Subject: Re: Hermeneutics and the difficulty to count to three...
From: moggin@nando.net (moggin)
Date: 31 Oct 1996 03:35:44 GMT
matts2@ix.netcom.com (Matt Silberstein):
> > My point about Indy cars was that, at low speed, it is impossible,
> > even "theoretically" to distinguish between Classical Mechanics and
> > GR. Not they are close, not good enough for government work, not
> > approximately correct. You can't measure the difference. You can't
> > design an experiment to tell you which is right, because the
> > difference is smaller than any possible measurement error.
>
moggin:
> Wait a minute. That shows you can't _practically_ distinguish
> them.
Matt:
> > So in that domain both models explain the same data and you can't pick
> > one right and one wrong.
moggin:
> If you take Einstein as given, it follows that Newton will be off
> by some amount, no matter how small, right down the line. Now, if you
> want to begin with another premise, fine. Perhaps you want to suggest
> that the universe contains different and conflicting sets of principles,
> such that it follows Newton here and Einstein there. If _that_ was the
> given, your conclusion would follow.
stewart@Dahlquist.Stanford.EDU (Michael Stewart):
> I apologize if I've rehashed old points or if I've reached too far in
> my relatively shallow understanding of physics.
It can't be any shallower than mine. Maybe this would be a good
time for me to reiterate that my knowledge of the subject is strictly
limited. Note to Ted -- I don't know much about auto racing, either.
> I think the point is that Einstein isn't given.
Fine. That's why I said "if," and why I've been at pains since
the beginning of this conversation to make it plain what premises I
was speaking from. Change the premises, and naturally you'll arrive
at different conclusions.
> They are both
> theories which draw credibility through their ability to explain
> observations. There is a signficant range over which we are not able
> to determine experimentally that Einstein is more accurate than
> Newton. We don't really know that Newton isn't exactly right under
> such circumstances.
That depends on what you mean by "really know." You seem to be
using it as a synonym for "determine experimentally." But that means
you're just saying, "We can't determine experimentally what we can't
determine experimentally." I wager that's so.
> This is probably why many people are annoyed when hearing Newton's
> theory declared to be wrong: such a declaration is either based on the
> notion that a theory is right only if it is universally applicable (in
> which case no physical theory is ever likely to be right) or it is
> based on the assumption that we know Newton's theories to be at best
> an approximation in all circumstances (which hasn't been
> experimentally verified).
Taking Einstein as given (if you don't want to, then don't), it
follows that Newton produces a range of errors from small to large:
surely a bad sign for any scientific theory. I thought that was well-
accepted by now, but it seems that some people find it quite annoying
to hear. The reason for that remains to be fully determined. Can't
say as I find your explanation too persuasive, though.
> The notion that Newtonian mechanics is only
> approximately correct over the range in which it is commonly used is
> based on an unjustifiable extrapolation which assumes that relativity
> is more accurate at low velocities merely because it is more accurate
> at high velocities.
It's not unjustifiable in the least, although you may reject the
reasoning. The extrapolation (or interpolation, I'd think) accepts as
a premise that natural laws function consistently -- which is to say
that the universe doesn't switch horses in midstream. You're welcome
to think differently, but that puts you in the position of claiming it
operates on one set of principles over _here_, and another one over
_there_. At some velocity, you're saying, the universe switches from
Newton to Einstein, and back again going the other way. So whether
God is playing craps or anything else, he's playing by two different
sets of rules, depending on where he happens to be (or rather, on how
fast he's going). That's not impossible -- but it's an assumption
you can't do without.
-- moggin
Subject: Re: faster than light travel
From: jwas@ix.netcom.com(jw)
Date: 31 Oct 1996 04:16:02 GMT
In <01bbc62c$da817b00$7ec4abcf@default> "Kevin Thomas"
writes:
>
>The "grandfather paradoxes" are actaully just erros of logic. There
really
>is no paradox when the logic errors are weeded out. As Kip Thorn
pointed
>out, if you are planning to go back in time tomorrow to kill you
>grandfather 50 years ago, although you haven't experience the journey
yet
>yourself, as far as the universe is concerned, you have already
completed
>you actions in the past. So although you yourself do not know what is
>going to happen when you get into the past, you may infer by the fact
that
>you are alive, as well as your grandfather, that for some reason on
your
>journey to the past you fail to kill him.
>
>The logic error is putting "cause" before "effect" in a journey to the
>past. In this situation, "effect" comes before "cause". In other
words,
>you actions have already been carried out before your decision to
perform
>them. So in the so-called "grandfather paradox" you know that
regardless
>of your intentions to kill your grandfather, for whatever reason, you
will
>fail to do so in your journey to the past.
This hardly resolves the paradox.
