("Doctor Who Closing Credits" by Murray Gold)
- Allons y.
We as humans have always been fascinated
by mind twisters, like riddles and puzzles,
but nothing intrigues the human mind more than a paradox.
A paradox is a statement or situation
that completely defies logic,
which is why so many of us are perplexed by them,
because our brains hear them and it's like,
"I don't know what to do with this information."
Because I felt like making you guys think
just a little bit this week,
I gathered the most interesting ones to share with you guys,
so here they are: the ten most mind-twisting paradoxes
of all time.
Number one is the Ship of Thesus Paradox.
This paradox is also known as the grandather's axe paradox.
Suppose you have a ship made of 100 pieces of wood.
Every now and then you replace an old piece of wood
with a new piece and you keep the old pieces in a shed.
Over the course of many years,
you replace all of the old pieces with new pieces of wood,
but that's still the same original ship to you, right?
Well, the paradox occurs when you consider
what happens when you take all of the old pieces of wood
and reassemble them.
The question then becomes: Which is the original ship
and also why are you building ships in the year 2014, man?
What are you, Noah?
Number two is the Omnipotence Paradox.
This paradox asks: Could an omnipotent being
limit its own power?
Another way to word it is: Could God create a stone so heavy
that even he couldn't lift it?
Now, this is paradoxal,
because if God does have unlimited power
and can do anything, then sure,
of course he could create a stone that he couldn't lift.
If that's true and he couldn't lift it,
then that's something he can't do,
hence the paradox.
This is actually one of the most well-known paradoxes
in history and has been around since the days
of ancient Greece.
Number three is the Monty Hall Paradox.
This paradox is loosely based off the old TV game show
Let's Make a Deal.
Suppose you're on a TV game show
and there's three doors.
Behind one door is a car,
behind the other two doors are goats.
Now, suppose you pick a door,
say door number one,
and the host, who knows what's behind each door,
opens door number three, which has a goat behind it
and asks you if you want to switch to door number two.
Now, at this point, you might be thinking,
Well, it doesn't matter, because they all have
a one in three chance,
but therein lies the paradox.
Believe it or not, it's actually advantageous
for you to switch to door number two,
because it mathematically has a two in three chance
of having a car behind it,
which is completely counterintuitive.
Now, if you're wondering how that works,
I don't have the time to mathematically explain it
in this video, but just trust me.
That's how it is.
I think the real question here is what happens
when the contestents pick the wrong door.
Do they get to keep the goat?
Because, I mean, that's not so bad.
You get unlimited milk, a warm hoof
to hold you on cold nights.
It's magical.
Number four is the Unexpected Hanging Paradox.
A judge tells a prisoner that he's sentenced
to be hanged at noon one week day in the coming week,
but that it'll be a surprise and he won't know
until he executioner knocks on his door
on the chosen day.
The prisoner reflects a bit on his new sentence
and concludes that since it's to be a surprise hanging
that it can't happen on Friday,
because if it hasn't happened by Thursday,
there would be only one day left,
thus it isn't a surprise.
He then continues to reason that the hanging
can't be Thursday either, because Friday's eliminated
and if it hasn't happened by Wednesday,
Thursday would not be a surprise.
He continues this line of reasoning
and concludes that the hanging cannot happen
on Wednesday, Tuesday, or Monday
and finally decides that the hanging will not happen at all.
This is, of course, until the executioner knocks
on his door on Wednesday at noon
and everything the judge said came true.
The paradoxal nature of this situation
is primarily due to the language used
and also the fact that if you don't go back
and listen to that about three times over,
you're not gonna understand it
and be confused as (beeping).
Number five is the grandfather paradox.
This is one of the most famous paradoxes ever created.
Suppose a time traveler goes back in time
before his grandfather meets his grandmother.
If the time traveler kills his grandfather
that would mean he was never born,
but if he was never born, he wouldn't be able to go back
and kill his grandfather in the first place.
Personally, I'm just really glad that this is a hypothetical
and that we can't time travel yet,
because going back and changing even the slightest thing
can have consequences that will ripple
throughout the universe.
