Why do quantum mechanics rule out determinism? Yes, we are epistemically limited by them, they make it impossible to know the present conditions, but why does that mean that if we did know them we wouldn’t still be able to predict the outcome. No event occurs without sufficient cause, and if sufficient cause is present the event must occur. This is simple causality, and I see no way that quantum mechanics can run an end-around to avoid it.
Schroedinger’s Cat is either alive or dead, it’s not a wave-form of the two possibilities. That’s simply preposterous. I suspect that quantum mechanics is the result of ignorance, physicists who don’t know what’s really going on and how the forces really interact, so they made a patchwork quilt of possibilities to explain away their own shortcomings. Remember the early cosmologists/astronomers and their intricate series of interlocking circles they used to explain the motion of astronomical bodies? They were covering for ignorance, the system looked complex because they didn’t know the truth of heliocentrism. When we know what’s really going on, all this talk of “possibilites” will fade away and reveal a classical modernist system that makes actual sense.
And I echo the points above about the sort of “free will” that randomness would allow, it’s not really free at all. We certainly appear in our day-to-day existence to have free will, so for existentialists that’s all that matters. I’m a determinist, but this doesn’t really affect my behaviour too much because for all practical purposes I’m not in a position to determine the outcomes. Still, I have no idea why so many people keep coming back to the idea of free will as an actual truth about the world, when that idea is revealed to be nonsensical with just a simple understanding of causality. You don’t ask the rock falling off a cliffside if it can choose it’s place of landing, but our personal bias as existing conscious individuals makes us dare to claim that we’re different. Crazy.
This is great, you-all are helping me clarify my idea of free will a lot.
Let’s put it this way: an entity whose future behavior can be predicted accurately and non-probabilistically has no free will.
(Note that I’m not asserting that anything unpredictable has free will, which would give electrons in QM free will.)
Now, in classical mechanics, everything can be predicted, given sufficient information about the initial conditions. (Sentient: there is no restriction on this knowledge in classical mechanics. See my post above on chaos.) So in the classical universe nothing can have free will.
QM gets us out of this in two ways:
Complete knowledge of the initial state is only possible for systems that can be repeatedly reproduced. This is not true of the universe, nor even of a single human.
Even if such knowledge were available for a human, QM only gives probabilistic predictions.
This doesn’t prove that we have free will. But it does free us from the classical world where free will is impossible.
RexDart: Believe it or not, the statement “Schroedinger’s Cat is either alive or dead, it’s not a wave-form of the two possibilities” has experimentally testable consequences. Read up on “Bell’s Inequalities”. You can only assert this if you are willing to accept that some physical influences travel faster than light.
It’s allright if these quantum mechanics enthusiasts admit that they can’t predict it, it’s another thing entirely to assert that it cannot be predicted. There are alot of things cavemen probably thought were unexplainable, incomprehensible and mysterious that we now can explain and predict quite simply. This talk of “possibilities” smacks more of ignorance than it does an affirmative theory. So just because physicists of today are ignorant, why let them cover for it by saying, “uh, well, you see, I can’t predict these events because, um…nobody can predict them, yeah, that’s it!”
If I were a physicist who discovered that I was unable to predict an event, and was left with only possibilities (i.e. inaccuracies, let’s call 'em what they really are), I would decide my theories were flawed and discard them until I found ones by which I could predict the event.
If I repeatedly threw a rock off a cliffside at a certain angle and initial velocity, I would expect the rock to fall in the same place every time. It clearly ought to. But if I conducted the experiment and found that wasn’t the case, would I claim that the trajectory of objects was unpredictable and merely a range of possibilities?? No, I would find the effect I was ignoring. Eventually I’d realize, “ahhh, I forgot to factor in the wind and/or air resistance”, adjust my experiment so that I could account for that, determine it’s effect, and then repeat the experiment. I could continue to do this as many times as needed, refining, learning about the world, until eventually I was able to get identical results with identical initial conditions.
I doubt you could ever get identical results or identical conditions.
You can’t step in the same river twice.
The rock cannot land or depart from the same place twice, or go through the same air space, etc. Temporarily it’s not even the same rock. There’s no such thing as two identical events or things.
Posted by ** Apos**
I think I agree.
i.e. If we don’t know who it is that knows or decides then how could we have free will? We don’t know who has it.
Then you must be using a different standard of comparison each time. That being the case, it is not surprising you’d come up with such a conclusion. Unless you are using the same standard every time, in which case you’re just wrong.
RexDart: On what basis do you assume that quanta act like rocks?
I know, it would be so * nice* if an electon acted like a dust speck which acted like a rock which acted like a cannonball which acted like a planetoid which acted like a galaxy. They don’t.