For every thought experiment of changing retroactively
anything at all that is already on record - an unexplained
new factor, different in each case - "for whatever reason" - is
introduced to prevent the paradoxical result.
This is not good enough.
It begs the question. We already know that the
past can't be changed - because then the present
would be different - the question is *why*? For a special,
accidental, unknown reason in each case,
a *deus ex machina*? Or - a much neater explanation - because
a general, formal, analytical law of nature prohibits causality
to propagate from the present to the past? Occam's razor selects
the latter explanation, if it is possible.
In decent classical cases, it is: we have such a law:
the light speed limit. Cases involving singularities
(like wormholes) need to be
elaborated; but the end result, when and if the
theory is complete, must again be non-paradoxical
for any thought experiment - i.e. it must forbid
sending a signal to the past to change it -
in particular, forbid time travel.
Is there a natural, not *ad hoc* way, to
introduce such a prohibition? Apparently yes.
To quote from Kip Thorne's book
_Black Holes & Time Warps_, Chapter 14:
||"Hawking has a firm opinion on time machines.
||He thinks that nature abhors them, [...]
||Hawking suspects that the growing beam of vacuum
||fluctuations is nature's way of enforcing
||chronology protection: *Whenever one tries
||to make a time machine, and no matter what
||kind of device one uses in one's attempt
||(a wormhole, a spinning cylinder, a "cosmic
||string", or whatever), just before one's
||device becomes a time machine, a beam of
||vacuum fluctuations will circulate through
||the device and destroy it.*
||Hawking seems ready to bet heavily on this
||outcome.
||I am *not* willing to take the other side in
||such a bet. [...] My strong gut feeling is
||that I would lose this one. My own calculations
||with Kim, and unpublished calculations that
||Eanna Flanagan (a student of mine) has done
||more recently, suggest to me that Hawking is
||likely to be right. However, we cannot know
||for sure until physicists have fathomed in depth
||the laws of quantum gravity."
Subject: Re: what Newton thought
From: mls@panix.com (Michael L. Siemon)
Date: Wed, 30 Oct 1996 22:56:36 -0500
In article <5549ao$7uv@ssbunews.ih.lucent.com>, lew@ihgp167e.ih.att.com
(-Mammel,L.H.) wrote:
+Mach and Einstein both discuss the Newtonian conception.
+Cf. Appendix Five of Einstein's popularization, Relativity:
Much as I respect Einstein (as physicist) and Mach (as philosopher
of science, though somewhat less than my respect towards Einstein, to
be sure! :-), neither one strikes me as particularly cogent about the
history of physics, or the analysis of Newton *in his own terms*.
+I cite the Scholium on Definitions, of course. There is
+also reference in The System of the World to "the fixed stars
+being at rest" ( Phenomenom IV ) and in addition:
But these are precisely the data which buttress my assertion.
Let's take this moderately slowly:
+ Hypothesis I
+
+ That the centre of the system of the world is immovable.
+
+ This is acknowledged by all, while some contend that the
+ earth, others that the sun, is fixed in that centre. ...
This would be more compelling if you showed some familiarity with its
context. What Newton is *in fact* doing here is demonstrating that the
old argument of heliocentrism versus geocentrism is misconceived and
that neither position is correct (i.e., neither the earth nor the sun
is immovably central.) Your ellipsis is crucial to Newton's use of
this Hypothesis. Let me replace what you have edited out:
"... Let us see what may from hence follow.
Proposition XI. Theorem XI
That the common centre of gravity of the earth, the sun, and all
the planets, is immovable.
For (by Cor. IV of the Laws) that centre is at rest, or moves
uniformly forwards in a right line; but if that centre moved,
the centre of the world would move also, against the Hypothesis."
Now this is curious. There are scattered remarks in the scholia which show
Newton to be alive to the possibility of gravitational influence from the
stars on the planetary system, so he is (I must infer) alive to this being
something of a false dichotomy -- that centre *could* be accelerating under
stellar influence. All he *really* manages here is to undercut any claim
that earth or sun *are* absolutely fixed. And what is weird is that this is
one of only two hypotheses in the Principia (the other is a quite technical
one, possibly a theorem he couldn't quite prove to his own satisfaction,
but wanted to use in his discussion of precession.) His "background" to
Hypothesis I is equally peculiar, and radically different from anything
else in the book -- "acknowledged by all" -- without a trace of argument
by Newton. Maybe he *did* believe that center of gravity of the solar system
was the absolute center of absolute space. I'd really hate to argue that
point from *this* text! (And yes, what I am doing here bears some resemblance
to what I regard as legitimate usage of deconstruction. So sue me.) From
the standpoint of the PHYSICS, the whole of Hypothesis I and Props. XI and
XII is the observation that the solar system is either absolutely at rest,
or in uniform inertial motion (barring other forces acting than the planet-
ary gravitational interactions.) This is part of what I mean by saying
that Newton *hints* at a belief in absolute space and motion, but does so
in a manner that, in practice, denies any substance to such a notion.
