Is everything predictable? Or is there such thing as chance.

[sunoco]

What if you were to conduct an ABSOLUTELY identical experiment inside a vacuum, say... flipping a coin. With everything exactly the same... would there be any difference in the results of the two experiments? This question has een bugging me for years.

[psynapse]

Do you flip it starting with the same side up and with the same upward velocity and the same angular velocity as well as catching it in the same place then yes you will get the same results. Reminds me of chaos theory.

[sunoco]

Yes, each experiment will be conducted ABSOLUTELY the same, would there be any difference at all? Is there an element of randomness in the world? Is there such thing as chance?

[Phi for All]

You'd have to have something inhuman to do the flipping. Humans can't regulate the muscles in the hand to the degree required to flip a coin *exactly* the same way each time, especially over a period long enough for accurate sampling.

 

This is your element of chance in a vacuum. Slight differences in the way you flip the coin will provide differences between the two tests.

[sunoco]

Thats what I mean. Use a machine. Lets say there is such a thing as pure chance. Everything in the universe has an element of randomness to it. If you flipped a coin in the exact same way twice there would be tiny diferences in the results. If there was such thing as chance it would also be possible to do the exact same experiment 10 times, 9 times it would be exactly the same, 1 time it would vairy. I am not making any sense. It is hard for me to articulate what I am thinking. Maybe this will make some sense:

 

Everythig in the universe is partly governed by chance, the farther the deviation is from the norm, the less likely it is to happen.

 

 

I am sure a scientist has come up with something like this.

[timo]

Colliding two electrons at high energies will, according to current theory, give different measurements in the detector.

Whether this is because the initial conditions were not exactly the same or if completely equal intial conditions can really lead to different measurements is not known and, due to practical restrictions that you cannot prepare intial states arbitrarily exact, imho cannot be finally decided.

[sunoco]

That was what I was wanting to know. That there is evidense of chance and randomness. Two equal experiments with slightly different results.

[psynapse]

All this sounds like chaos theory, that tiny imperfections will slowly mount up until you get different results. Your machine might heat up a little and the metal might expand, for example. There is always going to be that element of "randomness" due to our inability to replicate perfection as it exists in ones mind.

[YT2095]

how far does Pi go back in digits before the decimal point?

[swansont]

If you shoot a particle at a double slit, you cannot predict exactly where it will go. There will be a distribution of possibilities.

 

You can take identical unstable nuclei. You cannot predict which one will decay first.

 

There are other examples in quantum mechanics.

[Comandante]

the same question i've been asking myself, only i've been using a dice , the dice seems to be rather popular.

 

have a box in space, vacuum inside, have a magnetic field or something else technologically advanced enough to hold the dice in exactly the same spot twice, drop it against gravity to the bottom of the vacuumed box and you get the same number twice? perhaps the probability of getting the same number twice would be 99.9999999998 or something due to the effects the dice would have on the box the first time you threw it, but you would still get the same number? how would you know that the probability wasn't 100%? you'd have to repeat the experiment until you get it wrong, but the more times you repeat it the less of a same box you will have, so basically it's not the same box anymore as it was 50 tries ago....

 

but think of this, if you had 1 million boxes that were exactly the same and the dices were in exactly the same positions and dropped against exactly the same force of gravity you could eliminate the problem of having to think about which particle moved as the gravity-powered dice hit it. you then inspect 1 million boxes and you find they all produced exactly the same number, how would you still know that the probability is 100%? that's the part i don't get, how can you ever be sure the probability is 100% when there's infinite number of times you can repeat the experiment?

[the tree]

In virtually identical systems, something as relatively huge as a die or a coin is not going to be significantly affected by quantum indeterminacy. (Well it could be, but that it ludicrously unlikely)

 

Swansont gave the only really good examples of how you can observe "chance" playing a part.

[ecoli]

reminds me of Asimov's foundation somewhat. As your test group becomes larger, the behavior is more predictable. We may not be able to predict the movement of an electron, but larger bodies tend to follow newton's laws, and we seem to know what happens when 'mob mentality' takes over.

[sunoco]

Thats the thing, I belive that not everything can be pedited. Some things are random, even the tinyest, tinyest things. Just my opinion. Maybe someday they will test it and see.

