"Causality" or "determinism"?
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From: Remus Shepherd on 5 Mar 2010 12:03 In rec.arts.sf.science Tue Sorensen <sorensonian(a)gmail.com> wrote: > On 5 Mar., 15:52, Remus Shepherd <re...(a)panix.com> wrote: > > ? ?Causality is to determinism as traffic rules are to the highway system. > > If people follow them, the roads work as intended. ?But we can't guarantee > > that everyone follows the rules. > As far as the laws of physics are concerned, isn't it reasonable to > presume that the rules will be followed? Of course, I realize it > depends on how accurately we understand the rules... But some of the laws appear to be, 'Do whatever you want'. :) A particle in a superposition of quantum states ends up in one chosen at random. There may be a means by which consciousness forces quantum states into a directed collapse. (See the Quantum Zeno effect.) It isn't deterministic when part of the rules say to roll dice and consult a table in a DM's guide somewhere. You can't predict what's going to happen in that case. If there is randomness or free will (which, in physics terms, may as well be randomness) then determinism doesn't exist. > > > Do we need to define simplicity/ > > > complexity any further than to degree of atomic/biological/ > > > technological organization? > > > > ? ?No, that's why context was invented. > So does it make adequate sense to say that hydrogen fusion in a star > is a simple process (all the circumstances, like gravitational > pressure, considered) while life on Earth is highly complex? Again you need context. To a janitor, hydrogen fusion might be beyond his ability to grasp while his understanding of life on Earth comes down to 'garbage in, garbage out'. Complexity and simplicity are subjective. > > ? ?Think of a dollar and an anti-dollar colliding and bursting into flame. ? > > You might think you have $0.00, but the energy of their conflagration is > > worth something > A lot of cents and pennies? :-) > > -- possibly more than the $2 you started with. > Okay, this I have to inquire about: where does this "possibly more" > come from? Because mass can be converted to energy, and vice versa. If the particles are in a low-speed collision, you only have their mass and a little bit of kinetic energy to work with. But if they're in a high-speed collision, they have a lot of energy, and their total energy (mass + kinetic) might be enough to create something with much more mass than the original particles. But, of course, it will have much less velocity. > > > If the particles really become energy, do we know exactly how? > > > > ? ?They don't 'become energy'. ?They cease to exist. ?Conservation of > > energy says that the energy has to go somewhere, so the universe uses it > > to make new particles. > But we can describe electromagnetic radiation as pure energy, can't > we? You can describe things any way you want. :) The limitations are in our language, not in our understanding. (At least, not on this level. Go a little deeper and our understanding gets fainter.) > When particles annihilate, much of the energy they contain will be > released as EMR, right? EMR is made of particles -- generally photons. When particles annihilate, they turn into particles (mass) with some kind of velocity (kinetic energy). There's no such thing as 'free floating energy'. It is bound up in either mass, kinetic energy, or potential energy. (Note that potential generally cannot be created in collisions.) > :-) So, all we need is to rephrase our theories? That wouldn't work if we're rephrasing them in the same old language. We would need a new language to make quantum physics any clearer than it is. But English does the job okay, especially when we invent new words (quantum, quark, neutrino, etc) to exemplify new concepts. .... ... Remus Shepherd <remus(a)panix.com> Journal: http://www.livejournal.com/users/remus_shepherd/
From: Tue Sorensen on 5 Mar 2010 12:07 On 5 Mar., 16:59, rotchm <rot...(a)gmail.com> wrote: > On Mar 4, 8:37 pm, Tue Sorensen <sorenson...(a)gmail.com> wrote: > > > I have a few questions that I would like people's expert input on... > > > 1. Don't the terms "causality" and "determinism" actually mean the > > exact same thing? > > No, the concepts and definitions are different. > Here are two examples where: > > 1) Non-causal deterministic situation: Midway between two distant > firecrackers an observer sends a light signal to explode the fk's. > They thus explode simul. > > This is a deterministic situation, in that knowing the rules > ( observer sends signal, fk's setup to explode on reception of signal) > we can predict what will happen: if observer sends signal, the fk's > will explode simul. However, the two events "explosions" are non- > causal events. A consequence of them being non causal is that there > exists inertial frames where one explodes first then the other, and in > other i-frames, its the other that explodes first...Causality is also > about time ordering. > > 2) causal non-deterministic situation. Two fk's are setup such that > the right one is set to only explode ( with probability 99.99%) when > it receives the "explosion" of the left one. i.e. the right one should > explode but due to qm, it may not with probability 0.01%. > > This is a non deterministic situation because the rules are non- > deterministic. The individual outcomes can not be predicted. However, > the explosion of the right fk is causally connected to the left fk. If > the right fk explodes then we can conclude that the left one has > exploded too, and *prior*. A consequence of this is that in *any* i- > frame, the two events ( explosions) will remain causal, will keep the > same time ordering: Left explodes before the right one. > > Now, on to a concise definitions ... Ouch, getting very woolly there... So, anything governed by probabilities is not deterministic? And causality is only something you talk about as part of a simplistic model (like an experimental set-up) or closed system where only a couple of isolated causes and effects are involved. So causality cannot be described as a general law that amounts to everything in the universe simultaneously obeying the comprehensive principle of (interdependent) cause and effect? - Tue