Now, let's look at the general scholium on definitions that is your other
claim against my assertion.
+>................... I suspect that I can quote _Principia_ to
+>undermine any very plausible absolutism you might attempt to
+>extract from it.
+
+I'm flabbergasted by this. Go ahead!
You asked.
"All things are placed in time as to order of succession; and
in space as to order of situation. It is from their essence or
nature that they are places; and that the primary places of
things should be movable, is absurd. [NOTE: no argument here --
this amounts to a bald prejudice, but I certainly take this as
one of the hints I mentioned as to Newton's own beliefs.] These
are therefore the absolute places; and translations out of those
places, are the only absolute motions.
You could claim victory *if* this were all that Newton wrote, but he
goes on, immediately, to say:
"But because the parts of space cannot be seen, or distinguished
from one another by our senses, therefore in their stead we use
sensible measures of them. For from the positions and distances
of things from any body considered as immovable, we define all
places;"
[please note that bit about our use of "sensible measures"
and positions from a body "considered as immovable" :-)]
"and then with respect to such places, we estimate all
motions, considering bodies as transferred from some of those places
into others. And so, instead of absolute places and motions, we use
relative ones; and that without any inconvenience in common affairs;
but in philosophical disquisitions, we ought to abstract from our
senses, and consdier things themselves, distinct from what are only
sensible measures of them. For it may be that there is no body really
at rest, to which the motions of others may be referred."
This amounts to saying that absolute motion is a philosophical fiction, you
know. It gets worse:
"But we may distinguish rest and motion, absolute and relative, one
from the other by their properties, causes, and effects... it follows
[from *possible* considerations of fixed stars at absolute rest] that
absolute rest cannot be determined from the position of bodies in our
regions."
There is a half-hearted attempt to use central accelerations as examples of
such "causes and effects" -- this is the point on which Mach notes that we
in fact *have* no such demonstration: any effects may be attributed to the
action of other forces, or the equivalence of gravitational and dynamic
effects.
I could go on; a bit later he writes:
"Wherefore, entire and absolute motions can be no otherwise deter-
mined than by immovable places; and for that reason I did before
refer those absolute motions to immovable places, but relative ones
to movable places."
This simply admits that NO measured motion, and no physics, rests in any
way on reference to an absolute spacetime. The _Principia_ (its entire body
after the definitions) makes no use of "absolute" space or time, except in
the peculiar Hypothesis I, which has a much more limited context than you
wish to urge on it.
Newton's *prejudice* is clear. His physics explicitly procedes without use
of that prejudice, and I really do *not* know what his "real" opinion was.
Mach (and following him, Einstein) showed what a reading of Newton entailed
that did not get hung up on the irrelevant prejudices.
I am *not* arguing that Newton "was" a relativist -- the data suggest, but
do not prove, otherwise. I *do* assert that Newton himself writes a text
that makes absolutist notions *irrelevant* to physics. It may have taken
200 years for that point to sink home, but I cannot see how anyone with the
slightest respect for Derridan methods *and* for physical theory can dispute
the claim.
--
Michael L. Siemon mls@panix.com
"sempiternal, though sodden towards sundown."
Subject: Re: "Essential" reality (was: When did Nietzsche wimp out?)
From: lbsys@aol.com (LBsys)
Date: 30 Oct 1996 23:00:12 -0500
Im Artikel , meron@cars3.uchicago.edu
schreibt:
> The theory that predicted decay, predicted also a specific
> decay mode. So you know, in principle, what you're looking
> for and what is the chance to miss it if it happens. But, true,
> the theory may be completely off in which case you're indeed
> looking in the wrong direction. Unfortunately it is impossible
> to set an experiment based just on "lets see if anything happens",
> you've to have at least some prediction regarding what is it
>you're looking for.
Oh, I don't doubt that even for getting only some measly dollars to
finance any sort of project, one should have a decent theory and a
prediction based on it. The problem, unfortunately, stays with us b/c of a
very basic logical problem, which was 'discovered' when inventing 'error
trees'(?), i.e. models of failures and their resp. probability. It is in
fact in the same class as stated in Uncle Al's sig: "quis custodiet...",
or the typical teachers mistake: "Anyone missing, please raise their
hands", in this case: how can I ever prove, I didn't forget to take a
major point into account, a strange combination etc... The TWA800 *may*
have been such a case: the last news I've seen about it, was, that the
crash has been caused by an _exploding_ fuel pump - who'd ever thought of
that? In s/w engineering it happens all day long. A friend in the US just
installed NT4.0 on his brandnew home PC. So he went up through the setup
and when being asked for UserID and Password just left it empty, as he
didn't want to be bothered with a PW-check every day. NT accepted this
choice, but when rebooting wouldn't let him in - no PW given. He had to
blank the disk completely and start anew. Of course the designers of NT
hadn't thought of an unsecured system at all, quite the opposite, and
didn't dream of a user not to specify a PW. :-(((
Cheerio
The most dangerous untruths are truths slightly deformed.
