matt@oddjob.UChicago.UUCP (Matt Crawford) (04/26/84)
Regarding uncaused causes: The recently revived "Kaluza-Klein" theories, turn non-gravita- tional interactions into geometrical effects by the introduction of additional dimensions which are assumed to have compactified to small ( ~ planck length ) sizes. Popular versions involve a total of 11 dimensions. If there were, say, 3 timelike and 8 spacelike dimensions then there would be no causality at high energies. Then there would be no need to find a cause for the big bang. Of course, there are other possible objections to the idea of 8+3 dimensions than just causality.
rcd@opus.UUCP (Dick Dunn) (04/26/84)
<mumblegrumblemuttermutter...> >You guys are doing great work. More bombs please... Hmmm, talk about opening a still-raw wound...better go ask that one in net.politics. Nukie bombs are the reward we all got when Einstein made the mistake of trusting a politician... >AND HOWEVER FAR YOU TRACED THE STORY BACK YOU WOULD NEVER FIND THE LAWS OF >NATURE CAUSING ANYTHING. (italics mine) > >The dazzlingly obvious conclusion now arose in my mind: IN THE WHOLE HISTORY >OF THE UNIVERSE THE LAWS OF NATURE HAVE NEVER PRODUCED A SINGLE EVENT... > . . . the source of events must be sought elsewhere. You got it! If by "laws" you mean the body of postulates and the theory derived from postulates, etc., you're right - they constitute an abstract model. Abstractions have a hard time influencing reality. (No, wait, if a tree falls in the forest because it was cut to make pulp to print a physics text, you might say that the laws of nature were responsible.:-) But seriously (maybe:-), "...the laws of nature causing anything..." is grammatically correct but not meaningful, so it's impossible to say yes or no (I know, I should say it isn't imparseable but there's some antics with the semantics). >The smallest event, then, leads us back to a mystery which lies outside >natural science. Do you mean to posit unnatural science? Not on my terminal, you won't! Actually, you get to trace everything back to the situation of the singularity at the big bang - at which time everything was so weird that none of the physics-as-we-know-it works right anyway. There's a lot of hypothesizing about what happened right at the start, but thus far NSF hasn't seemed willing to fund the experiments to find out. At this point, it seems like we ought to jump over to either net.origins or net.philosophy. -- ...Cerebus for dictator! Dick Dunn {hao,ucbvax,allegra}!nbires!rcd (303) 444-5710 x3086
gwyn@brl-vgr.ARPA (Doug Gwyn ) (04/26/84)
One way to look at this matter is to consider two different views of causality: (1) Events are caused by other events (as in the example you cite); (2) Events are caused by the nature of things combined with the environment of the things. (1) is the traditional philosophy, (2) is probably closer to reality.
gwyn@brl-vgr.ARPA (Doug Gwyn ) (04/27/84)
The standard objection to Kaluza-like theories (those which add dimensions to provide internal symmetries) is that one then has to explain why four coordinates appear to uniquely identify a event. There is something upsetting in the idea of postulating higher dimensionality without being forced to..
crummer%AEROSPACE@sri-unix.UUCP (05/13/84)
From: Charlie Crummer <crummer@AEROSPACE> If "the laws of physics" don't cause anything, then what does? Maybe it's God in the guise of humans. (Holy spirit within or whatever.) We initiate events which then proceed according to the laws. --Charlie
crummer%AEROSPACE@sri-unix.UUCP (05/13/84)
From: Charlie Crummer <crummer@AEROSPACE>
Re: Gwyn's #2-- Events are caused by the nature of things combined with
the environment of the things.
Please explain how it is that the NATURE of a thing can cause anything.
An environment seems to me to comprise things.
Hey, all you atheists and closet theists, what's threatening about
distinguishing between interim causes (the dominoes) and a first cause (He who
knocks down the first dominoe). The distinction is not an explanation of
anything. Physicists aren't in danger of losing their jobs if it is found out
that God exists!
