Can one predict the
evolution of a system
etc., etc., etc....
Sometimes, everything goes wrong
You predicted a normal college day
Then your alarm clock didn't ring
Running late, you couldn't find your backpack
(or car keys, smartphone, etc.)
You finally stagger out the door,
but your car wouldn't start
That's why you miss a surprise quiz
Basically, the future was unpredictable
It's like that for the entire forecasting field...
1. Spoil Sport of Prediction #1: the Observer Effect
To figure out what happens next,
you need to know where things are now.
Observing changes what is observed
You hit a billiard ball
What happens next?
What do you need to know to figure it out?
You need to know
the current state of the pool table
the speed and direction of the ball
The observer effect
The principle that:
The act of finding out
"where things are now"
the current state
of the system of interest)
changes it to something else
(i.e. perturbs the system).
the observer effect
is most noticeable for:
very small things, or
the observer effect
applies to any scenario:
solar sails use that
called radiation pressure
affect the electricity
changes the person
"Measurement always changes the thing measured"
Can you think of some examples?
What about BIG things?
Measurement thus can be inaccurate!
The observer effect on the web
Dr. Quantum (5:40)
https://www.youtube.com/watch?v=2mIk3wBJDgE is similar)
The observer effect is even popular in new age-y circles
It is even a Star Trek episode:
(30-sec. trailer) http://www.youtube.com/watch?v=9eqb9PDILMU
And not just physics...
Social science also has an observer effect
See first few seconds of:
So. . .
. . . Can you think of
of the observer effect?
(You could write it down, or groups could jointly try to think of examples)
Does the observer effect
of things like
the next presidential election
your project topics
Here are a few more
. . . if you are watching over kids, they act different
. . . What about adults?
. . . Ever try to look at
the back of your head
using two mirrors?
It makes you move your head around
. . . What about fans watching a game?
. . . What about measuring the weather
for weather forecasting?
. . . What about measures of
printed in news articles?
Suppose you could control the observer effect
(Is this even possible?)
. . . now just figure out the 6-D position-&-velocity of every particle (etc.) in the universe
. . . . . . then crunch with a giant computer to tell the future! Right?
. . . Unfortunately, no.
. . . . . .This just brings us to:
2. Spoil Sport of Prediction #2:
The Heisenberg Uncertainty Principle
("What is the Heisenberg Uncertainty Principle?"
4:43, 1,548,081 views)
it applies to all particles
not just electrons
Here it is with
photons (light particles):
. . . You could do it with
a laser pointer and
a piece of black plastic cut from a notebook cover!
The Uncertainty Principle:
It says you:
cannot precisely know
position and momentum
at the same time
The best achievable
uncertainty in position,
times uncertainty in momentum,
h is Planck's constant
So h/4*pi is a constant too
What happens if we have
total accuracy for position, x
in other words, ∆x=0 ?
Since momentum m
velocity v times mass:
then v or mass has great uncertainty:
you don't know the velocity
you don't know the mass
What is momentum in everyday terms?
. . . Suppose you are on skates
. . . Something with momentum flies toward you
. . . You catch it
. . . The more momentum it had,
the faster you slide backward
. . . . . . Don't like that it's not just you,
. . . . . . it's you and the object?
. . . . . . . . . then toss it back just enough so it has v=0
. . . It's momentum m transfers to you
. . . . . .the more momentum it had,
. . . . . .the more you have now
. . . . . .the faster you slide backward
. . . Momentum is different from kinetic energy
What is the
that is, ∆m,
and mass=5 lb.?
Typically we are
relatively sure about mass,
so ∆m shows up as ∆v not ∆mass
So there is typically uncertainty about
position ∆x, and velocity ∆v
of any object
So let's focus on
Does the uncertainty principle apply to bowling balls? Asteroids?
Let's break ∆m
(uncertainty about momentum)
into its components:
Assume mass is known & constant (say 10 lb.)
If mass is high (bowling ball)
∆x*∆v is: small or large?
...permitting ∆x and ∆v to be small
If mass is small (subatomic particle)
is: small or large?
...permitting ∆x and/or ∆v to be much bigger
Some more details
To fully describe a system
such as the universe
some small part of the universe
we need simply list
the position and velocity (and mass)
of every particle in it.