Lichtenberg, Sudelbuecher
__________________________________
Lorenz Borsche
Per the FCA: this eMail adress is not to
be added to any commercial mailing list.
Uncalled for eMail maybe treated as public.
Subject: Re: Constancy of the Speed of Light--Purely Mathematical?
From: bjon@ix.netcom.com (Brian Jones)
Date: Thu, 31 Oct 1996 03:49:24 GMT
Christopher R Volpe wrote[in part]:
>Brian D. Jones wrote:
>In the following line, bjon admits that absolute motion has not been
>detected.:
>> >> all I am saying is that it has not been done,
>I'll come back to this later. Now on to facts versus theories:
>> >> leaving open the possibility, however slight, that it may be done in
>> >> the future. In fact, this "open-end" view is necessary if SRT is to
>> >> be a testable (i.e., scientific) theory.
>>
>> >BS. Is the "open end" of possibly discovering the world's flatness
>> >someday necesssary if the round-earth theory is to be a testable
>> >scientific theory?
>>
>> There's a very small but critical distinction between a fact and a
>> theory.
>> >>
>What bjon fails to understand is that facts are observations and
>theories are explanations for them. Theories do not become facts.
>"Theory" is not a stepping-stone to fact-hood.
I have no idea why Volpe said this, but I am trying to get across the
following: We have an observation that the earth is round, so this
statement is a fact. SRT, OTOH, is a theory.
>> >> And the main point I was trying to make was about absolute motion
>> >> itself having existence. To say that absolute motion does exist is not
>> >> the same as saying we have not detected it yet.
>>
>> >True, but it IS the same thing as saying that it can never be detected,
>> >even in principle.
>>
>> Essentially, it's detected everyday.
>Bjon just got through saying that absolute motion has not been detected,
>and now he says it is detected every day. Since this is apparently all
>SR says can't be done, one wonders why bjon has not yet received the
>nobel prize for his disproof of SR.
There's no contradiction, as my later sentence revealed.
>> It's the only thing that
>> distinguishes one observer from another.
>No, that would be called "relative motion".
Mere relative motion cannot make any such real distinction.
And observers really differ, as their different observations show.
>> But, of course it's not the detection that is important, it's the
>> determination of one's absolute velocity.
>When one speaks of "detecting absolute velocity", what one usually means
>is the determining of one's absolute velocity in general, or
>distinguishing it from zero in particular. Demonstrating that
>alpha-centauri is receding from is *not* a detection of absolute motion,
>but rather of the relative motion between it and us.
True, but irrelevant.
>> >There is no difference between existence and the ability to be detected.
>> >The ability to be detected, in principle (even if technologically it is
>> >not currently possible), is the very essence of "existence".
>>
>> See above.
>Gee, I did, but there's nothing bjon has said that addresses this point.
>All he did was point to relative motion, and mis-label it absolute
>motion.
See new above.
>> >> And of course one can say that this is
>> >> "good enough" for physicists to "deny its very existence," but by so
>> >> doing they deny the very testability of SRT itself.
>>
>> >Does denying the existence of "absolute up" deny the testability of the
>> >round earth theory?
>>
>> Facts don't need testing, only theories.
>I could grant bjon that the roundness of the earth is a fact, but that
>would be beside the point. Getting back to his erroneous claim: Bjon has
>stated time and time again that SR must be *FALSE* in order to be
>*FALSIFIABLE*.
This would be plain silly, and I have never said such a thing. All I
have ever said is that (as is well known) every scientific theory must
be falsifiable, and I have tried to contrast this rule with the many
claims of some relativists that SRT is fact or fully verified or
confirmed, etc. I have often compared SRT to the old theory that "Man
shall never fly." This cannot be proved, but can be disproved, making
it falsifiable and therefore a legit theory. Many act as though SRT
has been totally verified, which would make it a "fact," which it
can't be because it's a negative statement.
That is, SR's mere assertion that there is no way to
>detect absolute motion makes itself unscientific.
You have missed the point, although it was a pretty simple one.
I was simply saying that since SRT says "No absolute motion
detection," then such motion must exist or else SRT would not be a
testable theory, as it must be to be scientific. This is because the
only way to test it is to search for a way to detect abs motion, and
this means that such motion must exist.
