Chance
&
Uncertainty

Now we know that humans don't always need to know measurements exactly,

it's useful to be able to think in terms of 'more or less'.

Estimation is how they make a guess that they don't expect to be exact.

But calculating chance is different

because even though any one or more of a number of different things can happen,

the chances of them happening can be calculated exactly.

If you roll a dice with six faces,

the chance that you get any particular number is one in six,

or if you toss a coin with two faces,

just head or tail,

the chance that it will land one way or the other are one in two.

And it's always that way,

even when it seems crazy that it can be.

Toss a coin and get heads five times in a row,

and which face is most likely to turn up next time?

Well, it seems obvious that it should be tails,

and the question makes you think that one should be more likely than the other,

but it's still one in two.

That's the maths of it,

and that doesn't change.

But because numbers are exact,

they are not so good for giving approximate chances,

for that people prefer to use words,

whether something is more or less likely,

more or less probable.

Maths doesn't like to be vague,

it needs to be exact,

as on a scale between zero and one,

with zero being no chance,

and one being absolutely certain.

But even though decimal numbers can be very exact,

people will often find it easier to calculate using fractions,

like one third, or one in three,

or people will use simple percentages,

like twenty five percent for one in four,

or fifty-fifty for one in two.

Of course, sometimes

People can be very interested in calculating chances.

Because if chance can be calculated for certain,

that can give you an advantage,

and people can use that in business,

but also in competitive games,

and there the calculations can be very complicated,

when there's more than one way to get a result.

In a pack of 52 playing cards, what are the chances of drawing an ace?

And what are the chances of drawing a seven?

And don't let the question trick you.

If you roll two dice,

what is the chance that you will throw a seven,

and is it the same for throwing a nine?

And calculating chance gets even more tricky

for games like backgammon, or chess,

where the pieces move in different ways,

or the game of Go,

with so many different places to move to.

So people use games to play with numbers and chance,

and those skills can be useful in the rest of their lives.

But even board games have rules to keep things simple.

Sometimes it can seem like there are so many things involved

it is impossible to calculate,

but still it may be possible to see when and how often things happen over time,

and calculate a probability with those numbers.

But sometimes,

as with the weather

humans just have to be satisfied with the best they can get,

because they will never be able to include

what is called the butterfly effect,

where a tiny change can cause a big difference

in an end result a long way away.

Indeed, God's creation is so vast and complex

that humans will never be able to number it.