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From: Mitchell Jones on 26 Jun 2010 15:42 In article <Ou2dnSrelu1cer_RRVn_vwA(a)giganews.com>, Tom Roberts <tjroberts137(a)sbcglobal.net> wrote: > Robert L. Oldershaw wrote: > > On Jun 21, 4:26 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > >> If you don't believe me, just try to resolve the issue I brought > >> up earlier using any of those theories: what is the "cause" of > >> the fire on this match? > > ---------------------------------------------------------------- > > > > Well, for starters how about: motion, then friction, then heat, then > > chemical reactions, then fire? > > Are you saying that going from an unlit match to a flaming match is an > > ACAUSAL process? > > No. > > > > What exactly is your point? > > That you cannot actually specify the cause of that fire. And therefore, you > cannot construct a sensible physical theory based on such "causes". Your > usage > of "causality" is NAIVE, and no modern physical theory has it, except > possibly > as an approximation. > > > > Can you specify any physical system undergoing any specific physical > > interaction that violates causality. > > I'm not sure what "violates causality" means. ***{The notion of an uncaused event violates causality. An example would be an object changing its state of motion without the action of an external force, or--and this amounts to the same thing--a force leaping into existence out of nothing, rather than being carried by an entity. The importance of the law of causality lies in its message: it tells us that, if we think we are seeing an uncaused event, we need to think again, investigate further, until we can see how the effect arises out of the interaction of its antecedents. It serves us well in a universe where there are lots of important events the causes of which are presently unknown, but in which there are no events that are truly uncaused. --MJ} > There are certainly many > non-causal systems for which we have good physical models. Such as classical > electrodynamics, in which charge does not "cause" the field, and the field > does not "cause" the charge, and yet charge and field are 100% correlated via > Maxwell's equations. ***{Sometimes understanding of a cause enables us to write an equation. Suppose, for example, that it is 1 pm and I get a call from a friend who says he is pulling out of his driveway and will be at my house at 3 pm. The cause of his getting to my house will lie in (a) the fact that he has a working automobile, (b) the fact that he has access to the fuel he needs to run it, (c) that roads exist on which he can travel to get to my house, (d) the fact that he is capable of operating an automobile, and (e) the fact that he intends to use his skills, fuel, and the available roads to get to my house. Result: I can write VT = D, set T = 2, and, by finding the best route on a map and determing that, say, D = 117 miles, I can find that his average speed will be V = D/T = 117/2 = 58.5 mph. Note, however, that the equation and the cause are not the same thing. Understanding of the cause enables us to write the equation; but the ability to write the equation tells us very little about the cause. Awareness of causation, in short, requires awareness of the details of a phenomenon. When all one has is an equation, those details are lost. In the age of classical physics, people were mainly focused on the world of experience, the macrocosm, and as a consequence mainly arrived at mathematical relationships by means of causal analysis--i.e., by investigating the details of a phenomenon to determine its component parts and how they interacted to produce the effect of interest. Once the components and how they interacted--i.e., the cause--had been understood, the equations followed as a matter of course. Nowadays, experimental physicists are often focused on the microcosm, where most of the details of phenomena are not yet accessible to us. Result: in most cases only correlations between the few things that we can measure are available. Hence we often can only say that A is likely to be followed by B, and can only write equations expressing such likelihoods in probabilistic terms. Lack of awareness of causation, however, is *not* the same thing as lack of causation. It is also worthwhile to note that even in cases such as the above example, where the average speed was calculated based on awareness of distance and time, the idea of necessary connections across the time-sequence of events rests on assumptions. The necessity, in short, lies in the relationship between the premises and the conclusion. If, for example, my friend changes his mind, or cannot carry out his intent due to his car breaking down, a bridge being out, etc., then he will not arrive by 3 pm, and all bets are off. Thus even under the regime of classical physics, certainty was only possible to the extent that one could be sure that the required causation was present. Uncertainty about what causal factors will interact to produce an effect, however, is not the same thing as uncertainty about whether an effect is caused. --Mitchell Jones}*** > Note that classical electrodynamics does indeed have causality in the modern > sense ***{There is nothing "modern" about equating correlation, including perfect correlation, with "causation." David Hume argued more than 200 years ago that perfect correlation, which he termed "constant conjunction," was the best we could do, and that apprehension of necessary connections within a time-sequence of events was impossible. His conclusion was that the principle of scientific induction--that things will behave in the future as they behaved in the past--was an article of faith, resting on nothing, and that science, as a consequence, rested on precisely the same grounds as religion. Your notion of