>Completely bogus. SR
>provides for many ways in which it can be disproven. In fact, its
>assertion that there is no way to detect absolute motion provides for
>its falsifiability. All you have to do is detect it. Go ahead and detect
>absolute motion, and you've disproven SR. SR is very falsifiable. It
>just hasn't been falsified. Given the number of ways and number of times
>it has been tried, a reasonable person might conclude that the reason
>for the failure to falsify it is that it is an accurate description of
>reality in the realm it was designed to describe.
This is true. But we must not mislead folks by stating flatly that
SRT has had many "verifications," as is done often. It cannot be
verified because of its negative nature, just as the above "No one
shall ever fly" theory was unverifiable.
>A good analogy is Thermodynamics's claim that it is impossible to build
>a perpetuual motion machine. I suppose bjon thinks that the laws of
>thermodynamics are unfalsifiable, and hence unscientific, because of the
>inability to find a perpetuual motion machine. Most, if not all,
>scientifically literate people would agree that the claim of the
>impossibility to build a PMM itself demonstrates falsifiability. In
>order to demonstrate falsifiability of a claim, one must merely be able
>to anwser the following question in the affirmative: "Is there anything
>I can do or observe that will demonstrate the falseness of the claim
>under consideration?" With thermodynamics, the answer is obviously yes:
>Build a device that outputs as much or more energy than it consumes.
>With SR the answer is also obviously yes: Conduct an actual experiment
>whose outcome depends on the inertial frame in which it is carried out,
>without any "outside" information coming in from other identifiable
>frames. No one but bjon claims that SR is not falsifiable.
As I explained above, this was not my claim at all, but I was trying
to show how SRT's falsifiability implies the existence of absolute
motion (not it's detection, though).
I really don't see how Volpe could have twisted this around so badly.
>At this point I would like to point out that so far bjon has held three
>mutually inconsistent positions regarding SR:
>1) The conditions of SR's disproof (detection of absolute motion) have
>not been met. (See the very top of this post).
True as rain water.
>2) The conditions of SR's disproof are met every day. (Roughly 35 lines
>down from top of post.)
Twisted as a hog's tail.
>3) The conditions of SR's disproof do not exist because SR is not
>falsifiable and not scientific. (Preceding discussion)
Ditto.
>> >Does denying the existence of perpetuual motion machines also deny the
>> >testability of the laws of thermodynamics?
>>
>> Yes.
>I'm glad Bjon admits it. At least he is consistent, even if consistently
>wrong.
>Again, in order for Claim X to be falsifiable, there must merely be a
>set of identifiable circumstances that would constitute disproof of
>Claim X. When Claim X is something like "it is impossible to build a
>perpetuual motion machine", or "there is no way to distinguish any
>inertial frame from being at absolute rest", the identifiable
>circumstances of falsifiability are self evident. When Claim X is of the
>form "there exists an inertial frame which is absolutely at rest, and in
>this frame only are E-synched clocks 'truly synched', even if there is
>no way to distinguish this frame", the circumstances which would
>disprove the claim are much more difficult, if not impossible, to
>identify.
>>
>> >Why? I claim that there is a "real" up direction, and that a plane
>> >perpendicular to this direction is "really horizontal". It's as
>> >meaningful a claim as your claim regarding absolutely-synched clocks
>> >being able to identify the absolute rest frame.
>>
>> Because an "up" has no possible existence, being a mere concept.
>Says who? I could just as easily claim that "absolute rest" has no
>possible existence, being a mere concept.
"Up" is purely a relative notion, as everyone knows. But the situation
with absolute motion is entirely different. [1] Absolute motion must
exist if SRT is to be falsifiable (since SRT claims that we cannot
detect such motion). [2] If two observers move relative to each other,
then at least one of them must be actually (or absolutely) moving
through space. [3] The only possible cause for two observers finding
different time intervals for two given events is a difference in the
observers' absolute velocities. [4] Anything that exists must either
be at absolute rest in space or moving absolutely through it, as any
other view is inconceivable.
>> CLocks are real instruments, and can actually be truly set, if only by
>> sheer accident.
>Arrows are real pointy things, and can actually be truly pointing up, if
>only by sheer accident.
If only "UP" had any real meaning.
Everyone knows that true synch has a real meaning (except Volpe).
>> >> And even though true clock synch is equivalent to
>> >> the concept of absolute motion,
>>
>> >I'm holding you to this admission. When I quote you in the future, don't
>> >deny you said this.
>>
>> Of course it is, as I have said all along. But this is no fantastic
>> secret as you seem to think.
>Fair enough. Then you admit that it is of no consequence to claim that
>you can detect absolute motion by using a pair of truly synched clocks,
>just as it is of no consequence to claim that you could detect unicorns
>if you had a unicorn-detector.