[Comandante]

I'm not a big fan of Einstein but I'll have to go with him on this one - in my belief God did not play dice, even the movement of electron can be predicted as I don't see how there could be such thing as random or ‘probability’. The thing that swansont mentioned about distribution of probabilities I see as nothing more but a sad fact that we formulated a law that only partly describes the movement of electrons - and that's probably because we can't account for the rest of the factors affecting it. Entanglement might hold the answer.

 

If we knew everything there was to know about the universe then we would theoretically be able to predict everything that was about to happen. The only problem is that we probably wouldn't have sufficient computing power to do so as the number of factors would be huge with a capital H. I am also not a big fan of the uncertainty principle - my 6th sense is saying that it's not quite right

 

I like to think that not everything is predictable for that would mean that we can make a choice, but the logic is somehow dragging me away from it and it more and more seems that there really is what some call destiny, but then again this leads me into Matrix philosophy and I’m tired from that.

[fredrik]

> Is everything predictable?

 

I'd say unless I missed something big - "apparently not"

 

Could everything "in principle" be preditcable given X?

 

What does "in principle" mean, and what is X? That we are complete like some kind of God?

 

Let's just suppose for fun, that God does NOT place dice. How does that imply that *We* do not have to place dice? God may be complete, but we are hardly not? It's still two different things to me.

 

The question, could I predict everything "if I was God" is not really a clear question. The answer could be anything you choose, depending on how you define it.

 

Not really the same, but IMO "related"...Gödel's incompleteness theorems

http://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorem

 

/Fredrik

[swansont]

I'm not a big fan of Einstein but I'll have to go with him on this one - in my belief God did not play dice, even the movement of electron can be predicted as I don't see how there could be such thing as random or ‘probability’. The thing that swansont mentioned about distribution of probabilities I see as nothing more but a sad fact that we formulated a law that only partly describes the movement of electrons - and that's probably because we can't account for the rest of the factors affecting it. Entanglement might hold the answer.

 

 

You're grasping at quantum straws here. If you read up on the phenomena at hand, and look at the experiments done, especially the local hidden variable/EPR experiments, you will find things that contradict your pronouncement.

 

"God does not play dice" is not a scientific pronouncement, and its use as one is the argument from authority fallacy in full glory. Science comes from the observation of how nature works, not from our opinion of how it should work. Quantum theory is quite successful at predicting and explaining relevant phenomena, and the uncertainty and probabilistic nature are inherent to that. Belief and opinion are irrelevant; show me some data. Predict where that next photon or electron will go, or when a nucleus will decay, and you have something.

[Comandante]

You're grasping at quantum straws here. If you read up on the phenomena at hand, and look at the experiments done, especially the local hidden variable/EPR experiments, you will find things that contradict your pronouncement.

 

That is very likely indeed. But can you explain to me this; Say at the moment we are only able to produce distribution of possibilities as you call it for the possible paths an electron can take. Is it true that if you're coming up with 'probability' (each possibility has its own probability?) for something to occur there are things/factors you can't account for which can affect the outcome of your experiment? In other words if you are unsure of which path the electron will take how could you be certain that it can never be known? Isn't that like having a reaction without an action?

[swansont]

That is very likely indeed. But can you explain to me this; Say at the moment we are only able to produce distribution of possibilities as you call it for the possible paths an electron can take. Is it true that if you're coming up with 'probability' (each possibility has its own probability?) for something to occur there are things/factors you can't account for which can affect the outcome of your experiment? In other words if you are unsure of which path the electron will take how could you be certain that it can never be known? Isn't that like having a reaction without an action?

 

It's because the data indicates that the electron (or photon, or atom or molecule) actually goes through both slits. IOW, it doesn't have "a path" unless you actively restrict it to having only one option.

 

Like I said, you have to read up on this. It's not philosophy or belief or opinion. It's all backed up by experiment, even though some of it is counterintuitive.

[Comandante]

It's because the data indicates that the electron (or photon, or atom or molecule) actually goes through both slits.

 

I've heard of that somewhere, once upon a time... I might check it out as you said, but not soon, quantum physics isn't my first preference