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Mike11

Speed of Light?

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of different interactions possible with zillions of different effects. We can only get a grip on all those possibilities by creating a model of those interactions, in which we could pinpoint cause and effect relations if we wanted, but that is seldom the highest priority of the scientist, they are inherent in the model itself.

The situation wherein we comprehend the cause-effect relation primarily in terms of the model (or theory) for the causation is the latter day descendant of Aristotle's -formal cause-. The temporal sequence you described is the modern expression of Aristotle's material and efficient causes. Telos or final cause shows up in biology when certain processes are described as functions. For example, the heart operates in order that blood may be pumped to various parts of the body to nourish them. This statement X for the sake of Y, X in order that Y is how Aristotle's Final Cause shows up in modern scientific discourse.

There is an old saying: Le plus ca change, le plus la meme chose (the more it changes the more it stays the same). Twenty three hundred years have passed, yet some Aristotelean notions still haunt the attic of scientific theory. Aristotle hit on some basic memes which we still carry around in our heads.

Ba'al Chatzaf

Edited by BaalChatzaf

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OK, Shayne, you're playing "I asked first," but the initial statement you made described DF's terminology as "pseudo-scientific" (see). It's a loaded description, and thus expecting a reply is like expecting a reply to the "Have you quit beating your wife?" type of query.

Daniel's question, on the other hand, is legit.: Why did you call DF's terminology "pseudo-scientific"? What's "pseudo" about the terminology?

Ellen

___

Edited by Ellen Stuttle

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OK, Shayne, you're playing "I asked first," but the initial statement you made described DF's terminology as "pseudo-scientific" (see). It's a loaded description, and thus expecting a reply is like expecting a reply to the "Have you quit beating your wife?" type of query.

Daniel's question, on the other hand, is legit.: Why did you call DF's terminology "pseudo-scientific"? What's "pseudo" about the terminology?

Ellen

___

Not a thing. DF was rather careful in his statement. Our buddy Shayne apparently takes the position that if he cannot understand something, then that something is nonsense. Or so it would seem.

Ba'al Chatzaf

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OK, Shayne, you're playing "I asked first," but the initial statement you made described DF's terminology as "pseudo-scientific" (see). It's a loaded description, and thus expecting a reply is like expecting a reply to the "Have you quit beating your wife?" type of query.

Daniel's question, on the other hand, is legit.: Why did you call DF's terminology "pseudo-scientific"? What's "pseudo" about the terminology?

Ellen

You and Daniel are the ones playing games and being illogical. My question is trivial: Translate a simple everyday statement into the jargon. I asked for that when the question first came up. And doing that translation would answer Daniel. If the jargon can't support conveying such a simple statement, then it is clearly pseudo-scientific, muddying the waters to make them appear deep.

Daniel and you are merely objecting that I called it "pseudo-scientific" without saying why. Yes, it was a taunt, a dare for Dragonfly to show otherwise, because I really don't think that he can. You two are being like little children who don't understand what Daddy Dragonfly said but are supporting him anyway. I'd repeat to you what I did to Daniel that you're not qualified to be asking me questions or making corrections, you don't even comprehend what Daddy said.

Shayne

Edited by sjw

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Not a thing. DF was rather careful in his statement. Our buddy Shayne apparently takes the position that if he cannot understand something, then that something is nonsense. Or so it would seem.

Ba'al Chatzaf

No, I take the position that if you can't take a simple everyday statement and express it in your proposed terminology, then the terminology is BS. I didn't even try to understand DF's statement, it smelled of BS, and the onus is on him to give meaning to his proposal, so I did part of his work for him and thought of an example and asked him to translate it to finish his job. I don't think he can, and I think it's telling that all of you are jumping on the "muddy the waters, quick!" bandwagon.

Shayne

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Shayne,

For the sake of accuracy, there is a specific meaning for the term "pseudoscience" that the more science-oriented on OL use. Here is the Wikipedia article that explains it pretty well: Pseudoscience.

Notice that the standard for arriving at this meaning of "pseudoscience" is "scientific method," which is another term that has a specific meaning in common usage among these posters. This is a good time to define one's terms, although that is unnecessarily complicated (see below).

I sometimes get exasperated because science-oriented posters often presume that their meanings are the only meanings possible and do not even entertain the notion that another person could be using a different meaning for these terms. (I don't mean all science-oriented posters, just a few.) And if you really press hard, you see that Popper's falsifiability principle is smack in the middle of "scientific method."