If only "Unicorns" were real.
>>
>> >>it does make for a clear example to
>> >> help get across the point that absolute motion has an existence
>> >> because one can see that it is physically possible for two clocks to
>> >> be truly synch'd,
>>
>> >Non-sequitur. Absolute up has an existence because one can see that it
>> >is physically possible for a plane to be truly horizontal.
>>
If only "truly horizontal" had any meaning.
>> It is not possible because truly horizontal itself has no existence.
>Proof by blatant assertion. Of course, I really do in fact agree that
>"truly horizontal" has no existance, but the point is that "truly
>horizontal" has as much existance as "truly synched" or "truly at rest".
>They are all the same thing: "Up", "At rest", and "In synch" are all
>relative concepts. "Up" depends on where you are on earth, and the other
>two depend on what inertial frame you are in. It's that simple. But if
>you want to claim that it is possible for two clocks to be truly
>synched, I will continue to make the equivalent claim that it is
>possible for a plane to be truly horizontal.
Not equivalent at all. Clocks do exist, and have hands which can have
any number of real positions on their dials. All I am saying is that
it is physically possible for these hands to match for a pair of
clocks, if only by accident, or if monkeys adjusted them.
>>
>> >> >Detectableness is equivalent to existence, as far as physics is
>> >> >concerned. Einstein was pretty clear about that.
>> >>
>> >> They'd better not be precisely equivalent, or his own theory becomes
>> >> untestable.
>>
>> >Non-sequitur. In no way does the use of the word "existence" to mean
>> >"detectability in principle" make the specific quantitative claims of SR
>> >untestable.
>No response to the above claim?
See my above.
>>
>> SRT makes only one (1) claim, and this single claim must be testable
>> if SRT is to be an acceptable theory,
>SRT makes two claims, each one expressed in the form of a postulate.
>The first claim is the principle of relativity (PR). It says that all
>inertial frames are completely equivalent for purposes of expressing
>the laws of physics in a quantitative way. It is another way of saying
>that it is impossible to distinguish one frame from another based on the
>way in which physical processes transpire. This implies the
>impossibility of distinguishing "absolute rest" from "absolute motion".
>It is falsifiable merely by doing what is claimed can't be done: Conduct
>an experiment entirely within an inertial frame, without using any
>information regarding that frame's motion relative to some other
>identifiable frame, that demonstrates that physical processes behave
>differently in different inertial frames.
So SRT cannot have been fully verified if it is falsifiable. And there
cannot have been any experimental results or facts (such as time
dilation) that have "confirmed" SRT beyond doubt. This was my point.
>The second postulate is called the law of propagation of light (LPL). It
>says that, given an observer at rest in some arbitrary inertial frame,
>and two light sources moving with different, and arbitrary, velocities
>in that inertial frame, light emitted by each of the two sources at the
>same place and time will be emitted with the same speed, and that the
>observer will therefore note that the two light waves are
>"co-travelling" with each other in all directions, with arrivals at any
>given target coinciding.
Einstein never said it like that. All he said was that light's has a
constant speed thru space due to its source independency. Of course,
the above means the same, but why make it so confusing? And note that
unless the two sources have different real (absolute) speeds, your
whole statement is meaningless because a mere difference in merely
relative speeds could have no real result anyway, so you would not
expect to see any difference in the first place.
>These are the two claims of special relativity. The second one is
>confirmed over and over again by experiment. Bjon likes to call this
>second postulate "fact". In actuality, it is a claim that is consistent
>with a finite number of experiments, just like the first postulate, and
>is subject to later disproof, just like the first postulate.
As I have mentioned often, this Axiom was verified experimentally in
1977 by Ken Brecher. (Actually, Brecher verified light's source
independency speedwise, which means that light has no reason to vary
its absolute speed in space.) This axiom is no longer subject to
disproof, nor need it be, as is the case for SRT.
>Bjon likes to claim that the first postulate is all that SR claims. This
>is of course false, since Newton also claimed the PR was true, but
>Newtonian relativity is quantitatively different, i.e. makes different
>predictions, from Einsteinian relativity.
As I have said many, many times (but you insist on conveniently
overlooking just to have something to say and to argue about),
Newton's View differed in that he did not consider optical experiments
as being automatic failures. And while I am at it, I may as well say
that the First Axiom (as I have also said repeatedly) is not really
SRT itself. All the 1st Axiom says is "Same laws." It says nothing
about detecting absolute motion, as does SRT.