causation "in the modern sense" is merely an admission that the Humian point of view has prevailed, and that the term "modern science" has, as a result, become an oxymoron. --MJ}*** > -- it is not naive, and is not subjective like your usage: the field at > a given point depends only on the charges and field within its past light cone, > and is completely independent of everything outside its past light cone. > Another aspect is that timelike-separated events have a definite order (independent > of frame), while spacelike-separated events do not. > > Note that this meaning separates things which can affect the > fields at a given point from things which cannot. But it makes > no attempt to specify what "is" the "cause" of the field(s) at > that point. Indeed in GR and classical electrodynamics, the > relevant field(s) everywhere within the past lightcone can be > said to "cause" the field(s) at that point (but one must be > speaking rather loosely). > > This is not at all what you mean by "causality". So beware of PUNs. > > The NAIVE causality you espouse arises in these theories when > there is only a single object within the past lightcone that > has nonzero field(s), so it is the only thing which can affect > the field(s) at the point in question, and thus can be said > to be the "cause" of those field(s) in the naive sense. ***{There is nothing "naive" about the idea that no thing may come into existence out of nothing or vanish into nothing (the principle of continuity), and that, as a consequence, all forces are exerted by entities in collision, and that, as a further consequence, everything which happens (every effect) arises out of the interaction of a specific set of entities, and that the interaction in question constitutes the cause of the effect. The reality is (a) that we live in a mechanical universe driven by an inexorable causality, and (b) that those who deny that state of affairs are not "naive," but simply wrong. --MJ}*** > > Tom Roberts ***************************************************************** If I seem to be ignoring you, consider the possibility that you are in my killfile. --MJ
From: Mitchell Jones on 26 Jun 2010 16:14 In article <i011p0$ko8$1(a)news.eternal-september.org>, "hanson" <hanson(a)quick.net> wrote: > "Tom Roberts" <tjroberts137(a)sbcglobal.net> wrote: > > Robert L. Oldershaw wrote: > >> Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > [snip bantering over timely minutia] > > > hanson wrote: > It all boils and gets down to the properties of a definition for > time, which is by definition anthropic & hence questionable > in the greater and deeper scheme of things. ... > So, for human povs and purposes, if you elect to define that > = Time is the sequential occurrence or manifestation > = of events, items or processes in nature = > then all your petty arguments fall away. You can even set > restrictive sub-definition that allows time to be what is useful > in your experiment... since sequences can go back and/or > forwards, (arrow of time), accelerate or dilate, be periodic > or aperiodic etc, etc... Why all the big deal about time. > Thanks for the laughs, though... ahahahaha...ahahanson ***{Time is that which is measured by a standard clock and by every other clock which has been designed to match the readings of a standard clock. The acceptance of this definition is, for example, why a clock intended to be used in a GPS satellite is designed to lose 38 microseconds per day when at sea level: the goal is that it match the readings of a standard clock on the ground, while it is in orbit. Since it will speed up by 38 microseconds per day when placed in orbit, it has to lose 38 microseconds per day while on the ground. The implication: time advances at the same rate throughout the universe, by definition. If, due to your velocity or the intensity of the gravitational field in which you are immersed, or both, or if due to any other cause whatsoever your clock fails to match the readings of a standard clock, all that tells you is that your clock needs to be set. Absolute time--time that advances at the same rate throughout the universe--is the only concept of time that works in the real world. If the relativists don't like that, let 'em howl. The reality is that their precious GPS would not work, if clocks in the GPS satellites were not designed to advance at the same rate as standard clocks on the ground. Result: they are hoist by their own petard. --Mitchell Jones}*** ***************************************************************** If I seem to be ignoring you, consider the possibility that you are in my killfile. --MJ
From: eric gisse on 26 Jun 2010 20:29 Robert L. Oldershaw wrote: > On Jun 25, 8:38 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> >> Its' your belief that ignorance is a form of knowledge. You know nothing >> about modern physics but you feel you have a better grasp of the subject >> than actual physicists. > ------------------------------------------------------------------ > > Well, even though I probably know more physics than you [...] Since I have formal training in the subject and you don't, I rather much doubt that.
From: Robert L. Oldershaw on 26 Jun 2010 21:57 On Jun 26, 8:29 pm, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > > > Well, even though I probably know more physics than you [...] > > Since I have formal training in the subject and you don't, I rather much > doubt that. ----------------------------------------------------- But you are more than a little uncertain about that, aren't you Woofster? RLO http://www3.amherst.edu/~rloldershaw/menu.html
From: Sam Wormley on 26 Jun 2010 23:25
On 6/26/10 8:57 PM, Robert L. Oldershaw wrote: > RLO > http://www3.amherst.edu/~rloldershaw/menu.html > > Some perspective, Oldershaw http://en.wikipedia.org/wiki/Fractal_cosmology |