As far as I know there is no real randomness in nature, every event or action is actually influenced by previous events therfor making every action a reaction. But if one would have all the knowledge in the universe, would he be able to predict the future for 100% correct?
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Randomness
- Thread starter Leçi
- Start date
kenandkids
New Member
No.Leà§i said:As far as I know there is no real randomness in nature, every event or action is actually influenced by previous events therfor making every action a reaction. But if one would have all the knowledge in the universe, would he be able to predict the future for 100% correct?
Ok, bits of nature are not deterministic but instead fit a probability distribution. The location of a given particle, X, can only be predicted as a probability. Ie, there's a 10% chance it will be here, 11% chance here, 12% chance here etc etc, though it's not quite like that. Which of those it ends up at is random, but governed by probability.
Back to your example, even if you knew the exact state of the Universe at a given time, the best you could do for the next instant in time would be to give probabilities of likely next states, but which state it happened to be in would be random, steered by probability.
Back to your example, even if you knew the exact state of the Universe at a given time, the best you could do for the next instant in time would be to give probabilities of likely next states, but which state it happened to be in would be random, steered by probability.
kenandkids
New Member
We don't know yet.Leà§i said:But what governs this randomnes?
RigelKentaurusA
New Member
It's more than just a lack of knowledge. Consider the double-slit experiment... that interference pattern shows up even if you fire photons one by one.
http://www.youtube.com/watch?v=wEzRdZGYNvA
http://www.youtube.com/watch?v=wEzRdZGYNvA
Leà§i said:As far as I know there is no real randomness in nature, every event or action is actually influenced by previous events therfor making every action a reaction. But if one would have all the knowledge in the universe, would he be able to predict the future for 100% correct?
We lack sufficient data to predict with absolute accuracy. The question here is what factors contribute to accurate prediction.
Vanlavak said:Randomness is only random in perspective and ignorance to the "bigger picture" of the sum of all the facts.
That appears not to be the case, which is the whole point of quantum indeterminacy. It seems that the universe is not actually deterministic. Counter intuitive, but apparently so.
The thing is that we cannot know everything. Our knowledge of the position and velocity of a particle is limited by the Heisenberg uncertainty principle. This states that the more accurately we measure the position of a particle, the worse we are able to measure the velocity of the particle and vice versa. Therefore someone with all the knowledge in the Universe would still not be able to determine the exact position and velocity of every particle and hence we cannot know the future for certain. The next best thing we can do is to know the wave function (function that dictates the probability of a particle existing at a particular point in space or having a particular velocity) for every particle and from this, determine the most likely future/s of the Universe.
At least this is my recollection of things after a university course and a couple of Stephen Hawking books. Admittedly though, all were done/read 2 or 3 years ago so I'm a bit rusty. If I'm wrong on some (or all) count/s please correct me!
At least this is my recollection of things after a university course and a couple of Stephen Hawking books. Admittedly though, all were done/read 2 or 3 years ago so I'm a bit rusty. If I'm wrong on some (or all) count/s please correct me!
Unless I'm mistaken quantum indeterminancy and the heisenberg uncertainty principle govern different areas. The heisneberg uncertainty principle relates to the fact that you cannot measure the precise state of the Universe, for the reason you have given, it's not possible to measure it without affecting it.
Quantum indeterminancy, as I understand it, states that even if it were possible to know the current state, we still wouldn't be able to predict subsequent states other than as probabilities.
Quantum indeterminancy, as I understand it, states that even if it were possible to know the current state, we still wouldn't be able to predict subsequent states other than as probabilities.
D
Deleted member 619
Guest
Squawk said:Unless I'm mistaken quantum indeterminancy and the heisenberg uncertainty principle govern different areas. The heisneberg uncertainty principle relates to the fact that you cannot measure the precise state of the Universe, for the reason you have given, it's not possible to measure it without affecting it.
No, Heisenberg's Uncertainty Principle is a formal description of quantum indeterminacy, and is the principle that underlies it.
Basically, it isn't just about measurement. As far as we can tell, a particle doesn't actually possess a position or a velocity until we measure it. Measuring defines whichever one you're looking at. Certainly the 'observer effect' has some part to play in this, but it's often overstated.
It should also be noted that HUP also applies to fields, so that we can't know the value (position) of a field and its rate of change (velocity) at the same time.
It should be noted that the way that the word 'random' applies here doesn't necessarily mean 'uncaused', but relates to statistical independence, which is to say that, to take the decay of a radioactive isotope as an example, that it may decay in a split second or a million years, or at any time in between. It is inherently unpredictable. This is also governed by HUP.
Quantum indeterminacy, as I understand it, states that even if it were possible to know the current state, we still wouldn't be able to predict subsequent states other than as probabilities.
Indeed. But this is still a manifestation of HUP.
It's a tough one to get your head around, but QM is reasonably straightforward to grasp in a visceral sense once you get a grip on HUP. Mathematically, it's a different matter, but it's simple enough to grasp, at least in principle, once you understand all the implications of indeterminacy, which is the central governing principle of QM. Everything flows from this uncertainty, including quantum tunnelling (the principle that governs the behaviour of microchips), reflections in a clear window (which is actually a manifestation of the same principle underlying quantum tunnelling), the double-slit experiment, etc.
Tunneling is the primary means of electrons passing through the oxide layer in MOS technology. It is undesirable as it increases power consumption of the device. There are only a few places that tunneling seems to be used to a device's benefit:hackenslash said:...including quantum tunnelling (the principle that governs the behaviour of microchips),,,,
http://en.wikipedia.org/wiki/Tunnel_junction
Slightly off topic, yes, but device engineering and electronics are things that I do know a bit about so I thought I might comment on this.
EDIT: To clarify the point of this post, the point I was making was that quantum tunneling is NOT the principle that governs the behaviour of microchips.
devilsadvocate
New Member
Isn't the probability of certain particles due to lack of knowledge?
Particles really behave like (probability) waves, uncertainty principle has far more elemental implications than simple measurement inaccuracy. One very fundamental consequence is the electron cloud model. Wave-like property of electrons explain the discreet energy levels they can take "orbiting" the nucleus of an atom. Electrons can only exist at an energy level (frequency) which forms a standing wave. Without the wave-like property of electrons atoms wouldn't work!
CosmicJoghurt
New Member
RigelKentaurusA said:It's more than just a lack of knowledge. Consider the double-slit experiment... that interference pattern shows up even if you fire photons one by one.
http://www.youtube.com/watch?v=wEzRdZGYNvA
Hmm.. and I thought it was only an electron-driven experiment. I did some searching now... same thing happens with photons...
Someone here on the forums posted a link to a wikipedia article on an another double slit experiment, using photons, and it had to do with putting crystals and mirrors around the place so they could measure exactly through which slit the photon went. But this observation was executed at the end of the path, not while they were going through the slits, but afterwards. Each mirror set corresponded to a specific trajectory....
If anyone recalls what the name of the experiment was, please share it.. it's very interesting...