>--
>Chris Volpe Phone: (518) 387-7766
>GE Corporate R&D; Fax: (518) 387-6560
>PO Box 8 Email: volpecr@crd.ge.com
>Schenectady, NY 12301 Web: http://www.crd.ge.com/~volpecr
>>BJ<<
**bjon@ix.netcom.com**
Subject: Re: [Fwd: Re: The Conscious Mind -- David Chalmers]
From: andersw+@pitt.edu (Anders N Weinstein)
Date: 31 Oct 1996 05:14:26 GMT
In article , Jim Balter wrote:
>In article <558rl3$44n@usenet.srv.cis.pitt.edu>,
>Anders N Weinstein wrote:
>>as for matter that constitutes non-tables. So the physical laws as it
>>were don't care about the difference between tables and non-tables -- even
>>if it is a real one. Ditto for living and non-living things.
>
>So in your view biology either doesn't care about the difference between
>living and non-living things or doesn't involve "the physical stance"?
Of course it cares about the difference. No it does not just use the
physical stance, it has its own explanatory principles.
"Involves" is a problem here -- of course it "involves" the physical
stance in that it makes free use of physics where relevant -- so does
Gibson, so does the computational level. However much of biology makes
use of the teleological form of explanation, which itself is no part of
explanation according to the physical stance.
>To me, the "physical stance" is one from which we can describe human organisms
>via models using lower level terms. We can also describe human activities,
I think I agree.
>such as language use, in terms of our models of human organisms. And we can
>describe the interrelationships between various language uses in terms of our
>models of language. When someone says she loves her mother, I want to be able
>to discuss this in terms of human meanings, emotions, social relationships,
>brain structure, and the like. Each of those can in turn be discussed in
>lower level terms. Meaning is particularly tricky because it is somewhat
>recursive in and of itself and because it is recursive in a deeper sense that
>we use language to create our models and discuss meanings; those who have
>programmed complicated recursive functions know how difficult it can be to
>carve things up just right so that a function can be defined in terms of
>itself. Or how confusing it can be to think about bootstrapped cross
>compilation systems where programs are implemented by variants of themselves.
>But that doesn't mean that we should just throw up our hands at some point and
>declare something "irreducible".
I don't think recursion is the main source of the irreduciblity. The
problem is mainly that meaning (like function) is a normative notion,
and the world as explained via the physical stance is norm-free. So
you can't get from the laws of physics to the norms of rationality.
Perhaps the problem of reflexivity is also genuine -- we have to use a
language all the while we theorize about it. So we don't really have a
vantage point from which to talk about, e.g, the imposition of
boundaries on an unconceptualized reality. The only world that could
be an object for us is conceptual.
>>But the physical account might be complete as it stands. The physical
>>account of tables is complete, yet does not mention tablehood.
>
>But a physical account of a human uttering the word "table"? "Tablehood" is a
>human concept; when that is the target rather than merely the composition of
>tables, then the physical(ist) study of humans and their activities must enter
>in. The problem here, as so often, is a confusion of levels and categories.
Agree "tablehood" is a human concept. However, I believe the irreducibility
applies at both ends -- physical science does not explain what a table is,
but also what a person calling something a table is doing. The latter
act is also norm-laden -- it is something that can be correct and incorrect,
and involves something like following a system of *rules*, not merely
emitting a noise.
>>>become an eliminativist. Given these options, I choose the latter - for
>>>the former inevitably puts an end to reasoned discussion and progress.
>>
>>I have embraced metaphysics long ago.
>
>Thereby putting an end to your progress.
True enough.
Subject: Re: what Newton thought
From: mls@panix.com (Michael L. Siemon)
Date: Thu, 31 Oct 1996 00:11:00 -0500
I observe that I failed to deal with one of Mr. Mammel's citations:
+In article <5549ao$7uv@ssbunews.ih.lucent.com>, lew@ihgp167e.ih.att.com
+(-Mammel,L.H.) wrote:
++There is
++also reference in The System of the World to "the fixed stars
++being at rest" ( Phenomenom IV )
Unfortunately for Mr. Mammel, this does *not* in any way aid his
case, as it neither argues for nor relies on the fixed stars being
absolutely at rest. Rather, it deals with Kepler's third law -- the
periods of the planets being "as the 3/2-th power of their mean
distances from the sun" -- where he is taking "the periodic times
with respect to the fixed [_soi disant_!] stars."
My previous quotation from the general scholium on definitions more
than adequately shows that THIS reference is, of necessity, one of
*relative* motion. Mr. Mammel would do well to avoid confusing the
idiom "fixed stars" with a philosophical claim that these referential
bodies *are* at absolute rest. As Newton observes, "there may be some
body absolutely at rest; but [this is] impossible to know."
As I mentioned before, Newton drops hints of mutual stellar gravity
perturbing the simple view he normally adopts for his "popular" treat-
ments in the scholia. E.g., in the General Scholium to the Book III
System of the World, he observes:
"And if the fixed stars are the centres of other like systems,
these, being formed by the like wise counsel, must be all subject
to the dominion of One; ... and lest the systems of the fixed
stars should, by their gravity, fall on each other, he hath
placed those systems at immense distances from one another."