They’re all merely matter and energy, just some of those items are smaller and made of different arrangements of teenie bits. Obviously one might expect them to appear to act differently because of our limited abilities to ascertain the proper knowledge of their present state, but not fundamentally differently. If simple deterministic causality explains the behaviour of all the objects larger than an electron, and it does, what’s so special about everything smaller than that such that it not only behaves differently, but supposedly doesn’t behave predictably at all? Why should the size of an electron be a threshold between predictable and unpredictable behaviour, what’s special and unique about that exact size that can logically explain this difference so fundamental that it tears at the very metaphysical underpinnings of our universe??
Logically, causality is foolproof, and so is the principle of noncontradiction. Either a given object is at a certain location, or it isn’t at that location. Perhaps the seemingly random effects are a result, as I believe, of a poor understanding of what’s actually going on. Scientists aren’t observing the actual objects, they’re observing the effects of those objects, and they lack a proper framework in which to put those effects into the underlying causal system. If your computer spat out a string of seemingly random numbers, would you assume your computer had somehow managed to defy prediction? No, you’d look for the algorithm it’s using and find the starting value and then you’d be able to predict the sequence with complete accuracy. Anybody who even briefly dabbled in programming languages from BASIC onwards would know this.
RexDart, thank you for pointing out the flaws which render the combined work of the finest minds of the twentieth century irrelevant. Now if you could just explain why the Young’s double slit experiment works for electrons as well as light waves I’ll have the jewellers inscribe your name on the Nobel Prize for Physics ASAP.
RexDart: Ignore the snide comments if you like: you are in good company. Albert Einstein voiced similar objections to QM.
Think about the following, tho. You say
This is an assumption. You believe this because your experience with macroscopic objects leads you to. How do we even know what matter and energy are? When you say the items are “just smaller” you are assuming that size doesn’t make any difference. What if that assumption is wrong?
Also, you say
How do you know this? Why can’t things simply be random? You are again extrapolating from your experience to a realm far from your experience. In effect you are saying, “I know everything I see around me follows deterministic laws, therefore everything follows deterministic laws.” What if that extrapolation is simply wrong for the subatomic world? Even a sentence like
assumes that an electron (say) is an “object”, something that comes loaded with associations. What about a water wave? Could you say “Either the wave is at a certain location or it isn’t”? How do you tell if you have one wave or two? The concept of the “location” of something isn’t applicable to a wave. Nor is it applicable to an electron (if QM is right).
To deal with these phenomena you have to expand your mind!
I feel pretty safe concluding that all matter is composed of some fundamental particle, which apparently is quite small and we may not have discovered yet.
My problem with the idea of bigger/smaller being so different is that QM says that all things above a certain size act one way, all things below that size act a different way. It’s a threshold. When you posit a threshold, you have to be ready to explain exactly why that precise value is the threshold between two radically different types of behaviour. Why isn’t the threshold higher, why isn’t it lower, why is it there at all? For what reason is the threshold between deterministic and probabistic behaviour at exactly the place you are finding it?
Well, randomness is precluded by the very definitions of cause. Sufficient cause is defined as those events which force the effect to occur, and without which the event cannot occur. Definitions precede observations. Now, it so happens that the definitions of cause and effect work in explaining the observable world. If you want to say that somehow these subatomic particles, simply by virtue of being smaller, somehow manage to throw off the shackles of causality, then do you mean to junk the idea of causality entirely or modify it?
Causality is not simply a matter of observation, it’s a metaphysical assertion about the way our universe works fundamentally. If philosophy finds something to be logically impossible, no scientist will ever be able to accomplish it. For instance, if we were to demonstrate with logic that time travel is impossible, then it doesn’t matter how long and hard scientists work on it, they’ll never be able to travel in time. Metaphysics precedes physics.
In fact, without causality, how do you even do experiments? If causality is tossed on the scrap heap, then all you could really do was observe things (and considering it’s QM we’re talking about, you couldn’t even do that very well.) To actually form a theory about the observations, you’d have to explain why something happens, which this quagmire of randomness you’ve created can never do.
A “wave” is just an artificial construct of language. There is no wave. The ocean contains numerous particles of water, each of which is in a certain position with a certain momentum at a certain time. That position and momentum determines it’s next position and momentum after considering the forces acting upon it. If we break up these constructs of language, we find the fundmental pieces that have been forced into the linguistic construct, and we deconstruct the artifice to get to the reality.
Without causality, reasoning is worthless. To expand one’s mind to encompass quantum mechanics ideas would be to destroy the very fabric of our understanding of the world, make the world incomprehensible, and therefore all our endeavors to relate to the world utterly futile. If quantum mechanics is true, we could never meaningfully assert its truth, because QM destroys truth, falsity, and reason by creating a world that embraces contradictions. It would be like asserting “no sentence is ever true or false”, an assertion that destroys its own idea and thus can never be meaningfully asserted. If we accept QM, we might as well throw up our hands and just give up, because nothing we “discover” will ever be of any use and we can never even approach certainty of it.