How many numbers are needed
to describe the position?
a side-to-side location
a front-to-back location, and
(also known as
x, y, and z coordinates)
How many numbers are needed
to describe the velocity,
where velocity consists of
a speed and a direction?
a side-to-side speed
a forward/backward speed, and
an up-down speed.
Plus the mass,
gives 7 numbers
This concept is
easiest to visualize in
a 2-D simplified example:
So we need
for every object
to fully describe the system
since each object has a mass as well).
Now for the bad news...
those 6 or 7 numbers are
impossible to get with full accuracy,
they include values for both
position and velocity (and mass, #7)
The Uncertainty Principle tells us that
for one results in
for the other.
if the Observer Effect
our prediction ambitions,
the Uncertainty Principle will.
But what if we could control both?
Well we can't!
But just suppose we could
(maybe we could do it "enough")
we're not out of the woods,
because of the
esoteric physics phenomenon called
3. Spoil Sport of Prediction #3:
According to quantum theory:
objects are not as
localized in space
as we intuitively think.
Instead, objects have
and are actually
"smeared" over a space
within which they exist
with some probability
at each point
in that space.
This leads to weirdnesses like:
A tiny object
such as a
if very near a thin barrier,
has a certain probability
of being on the other side!
It may be observed there,
and if so,
it has thus "tunneled"
through the barrier
without making a hole in it.
This is quantum tunneling.
Quantum tunneling also applies to
the ability of objects to "tunnel"
through other kinds of barriers than solid ones.
For example, consider a notorious example:
an idealized pencil balanced on its tip.
If the tip is sharp, except for a tiny flat spot
(say, a couple of atom wide)
it might be difficult to balance,
but should be possible
with sufficient care.
Well not exactly.
Because the pencil is actually "smeared" a little bit,
it has a certain, rather small probability
of being tipped enough to lose balance and fall.
Since the smearing is symmetric,
it could in fact fall in any direction.
The probability of being tipped enough
to lose balance is small and a single such pencil
would be unlikely to fall for a long time
(Easton, 2007, p. 1103,
But get enough pencils together
and one will fall soon enough.
balance an array of 1000 x 1000 pencils
and one will fall,
knocking over other pencils
and leading to a general domino-like conflagration
with an average (but unpredictable) delay of
about a month.
What pencil will start the general crash
and in what direction the pencils fall is
impossible to predict.
Thus, quantum tunneling
prevents accurate prediction
and is a
spoil sport of prediction.
But maybe the system we're interested in
predicting the future of
is not so finely tuned.
Maybe we can handle
the Observer Effect,
the Uncertainty Principle,
and quantum tunneling
adequately for our system.
Alas, our troubles are still not over!
Spoil Sport of Prediction #4:
The Butterfly Effect
a butterfly flapping its wings
will create a small atmospheric disturbance.
That disturbance will propagate unpredictably.
Some time later (how long?),
the paths of hurricanes will be determined by those tiny flaps!
There is a movie The Butterfly Effect
Highly rated by viewers
Less so by professional critics
One mathematical description
of atmospheric cycles
whose future behavior depends seemingly unpredictably
on small present events,
may be modeled by a special kind of water wheel.
fire wheel: https://www.youtube.com/watch?v=MszbeTgpcDg
“When our results concerning
the instability of nonperiodic flow
are applied to the atmosphere,
which is ostensibly nonperiodic,
they indicate that
prediction of the sufficiently distant future
is impossible by any method,
unless the present conditions are known exactly.
In view of the
inevitable inaccuracy and incompleteness
of weather observations,
precise very-long-range forecasting
would seem to be non-existent.” [emphasis added]
— Edward N. Lorenz
Let's discuss what "butterflies" might affect our term project topics!
What about the observer effect,
the Heisenberg uncertainty principle, and
controlled the Butterfly Effect
and all those others?
Then welcome to...
5. Spoil Sport of Prediction #5:
To figure out what happens next,
you need to know where things are now.
But you also need to know
what outside influences
will impinge on the system between "now" and "next,"
whenever "next" is.
Consider pool again
Say you know
Every location of every ball
The velocity of each
A fast computer can
Figure out what will happen
Several seconds into the future
Faster than it really happens!
After that, various issues cause problems
(Spoil sports 1-4)
Suppose we tame them somehow (a big if)
Our problems are not over:
a draft hits the table?
