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Hey, Vsauce. Michael here and Derek.
78? That's so random. Or is it?
What does it mean to be random?
Can anything really be random? What's the most random thing ever?
Today let's stop being random and become 'ransmart'.
If something is unpredictable,
and contains no recognisable patterns, we call it random.
So let's begin our hunt for the most random thing with a coin toss.
The Australian 50 cent coin is one of the largest coins
currently in circulation.
Coin flips and rolling dice are not intrinsically random,
they are only random because of our
ignorance. If we could know every initial condition
the exact forces and properties that play for a particular flip or roll,
we could theoretically calculate the result before it
even happened. And, sure enough, researchers have built coin flipping robots
that can precisely control a flip to get the result they want
100 percent of the time.
So here is our question. Is there anything you couldn't predict
even if you knew everything? A process determined
by nothing? And how can you be sure they're
aren't any patterns in what you're looking at? Maybe you just haven't looked
for the right pattern yet.
Or maybe you have already seen true randomness
but didn't know it because you didn't look for long enough.
As if protected by a sort of camouflage,
a random process can, and will, occasionally produce patterns.
YouTube URLs are pretty much
random. A unique one is made for every uploaded video, but sometimes,
like the proverbial monkeys typing away on typewriters,
YouTube generates a URL that contains, by chance, a word.
The official music video for 50 Cent's
'In Da Club' contains a synonym for bottom.
This video was assigned 'hello',
there are some 'sexies' and a sauce. If you want to find out if a particular word
has been randomly assigned to a video yet, you can search for it
by using this string in Google.
The point is, randomness is difficult to identify. It is easier to be certain that something
is not random than that it is. But despite this elusiveness something interesting
is going on right now. Increasingly, we,
especially young people, are calling clearly predictable
things random.
Like randomly running into your best friend at a popular restaurant.
Or hilariously bizarre combinations of things that we call
totally random because they are seemingly unrelated,
even though, of course, they were chosen not in random but in a very determined way
because they are all unrelated.
Those guys that showed up at the party last night you didn't know,
they weren't randos in a mathematical sense.
They knew about the party, we're in the mood to go to a party and we're in the area.
Pretty predictable, actually.
This non-statistical use of the word random annoys
some people but it's not that far off from the original meaning
of the word. In the 1300s, random
meant running or at great speed.
Later, it would be used to describe things that have no definite purpose.
It wasn't until the 1800s that random took on a particular mathematical definition.
Then in the 1970s, MIT's student paper
popularised the use of the word random to simply mean strange.
Of course, just because something is strange doesn't mean it has
no discoverable cause. Why have we started calling so many predictable things
random? Well, many theories revolve around
the amount up information and new people we are confronted with
at an increasing rate; now more than ever before.
Perhaps it's just easier, almost a bit of a relief
to call things random, so that we can move on
to synthesise other information.
Take a look at this die.
Now, as you can see, it rolls a five most of the time
but not all the time. Over time
a sequence of its results will contain less randomness.
But it is still random. Any face is possible and I have no guarantee beforehand
of knowing which face will show up. The outcomes I'm selecting from make the
resulting sequence less full of
randomness but the process is still random.
Even though a die and a coin are extremely sensitive to their initial conditions,
and, over the course of normal use, are quite
unpredictable, they do over time
exhibit certain biases. Biases that make them
a bit more predictable and a little less random
than you might think. First of all, dice. Even precision dice are only quality
controlled within a few micrometers.
You can check this out yourself. Make
two stacks of ten or more similar dice.
Now, if you orient each die every which way, you should pretty much get two equally sized stacks
But, if you arrange each stack
along a shared axis, so that every die faces the same way,
any regular imperfections caused by the manufacturing process may become visible.
But what about coins?
Well, some fantastic research has been done on what happens when they spin
and flip. For instance, it has been found that US nickel is just the right diameter and
thickness to wind up landing
not heads up or tails up when flipped, but on its
side, about once every six thousand times it's flipped.
But what about the fairness of flipping a coin? Well, if you flip a coin like
this, for statistical and physical reasons the side facing up
before the flip begins, doesn't actually have a fifty percent chance of being the result.
Instead, as researchers at Stanford have found, it actually has
a fifty one percent chance. In this case it was the other side though.
Still pretty random.
If you want a coin flip to be as fair as possible,
you should just catch it in your hand. Don't allow it to hit the ground, bounce, tumble
and spin. That's because researchers have found that when a coin spins
larger biases come into play. The shape of its edge,
its centre of gravity. The heavier side tends to go down
quite often. In the case of some coins as often as
eighty percent of the time. It's been found that a one euro coin
will spin, and land heads up, more often than not,
and a US penny will land tails up
more often than not when spun. But like I said
earlier, theoretically if we knew everything about the initial conditions
of a coin flip or a die roll, we could
calculate beforehand their outcome.
Why don't we do that more often?
Well, it's extremely difficult.
Insane amounts of precision would be required because the smallest
difference between two initial conditions can be magnified over time
leading to chaotic, extremely difficult to predict, results., the service Derek and I used
at the beginning of this video to generate a random number, uses
atmospheric noise. It's extremely hard to predict,
but technically still a deterministic system.
All that noise came from somewhere and if we could just find out those initial
conditions we could,
theoretically, predict their outcomes.
If we want a system more random
than that we will need to find one that is determined by nothing
and for that let's look closer. Quantumly close.
Quantum mechanics may have our answer.
It describes the properties of quantumly sized things
as probabilities;
just chances. Not because we don't know enough yet to be certain,
or predict, but because, well, the idea is
there's nothing there to predict.
There is no beforehand we could know.
Whether or not a particular individual radioactive atom will decay or not,
or whatever the spin of an electron is,
is only knowable once we look. They're determined by a deep-seated
randomness woven into the universe itself.
Einstein couldn't believe this. He refused to accept, as he said,
that "God played dice with the universe."
But... experiments
with entangled particles have shown
violations of Bell inequalities.
Entangled particles are particles that exhibit similar properties
even when separated by large distances.
Now, if they agreed on those shared properties to have, or are somehow
determined beforehand to have them, their behaviors
should satisfy Bell's famous inequalities. But experiments have found
that instead the likelihood of what a machine will see when measuring one particle
determines how the other machine will measure the other particle.
It is here, when we look that the chance is determined. Explanations for this
are even weirder but what the results suggest is that
the chance of seeing particular quantum qualities
don't pre-exist.
They happen when you look.
So, if you are ever feeling boring or
predictable, just remember that you are made out of octillions
of quantum probabilities. Dice that don't tumble in any
analysable way we could ever predict.
They are the most random thing.
God may play dice with the universe, but they are
the best dice in the universe.
And as always,
thanks for watching.
But what does it all mean?
Well, true randomness doesn't mean anything. I mean, for us to have meaning we need
structure, predictability and that is what I'm exploring over on my channel, Veritasium.
Wow, okay. So
let's go over there and take a look at what is
not random. Veritasium, let's go.
I'll see you guys over there. It's going to be awesome, come with us.
And as always,
thanks for watching.