I hope there are scientists out there who reject QM, and are working still today to find the causal pattern behind the seemingly random observations. It seems like the height of folly to see observations that are unpredictable with your present knowledge and then just say, “well, they’re supposed to be unpredictable”, rather than continuing to look beyond the observations until the knowledge is found to predict them. The 400 year quest of modernism to explain the universe is about to be thwarted by a bunch of quitters who would rather embrace the convenience of unpredictability than to continue the quest for knowledge of our universe. Kepler could have just given up and said, “we’ll never be able to explain the motion of the astronomical bodies”, but instead he did the work and found the pattern and the explanation.
QM is the cancer on physics as postmodernist antirealism is the cancer on philosophy.
Rexdart, it appears to me that you are making a very large number of assumptions. For instance, you assert:
From your other statements, I believe that you assume these fundamental particles must behave according to the rules of classical mechanics.
What you believe is essentially what all scientists believed at the beginning of the twentieth century. Scientists did not abandon these deeply-held assumptions on a whim, but rather these beliefs were torn from them by a growing number of experimental results that simply could not be explained without abandoning some of the fundamental tenets of the existing system.
Classical mechanics cannot explain quantum behavior. FriendRob mentioned Bell’s Inequalities. These are essentially a proof that any possible system of physics that assumes that particles have precise values for such attributes as position and momentum (known as a “hidden variables” theory) and that does not violate causality (including the notion that no influences propagate faster than light) must make certain predictions that differ from the predictions of quantum mechanics. This has been tested, and the predictions of quantum mechanics have been borne out.
I agree that the idea of a precise threshold, below which behavior is entirely quantum and above which behavior is entirely classical, is aesthetically displeasing. I do not deign to assert that it is necessarily impossible, but the universe would be far simpler if all systems obey the same fundamental rules. I believe that in fact they do, and that these rules are the rules of quantum mechanics. Everett’s “relative-state” or “many-worlds” interpretation asserts that all dynamics are governed deterministically by the same Schrödinger equation that governs quantum phenomena. I believe that this interpretation resolves many of the complaints that Einstein had about quantum mechanics. Recent research has gone very far towards showing why larger objects exhibit behavior that appears classical, though there is no precise dividing line. In fact, quantum computers can be said to work by exploiting the strange behavior that exists for phenomena on the boundary between strictly quantum and strictly classical.
Though this theory is attractive, I do not imagine that I hold some special insight into the inner workings of the universe. I make assumptions on the basis of Occam’s Razor; that the simplest theory compatible with observations should be regarded as true. I do not pretend to know that this theory will remain compatible with all future observations. Furthermore, I am aware that the idea of simplicity is itself subjective, and that a different person confronted with the same evidence might find a different explanation to be simpler in his or her mind.
You believe that philosophy trumps physics–that if something can be shown to be false by philisophical standards and true by physical standards, the physicists must be in error. I believe otherwise. In my opinion, physics trumps philosophy. Philosophers frequently make a priori assumptions based on what seems reasonable to them, but what seems reasonable to any given person need not necessarily correspond to what is true in the real world. Human intuition evolved to deal with problems that are quite different from those we face in particle physics. Philosophers have a long history of firmly believing in things that were later proven wrong by the advance of science. Physical experiments must be interpreted by human beings, but they are still connected in a very direct manner to whatever passes to absolute truth in this universe of ours. Their results are far more trustworthy than is uninformed speculation like yours.
RexDart: Apologies for my snideliness, it’s just that this thread reminds me of drunken nights with my Programmer friends who would endlessly compare any physical system to a computer!
No, there is no such threshold. All bodies obey QM, it is just that for macroscopic bodies the probability of them being observed “behaving in a quantum way” is such that it is unlikely to ever happen within the lifetime of the universe. The electrons and such which comprise the object act “quantumly” all the time, but the net effect is zero. QM does not violate the Correspondence Principle.
QM does not dispose of causality altogether, it states that there is a fundamental limit to the accuracy to which one can measure certain characteristics of a system. The more accurately you know the momentum of a particle, the less accurately you can know its position, and vice versa. If you built a TV ignoring this Uncertainty Principle, the picture would be rubbish. This is a fundamental limitation rather than a limit of the equipment, I assure you.
How come we can see the sun through 90M miles of vacuum? A “wave” is a perfectly good mathematical description of the propagation of energy. In the same way, if I drew a square in the sand, I could point at it and say “there is a square” rather than “there is some sand”.
Take heart, I felt exactly the same way the first time I studied the Young’s double slit experiment for electrons in first year physics, and Einstein hated it all his life (but still accepted it). QM is just so wrong! My advice would be to read around the subject a little, come up with your own questions and hopefully, eventually, realise that some of the cleverest people in the world haven’t been wasting their time for a century.