In one of his less finer moments, Popper also declared that it is folly to define one's terms. (He used a stolen concept to blank out integration and categories and arrive at "infinite regress.") I have personally encountered this as an excuse for flip-flopping on meanings when the discussion turns "competitive" (for some damn reason that I have yet to discern). What I have been able to detect, though, is that when a person wants to become competitive and "win an argument" instead of discuss an idea, there is no stopping his rhetoric. Flip-flopping on meanings is merely one of the rhetorical tools used.

This makes discussion very tedious when you are trying to figure out an idea with precision, or what a person means. I have done a lot of outside reading because of this. Rather than argue about it, I started looking at the sources cited and doing Google searches. That makes it a little clearer to see where they are coming from. Also, I feel I have become enriched with this research, irrespective of the discussions. (Obviously this is an ongoing process.)

Now here is the weird part. For some other damn reason, snarkiness often reigns supreme (on all sides) in these discussions. From observing behavior alone, I have to conclude that there is some personal value gained by the participants for insisting on this. But there are two premises that need to be abandoned if these discussions are ever to attain some kind of intellectual value, one premise on each side:

Premise 1: Rand was a deluded fool and anyone who adheres to Objectivism is a superficial idiot who should not be allowed to pronounce the word "science."

Premise 2: Modern scientists, science professors and science philosophers are whim-infested, evasive, out-of-focus, death-worshiping maggots.

:)

Michael

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Daniel and you [ES] are merely objecting that I called it "pseudo-scientific" without saying why. Yes, it was a taunt, a dare for Dragonfly to show otherwise, because I really don't think that he can. You two are being like little children who don't understand what Daddy Dragonfly said but are supporting him anyway. I'd repeat to you what I did to Daniel that you're not qualified to be asking me questions or making corrections, you don't even comprehend what Daddy said.

The hell I don't. I'm rather surprised that you don't, however. I had thought that you're an engineer. Was I wrong about that? (I think I recall James H-N saying back when you started posting here that he was glad to have another engineer aboard. Haven't time to search right now.)

Ellen

___

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In one of his less finer moments, Popper also declared that it is folly to define one's terms. (He used a stolen concept to blank out integration and categories and arrive at "infinite regress.")

Michael, I'm going to let the rest of your comments go, but I must protest to that. Popper did not say that it's "folly to define one's terms," instead that it's folly to insist that there's some correct, dictated by Reality, as it were, meaning of a term.

I'm short on time, and I want to type in some stuff from Hospers on another thread if I get a chance later tonight. So it's likely to be awhile before I come back to this thread. Meanwhile -- I hope Daniel won't mind my saying this, but in case people wonder why he's disappeared...he's had a family emergency arise and is expecting to be away from listlife for awhile.

Ellen

___

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Daniel and you [ES] are merely objecting that I called it "pseudo-scientific" without saying why. Yes, it was a taunt, a dare for Dragonfly to show otherwise, because I really don't think that he can. You two are being like little children who don't understand what Daddy Dragonfly said but are supporting him anyway. I'd repeat to you what I did to Daniel that you're not qualified to be asking me questions or making corrections, you don't even comprehend what Daddy said.

The hell I don't.

The hell you do. That's why you're making a bunch of totally irrelevant noise rather than answering my *trivial* question.

Shayne

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Daniel and you [ES] are merely objecting that I called it "pseudo-scientific" without saying why. Yes, it was a taunt, a dare for Dragonfly to show otherwise, because I really don't think that he can. You two are being like little children who don't understand what Daddy Dragonfly said but are supporting him anyway. I'd repeat to you what I did to Daniel that you're not qualified to be asking me questions or making corrections, you don't even comprehend what Daddy said.

The hell I don't.

The hell you do. That's why you're making a bunch of totally irrelevant noise rather than answering my *trivial* question.

Shayne

Shayne, your question is far removed from being "trivial." And, again, I'm puzzled by your approach, since I was of the belief that you had some decent science background yourself, but on the other hand I think that if you did, you would be aware how far removed from trivial your example is.

Over and out on this thread for now.

Ellen

___

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Shayne, your question is far removed from being "trivial." And, again, I'm puzzled by your approach, since I was of the belief that you had some decent science background yourself, but on the other hand I think that if you did, you would be aware how far removed from trivial your example is.

Your definition of science is corrupted if you think that my example shouldn't be trivial. If a simple everyday statement can't be framed in the alleged language of science simply, then that language is bogus.