The table is very slightly tilted
Someone bumps it?
the evolution of
that's why they're called
A Lorenz water wheel,
but it's raining
Every raindrop is a butterfly flap
...whose tiny actions
change the direction of the wheel
at some future time.
to a system
is like a
butterfly wing flap
- how about the future of
a person's illness?
How can we avoid
total loss of control of
society, systems, selves...?
Computer round-off error
another source of perturbations
from outside the system under study
Frictionless pool table simulation that repeats
The butterfly effect was discovered as an effect of round-off error
(recall youtube simulations)
Let's identify some
likely to affect
the future of
some of your favorite topics
(we could list them on the board)
6. Spoil Sport of Prediction #6:
- Why Care
(About the Future)?
a feeling of
dread, anxiety or anguish
the "big questions"
Does the kind of existence affect the answer?
. . . Difficult struggle for existence
. . . Prosperity
"Eat dessert first" - Hitchhiker's Guide to the Galaxy
we shall die"
- Isaiah 22:13, etc.
"Don't Worry, Be Happy"
- Bobby McFerrin (after Meher Baba)
Decisions often focus on the short term
. . . Business decisions focus on short term
. . . Political decisions focus on short term
. . . Many people focus on the short term
. . . What about animals?
. . . What about plants?
. . . Why is it good to focus on the short term?
. . . Why is it not good to focus on the short term?
. . . Why is it good to focus on the long term?
. . . Why is it not good to focus on the long term?
What does short term focus say about existentialist angst?
What does long term focus say about it?
A school of philosophy
Søren Kierkegaard (1813-1855)
was a key figure in its development
. . . Danish philosopher and theologian
"...focused on subjective human experience
rather than the objective truths
of mathematics and science..."
"...interested in people's quiet struggle
with the apparent meaninglessness of life..."
- Wikipedia, http://en.wikipedia.org/wiki/Existentialism
What do you think of that?
Discussing the future of humanity is nice,
but what about my (your) future!??
. . . If life is meaningless,
then does the future matter?
. . . Is life meaningless?
. . . Is the question meaningless?
. . . Is it important to give life meaning?
. . . What should one try to do with life?
. . . Maybe reasoning from accepted
first principles does not resolve these
Therefore you can choose the answers you prefer!
(Or not choose, it's up to you)
Equivalently, you can choose
to add first principles
as needed to get the answers
How about maximizing the integral
of positive feeling in the universe?
. . . . . . You could pick pessimistic answers,
you could pick optimistic ones too
. . . . . . Pure logic won't say which is right
. . . . . . Better to pick the optimistic ones!
Because life's more fun that way
. . . That seems like common sense...
Yet it is not always a matter of conscious choice
Optimistic and pessimistic moods
Taken to extremes - bipolar illness
That's brain chemistry not choice
Yet... optimism can be taught & practiced
Why societies can collapse
(Another kind of existential problem)
You might think that societies would try to
anticipate and control existential risks
But sometimes they don't
What existential risks are possible for us?
Here is a taxonomy(Source: J. Diamond, Collapse: How Societies Choose to Fail or Succeed)
Example: foxes and rabbits in Australia
Anasazi civilization (Arizona) did not anticipate local climate change (drought)
France built the Maginot line for defense, but lost WWII in mere weeks
Etc. (can you think of any)
Failure to recognize the problem when it is happening
Examples: any slow-moving trend obscured by short-term effects
Note the noise-and-signal issue
Also called "creeping normalcy"
Try an images.google.com search on:
average global temperature by year
Etc. (Can you think of any examples?)
Failure to try to solve the problem after it is recognized
Why on Earth would anyone or any group do that??
Yet according to Diamond this "failure is the most frequent"!
. . . Failure may benefit influential special interests that therefore push it
. . . Greenland Norse leaders kept cows (unsuited to the cold)
. . . The few pike fishermen stocked pike in Montana waters,
destroying trout for the many more trout fishermen (p. 427)
. . . "Throughout recorded history,
actions or inactions by self-absorbed
kings, chiefs, and politicians
have been a regular cause of societal collapses" - p. 431
. . . Any examples closer to home of
benefiting a few at the expense of the rest?
. . . Is this rational behavior?
. . . Unregulated access to common resources
. . . . . . "If I don't take as much as I can, someone else will"
. . . . . . Pretty soon it's gone!