So -- prejudices of non-interaction, with explicit acknowledgement that
*if* these are material bodies, they WILL interact gravitationally.
It is worth quoting in full the famous _hypotheses non fingere_ bit:
"Gravitation towards the sun is made up out of the gravitations
towards the several particles of which the body of the sun is
composed; and in receding from the sun decreases accurately as
the inverse square of the distances as far as the orbit of
Saturn [and who can suppose that Newton thought this more than
the *measured* extent of the scope of gravity?] as evidently
appears from the quiescence of the aphelion of the planets; nay,
and even the remotest aphelion of the comets, if those aphelions
are also quiescent. [Again, Newton admits that his scheme extends
*indefinitely* beyond the solar system!] But hitherto, I have not
been able to discover the cuase of those properties of gravity
from phenomena, and I frame no hypotheses; for whatever is not
deduced from the phenomena is to be called an hypothesis; and
hypotheses, whether metaphysical or physical, whether of occult
qualities or mechanical, have no place in experimental philosophy.
... And to us it is enough that gravity does really exist [Hah!].
and act according to the laws which we have explained, and abund-
antly serves to account for all the motions of the celestial bodies.
and of our sea."
--
Michael L. Siemon mls@panix.com
"sempiternal, though sodden towards sundown."
Subject: Re: Science, Values and good old-fashioned essentialism
From: pritchjm@muss.cis.McMaster.CA (J.M. Pritchard)
Date: 30 Oct 1996 18:35:51 -0500
In article ,
Adam Hibbert wrote:
>In article <54k6n2$5ga@muss.CIS.McMaster.CA>,
>pritchjm@muss.cis.McMaster.CA (J.M. Pritchard) wrote:
>> Obviously, it is stupid to talk of an external reality in this
>> case. The "absolute" fact-of-the-matter about whether one should stop
>> or go at a red light can only be a matter of the sheerest indifference.
>> The only thing which matters is what everyone else is doing, and what
>> behaviors you will have to emulate in order to survive/and not be
>> institutionalized.
>> Evolutionarily speaking, the "false" gets weeded out because it is
>> insufficiently adapted to a dangerous environment. Our environment *is*
>> dangerous.
>Hang on a mo. What can be referred to here as dangerous? Is it *really*
>dangerous, or does it just /pass/ for dangerous? If it is really
>dangerous, we can presumably be more or less safe in it (ie, approximate
>towards it). Evolution does this slowly, language/ experience/ memory a
>lot faster.
What I want to say is that distinctions like the ones we
putatively make between "real" and "apparent" (dangers, or what have you)
are no longer objectively valid given our historical understanding.
In this sense, "danger" merely points to the more or less objective
fact that some things do indeed die, and others live. Some are happy,
others are not. Some are beautiful, and others ugly. Now there's nothing
especially analytic about any of this, that's just the way things are.
Similarly, all these things: death, unhappiness, ugliness, etc. can be
understood as "dangers" if you choose.
Now this is all in response to your first question. The next one
I'm not sure I understand. And as regards evolution, I am proposing that
we explode this notion *into* those other fields you mentioned,
especially language. Questions about the "long-term" notwithstanding, it
seems a natural move to make - no pun intended.
>> Wittgenstein does not deny that the world exists. He
>> just denies that language has a particular relation to it. The
>> constraints of living successfully are constraints enough.
>Surely those constraints determine (within reason) how we conceptualise
>the world? In fact, don't we conceptualise the world *in order that* we
>can better employ it to our advantage? We establish, in the first instance
>perhaps by convention, that a particular word refers to a particular
>object/event/quality; we end up with stuff like numbers, which give math .
>. . which reveal aspects of the world previously unappreciated . . .
>Why do i feel like I'm walking into a trap here?
Wittgenstein said that philosophy was the attempt to show the fly
the way out of the fly-bottle. Not sure if you're walking into a trap
unless it is stepping out of a smaller and into a larger one. But you're
exactly right. The "trap" is that we have lost "objective" reality - the
joke is that we never "had" it. There is no ethos, there is only pathos,
only language constantly feeding back upon itself. At least that is what
the postmodern philosophers will tell you, the ones who have erased the
boundaries between poetry and philosophy, people like Rorty, Derrida,
Foucault, etc.
But I'm starting to froth at the mouth. All this bears some more
thought, obviously - especially the criticism that we may have gained a
neat new way of talking, but have lost the "world". I don't believe that
this is necessarily the case, but this is a problem I am struggling with
as well, it is perhaps a new "danger"...
Could you repeat the question?
Jeff