Eugine, why do I have hair?
Your, your time machine worked, didn't it?
Yeah, I sort of stepped on an ant,
so that's why--
Huh.
Well, I guess this isn't so bad.
(laughs) Yeah, except everyone in this universe
now eats with their butts.
So, sorry.
Number six is the Barber's Paradox.
Suppose that there's a town with just one male barber.
Now, in this town, there's a rule that every man
must keep himself clean-shaven,
either by shaving himself or going to the barber
and having the barber shave him.
Using that rule, logic follows that the barber
only shaves men who do not shave themselves.
The paradox is this:
If the barber does not shave himself,
he must abide by the rule and shave himself,
but if he does that, according to the rule,
he will not shave himself.
This is a good example of what's called
an infinite regression, where the story just goes round
and round and just gets really drawn out.
Kind of like the final seasons of Lost.
Number seven is the Fletcher's Paradox.
Also known as Zeno's Arrow Paradox,
this paradox challenges what we think we know about motion.
It correctly states that in order for motion to occur,
an object must change its position.
Using an arrow in flight as an example,
if you look at any one instant in time,
in order for that arrow to be moving,
it must either be moving to where it is
or where it is not.
Now, of course the arrow cannot move to where it is,
because it's already there,
but it also cannot move to where it is not,
because in a single instant,
no time elapses for it to move there.
The conclusion is that in any one instant
no motion is occuring.
If no motion can occur in one instant,
no motion can occur in any instant,
meaning motion is impossible.
This is of course a paradox,
because we observe things in motion every single day.
Number eight is the Epimenides Paradox.
Also known as the Liar Paradox,
this is another example of an infinite regression
that can be phrased in many ways,
but most simply as follows:
"This statement is false."
Now, if the statement that I just said were in fact false,
then of course it would be true,
but if it were true, then that would make it false,
which of course would again make it true,
but then that would make it false...
and it's true...
What, what were we talking about?
Number nine is the Sorites' Paradox.
Also known as the Paradox of the Heap,
this paradox is deceptively simple.
Suppose you have a heap of sand
composed of one million individual grains.
If you remove a single grain, it's still a heap of sand.
Therefore, that argument must hold true
for any such number of grains.
Well, if you follow that logic
and continue to remove one grain of sand
at a time until there's only one grain remaining,
you're left with only one of the following two conclusions.
Either a heap can be composed of a single grain of sand
or there is no such thing as a heap.
I know (explosion).
Finally, number ten: the Raven Paradox.
Created by logician Carl Gustav Hempel,
this paradox is based off the following three statements.
Number one is all ravens are black.
Number two is everything that is not black is not a raven.
Number three is this green thing is an apple
and thus not a raven.
Now, here's what's interesting.
By saying those three sentences in that order,
it logically follows that the sight
of a green apple is somehow evidence supporting the notion
that all ravens are black.
Now, this is of course a paradox,
because it implies that information has been gained
about ravens by simply looking at an apple,
which of course makes no sense.
Or does it?
(suspenseful opera)
Anyways, that's all for this video, guys.
I hope you enjoyed it.
I just wanted to try something
a little bit different this week.
You know, make you think a little bit, baby.
These were the paradoxes that I personally thought
were most interesting, but there's a lot more out there,
like the Coastline Paradox, the Paradox of the Court,
the Unstoppable Force Paradox,
Schrodinger's cat experiment.
Weird name, I know,
but it's all very interesting.
If you're interested, I'll put the link in the description
to the Wikipedia article where I got all these from.
As always, if you wanna add me to Facebook and Twitter,
the links to those'll be in the description,
along with all my other social networking sites.
You better add me, baby,
because I learned you something today.
Other than that, I'll see you guys next Saturday
with a brand new video.
Peace.
(excited music)
Hey, you made it to the outtro screen.
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Other than that, I'm gonna go edit this bitch
so that I can enjoy my weekend.
I hope you do the same.
I'm gonna see you next week, next Saturday, yeah.
Goodbye now.