. . . . . . Any examples?
. . . . . . Is this rational behavior?
. . . . . . Solutions?
Trying but failing to solve the problem
Greenland Norse colony: "The cruel reality is that...Greenland's cold climate and...limited...resources have posed an insuperably difficult challenge to...a long-lasting sustainable economy." - p. 436
So should societies think differently?
7. Spoil sport of prediction #7: The care horizon
Time value of money
How much is the future human race worth?
We'll increase it later, but...
let's start with a bargain basement $100.
If you had $98.04 now, and
put it in the bank at an interest rate of 2% per year,
then in a year you'd have $100
So: getting $100 one year from now is only worth having $98.04 now
(from a "Time Value of Money" perspective)
getting $100 in 2 years is only worth $96.12 now
because adding 2% to $96.12 gives $98.04 in one year, and compounding by adding another 2% gives $100 a year later.
Extending this reasoning further:
the human race in a modest 233 years
would be worth . . .
just under a dollar now
In 466 years? Less than a penny.
$100 is way too small!
It's fair to say that a hundred dollars is an underestimate for the value of the entire human race. So let's increase it to a fair (or at least fairer) price. We might multiply the number of people by the value of the life of each and every person on the planet.
What is the value of a person's life? Economics (known as the dismal science, even to economists) tells us that the de facto value society places on a human life can actually be calculated, and courts of law in fact sometimes do such calculations.
Answers vary, of course, but a few million dollars is often within range.
Multiply that by the number of people in the world and you get a biggish number:
$100 quadrillion for the value of the human race (at most).
Is $100 quadrillion way too small?
But wait - maybe you don't trust the financial and legal wizards with something so important. After all, we already trust them with some pretty important things, and they periodically betray that, seriously screwing things up. Maybe we should use a higher number, just to be more sure we aren't under-valuing ourselves.
How about a dollar for every single atom in the known universe? That's around $10^80 (1 followed by 80 zeroes dollars)? It is a lot of cash. Way (way way) more than the United States has ever printed. There are literally not enough atoms in the known universe to even print that much money. Yet, if that is the value of humanity's existence 9,070 years from now, the value at present would be...$100! A scant 466 years after that? Less than a penny. How about the present value of humanity existing in a million years? The answer is a fraction of a penny so tiny that popular spreadsheets, calculators and computer programming languages can't even state it. They typically just think it is 0, but if you must know, it's actually about $0.000
It's STILL too small!
Wait - someone in the back has a question - yes? "But it's not just the value in year one million we're after. We also need to add in the value in year 1,000,001, year 1,000,002, etc., forever and ever. That's got to add up, eventually." Well, only a little, it turns out. The value now is "bigger," but still less than $0.000
Making it personal: It's not a money thing at all
Maybe you are still unconvinced.
Such sophistry fails to capture the real facts at a gut,
common sense level, you might say.
Then consider the following argument.
You care about yourself, so you don't want humanity to end while you are still alive (it might not be pleasant). You care about your children (or you will if you have any some day, or maybe you care about some or even all other children). So you don't want humanity to end during their lifetimes, even if you are already gone. You probably even care (or will care) about your grandchildren because you will hopefully get to know them personally. Furthermore, you care about their grandchildren (though probably less) simply because you care about your grandchildren, who care about theirs. But you have no gut level reason to care about the generations after that, because neither you, nor anyone you care about will ever know them. To put it another way, how much do you care about your grandparents' grandparents, and how much did they care about you?
Maybe you and your great grandchildren will live long enough that you'll care about your great grandchildren and theirs, instead of just grandchildren. Yet that is still only 6 generations into the future, not even the biblical 7, a couple of centuries or so at the most. So relax, quit worrying, eat dessert first.... In particular, don't bother with predicting past the 2-century "care horizon," because there's little point to it.
The 2-century care horizon is, thus, our last spoil sport of the prediction game.
D. Easton, The quantum mechanical tipping pencil - a caution for physics teachers, European Journal of Physics, vol. 28 (2007), pp. 1097-1104.
R. Posner, Catastrophe: Risk and Response, Oxford University Press, 2004
"Time Value of Money": TVM is standard terminology in the finance and accounting world.
"Well, only a little, it turns out." There is a formula for calculating the sum of a geometrically decreasing, infinite series. Look it up (or play with a spreadsheet instead).