--Charliegwyn@Brl-Vld.ARPA (05/14/84)
From: Doug Gwyn (VLD/VMB) <gwyn@Brl-Vld.ARPA> I was making a distinction between things and actions, which the commonly- accepted view of causality does not (at least not in the same way). This is only one of several points of philosophy that can be quite relevant for the physical theorist, but it is not clear that an extended discussion on this mailing list would be appreciated. It is my firm belief that a fundamentally different attitude toward the "laws of physics" is taken by those who believe in a Prime Mover than by those who do not. In one case, the laws are "handed down from above" and could have been different; in the latter case, the laws cannot be arbitrary but must be the only possibility. The job of the theoretician is also different: in the first case, he is trying to discover what patterns exist and considers anything possible unless there is experimental evidence to the contrary; in the second case, he is trying to understand how the patterns are determined by a few truly fundamental principles and how those few principles can be further reduced. Even if the mathematical expression of the ultimate laws of physics were the same in both cases, it is clear that a fundamentally different mind-set holds for each of the two belief systems. The degree of certainty in the current state of one's knowledge is also affected by one's idea of what causes physical laws.
jso@edison.UUCP (05/19/84)
In reference to the "source of physical laws", I've thought of an interesting theory relating to Zeno's paradox, which "proves" that motion is impossible: to travel a unit distance requires traveling half that distance, then the other half; each half is broken down recursively, ad infinitum, so that any motion requires moving an infinite number of infinitesemal distances, taking infinite time. The solution to this paradox is easy with quantum dynamics: once the distance is below that given by the uncertainty principle, it has effectively already been taken. Zeno's paradox then *explains* motion as a number of quantum jumps. In relation to the origins of physical laws: suppose that in the initial singularity (t==0), the universe was in a "juxtaposition of states" where it had the possibility of many sets of physical laws - any of these sets that did not have quantum uncertainty or something similar would fall to Zeno's paradox, and literally never get anywhere, while the one that eventually hit p==1 when things cooled down would have to have this property. (This is probably complete nonsense, but might just have some meaning to it. Just a thought.) -John Owens uvacs!edison!jso
csc@watmath.UUCP (Computer Sci Club) (05/23/84)
Zeno's paradox is not a real paradox in the sense that we need quantization
of space to resolve it. The paradox states take any finite length. We can
divide it into an infinite number of lengths, getting smaller and smaller,
but each of finite size. To travel any finite length requires finite
time. Therefore to travel the original length requires an infinite number
of finite times, hence an infinite time. The falacy is in the last conclusion.
We have assumed that a finite length can be partitioned into an infite number
of smaller but still finite lengths. Therefore we can also assume that a
finite time can be partioned into an infinite number of smaller but still finite
times. Hence we cannot conclude that if we have an infinite number of finite
times they combine to form an infinite time.
To illustrate, assume an object moves one meter in one second. Zeno says
that to move one meter you will first have to move 1/2 meter, then 1/4 then
1/8, then 1/16 and so on. To do this will require 1/2 second, then 1/4, then
1/8, then 1/16 and so on. We do not assume that the collection of distances
combines to form an infinite distance. Hence we cannot conclude that
the collection of times combines to form an infinite time.
William Hughesgwyn@brl-vgr.ARPA (Doug Gwyn ) (05/23/84)
It does not require QM to resolve Zeno's paradox. Continuum mathematics and Newtonian physics can deal with this.
crummer%AEROSPACE@sri-unix.UUCP (05/24/84)
From: Charlie Crummer <crummer@AEROSPACE> Think about this. In The Beginning, according to the Big Bangers, the universe was tied up in a singular space-time knot. In such a situation how does the common concept of "before" make sense? Maybe "What happend before the Big Bang?" or "Who or what existed before God that created Him?" are MEANINGLESS questions. --Charlie
hsf@hlexa.UUCP (Henry Friedman) (05/25/84)
It seems that the real signficance of Zeno's Paradoxes is missed when
we take them too literally. Zeno (a disciple of Parmenides) was
really implying a spacetime continuum.
If the motion of an object is viewed as an array of events in
four-dimensional spacetime, then from a standpoint of an assumed
viewpoint beyond spacetime, the object hasn't really moved from
event to event. It was, as it were, at every point of its world
line simultaneously. Zeno and Parmenides founded the school of
Eleaticism (they lived in Elea), which held that all change (motion)
was an illusion.
Henry Friedmanjbf@ccieng5.UUCP (05/26/84)
Zeno's paradox is no problem even without quantum mechanics! The solution involves the procedure known as Integral Calculus -- you add up an infinite number of infinitesimals, and come up exactly with the finite number you have come to suspect! Thus Zeno's paradox comes down to 1/2 + 1/4 + 1/8 + .... + 1/2^(n+1) + ... = 1 ! Azhrarn -- The above is my personal opinion. In all probability, everyone else disagrees! Reachable as ....allegra![rayssd,rlgvax]!ccieng5!jbf