From: Wayne Throop on 5 Mar 2010 12:13 :: Now, the question is: what does 'real' mean? Actually, this is not :: as easy as you think. 'Real' means something like observable. But :: relativity tells us, that observations are depending on the point of :: view, hence on the observer. I would guess, this would include the :: 'realness' of particles, too. That turns out not to be the case. Relativity in and of itself deals in an objective universe. But don't worry, it's a common misconception. Given a time machine, it would probably be a mitzvah to go back and rename it "invariant theory" instead of "relativity theory". And also, get people to talk about "observers" less and coordinates more. For an analogy, I can observe that object X is to the right of object Y. Fred, across the room there, observes that Y is to the right of X. Does that mean that the "real"ness of X and Y are called into question? No. No it doesn't (you will hopably agree). Similarly, in relativity, one feller observes clock A is slower than clock B, but another feller observes clock B is slower than clock A. Again, is the reality of the clocks, or any of their ticks, called into question? No. No it isn't. Consider the barn-and-pole so-called-paradox. Somebody sitting on the ladder uses coordinates in which the barn is shorter than the ladder. Somebody sitting on the barn uses coordinates in which the ladder is shorter than the barn. But at the end of the day, both agree that both ends of the ladder miss both barn doors. They just disagree on the precise reasons and timing, just as they might disagree which object is to the left of another. Bottom line, barn, ladder, and the operation of both barn doors, is all entirely objective, even though whether the barn or the ladder is longer is not. Similarly, in considering the twin so-called-paradox, the ages of both twins when they meet again are entirely objective, even though the clock rates at various events along the way are not. Wayne Throop throopw(a)sheol.org http://sheol.org/throopw
From: Thomas Heger on 5 Mar 2010 12:36 Tue Sorensen schrieb: > On 5 Mar., 14:00, Thomas Heger <ttt_...(a)web.de> wrote: >> Tue S rensen schrieb:> On 5 Mar., 03:55, Thomas Heger <ttt_...(a)web.de> wrote: >>>> I would guess, that the very idea of fundamental particles is wrong. We >>>> have particles, but those are -in my view- certain structures, that we >>>> can identify and model, but they are not 'real' in the sense of distinct >>>> and separable entities. >>> Well, in order to make up a real macroscopic world, they must become >>> real at some point... >> Now, the question is: what does 'real' mean? Actually, this is not as >> easy as you think. 'Real' means something like observable. But >> relativity tells us, that observations are depending on the point of >> view, hence on the observer. I would guess, this would include the >> 'realness' of particles, too. > > But presumably there is still a single universal frame of reference, > isn't there? Otherwise we're getting into absolute idealism; that > reality is created by the observer, which negates objectivity (and > hence most science). No, it's not that though. I think, that what we usually call 'real' depends on our point of view. But it's not created by our observation. We observe something, that is the same for all observers. But the observations are different. Guess, you see me and I see you. Than we have different impressions, but don't create each other. So we had to build the world out of invariants. That are in GR terms intervals. I prefer complex-four-vectors for this purpose. That is a bit counter-intuitive, but would make some sense. They are sometimes called bi-quaternions. They have a subset called quaternions. These constructs are great for intervals. Now, believe it or not, it is possible to model atoms and particles with these numbers. It's not particularly easy, but possible. If you like to learn more about this model, I would recommend Peter Rowland: "Zero to Infinity". Or - of course- my own paper. Its a bit amateurish, but easier to understand and you may find it here: http://docs.google.com/Presentation?id=dd8jz2tx_3gfzvqgd6 Greetings TH
From: Wayne Throop on 5 Mar 2010 12:47
: Tue Sorensen <sorensonian(a)gmail.com> : Ouch, getting very woolly there... Meh. Doesn't seem that complicated to me. Causality is all about relationships between events (and their time-ordering). Determinism is all about whether the effects of a given cause are necessarily unique. Or put another way, causality says that after the fact, effects have specific causes. Determinism says, that even before the fact, all causes have specific effects. Sort of. : So, anything governed by probabilities is not deterministic? The notion of being "governed by probabilities" will likely lead to misunderstandings and such. Because "probability" is most often used to mean "it's real complex and I don't have enough information", not "there's no information to be had". In QM, the assertion is that there's no additional information to be had; no "hidden variables". So that the effects of a given cause aren't unique, even if you know everything there is to know about all the causes involved. So, in QM, the notion is that even if you know everything about the the state of some experimental apparatus containing a photon emitter and a target, you can't tell where any given photon will hit the target until after it gets through the interference slits. But that doesn't mean the emitter didn't cause the scintillation in the target. Wayne Throop throopw(a)sheol.org http://sheol.org/throopw |