason he likes doing science with others
is because they can help him disprove something
he believes more efficiently than he can himself.
He said that works best “because we need
help in exploring the unknown. If you're walking
in the woods, you can either walk towards
a landmark, or away. Walking *away*, for some
reason, seems to work better.”
That’s what we’re doing, all the time.
We’re identifying the known and exploring
the unknown. We struggle with imperfect knowledge.
And whether it’s science, philosophy, cats
or hot dogs, to get to where we’re going,
sometimes we just need to walk away.
And as always, thanks for watching.
So, Sheriff Cat. Do you arrest like humans
or do you arrest other cats? Do you arrest
dogs? Like, how does this work.. H..Hold on.
Hello?
Hey! You can watch more of Neil and I discussing
the boundaries of knowledge and science over
on StarTalk. Make sure you subscribe to StarTalk
while you’re there. It is wonderful.
Also, the summer Curiosity Box has dropped
and you can start thinking now by getting
yours at CuriosityBox.com. It’s made by
Vsauce and this is the subscription for THINKERS.
So, basically, YOU.
Bye.