Over and out on this thread for now.

Thank you.

Shayne

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Michael, I'm going to let the rest of your comments go, but I must protest to that. Popper did not say that it's "folly to define one's terms," instead that it's folly to insist that there's some correct, dictated by Reality, as it were, meaning of a term.

Ellen,

Well, I admit he didn't use the word "folly." He used some other descriptive terms like

"prejudice(s),"

"a definition cannot establish the meaning of a term,"

"vague and confusing,"

"untenable,"

"I deny that the attempt to define them can improve matters,"

"it can only make matters worse,"

"increase the vagueness and confusion,"

"lead to an empty controversy about words,"

and claimed that defining terms leads to "infinite regression of definitions."

I retrieved these pearls of erudition from his essay Two Kinds of Definitions (1945) (of which I am obviously critical). I have quoted the passage below with the terms I cited in bold to show that they are Popper's words, not mine, and I am giving them in their context by providing the full quote.

Now you may think Popper could say all that and not consider it to be "folly" to engage in it, but I will just have to disagree with you. I don't see how he (or anyone else for that matter short of the mentally deficient) could considered doing something that is vague and confusing, untenable, results in empty controversies, etc., can be anything but folly. These descriptions certainly do not pertain to anything serious or productive. Thus, Popper not only implied that it was folly to define one's terms, he explicitly said that it made matters worse to do so!

As to your explanation about what Popper really meant, please forgive me, but I prefer to stay with Popper's own words for evaluating his ideas. The reader can judge as he sees fit. Here they are from the horse's mouth:

The second doctrine to be criticized has even more important connections with modern views; and it bears especially upon the problem of verbalism. Since Aristotle, it has become widely known that one cannot prove all statements, and that an attempt to do so would break down because it would lead only to an infinite regression of proofs. But neither he nor, apparently, a great many modern writers seems to realize that the analogous attempt to define the meaning of all our terms must, in the same way, lead to an infinite regression of definitions. The following passage from Crossman's Plato Today is characteristic of a view which by implication is held by many contemporary philosophers of repute, for example, by Wittgenstein: '. . . if we do not know precisely the meaning of the words we use, we cannot discuss anything profitably. Most of the futile arguments on which we all waste time are largely due to the fact that we each have our own vague meaning for the words we use and assume that our opponents are using them in the same sense. If we defined our terms to start with, we could have far more profitable discussions. Again, we have only to read the daily papers to observe that propaganda (the modern counterpart of rhetoric) depends largely for its success on confusing the meaning of the terms. If politicians were compelled by law to define any term they wished to use, they would lose most of their popular appeal, their speeches would be shorter, and many of their disagreements would be found to be purely verbal.' This passage is very characteristic of one of the prejudices which we owe to Aristotle, of the prejudice that language can be made more precise by the use of definitions. Let us consider whether this can really be done.

First, we can see clearly that if 'politicians' (or anybody else) 'were compelled by law to define any term they wished to use', their speeches would not be shorter, but infinitely long. For a definition cannot establish the meaning of a term any more than a logical derivation can establish the truth of a statement; both can only shift this problem back. The derivation shifts the problem of truth back to the premises, the definition shifts the problem of meaning back to the defining terms (i.e., the terms that make up the defining formula). But these, for many reasons, are likely to be just as vague and confusing as the terms we started with; and in any case, we should have to go on to define them in turn; which leads to new terms which too must be defined. And so on, to infinity. One sees that the demand that all our terms should be defined is just as untenable as the demand that all our statements should be proved.

At first sight this criticism may seem unfair. It may be said that what people have in mind, if they demand definitions, is the elimination of the ambiguities so often connected with words such as 'democracy', 'liberty', 'duty', 'religion', etc.; that it is clearly impossible to define all our terms, but possible to define some of these more dangerous terms and to leave it at that; and that the defining terms have just to be accepted, i.e., that we must stop after a step or two in order to avoid an infinite regression. This defence, however, is untenable. Admittedly, the terms mentioned are much misused. But I deny that the attempt to define them can improve matters. It can only make matters worse. That by 'defining their terms' even once, and leaving the defining terms undefined, the politicians would not be able to make their speeches shorter, is clear; for any essentialist definition, i.e. one that 'defines our terms' (as opposed to the nominalist one which introduces new technical terms), means the substitution of a long story for a short one, as we have seen. Besides, the attempt to define terms would only increase the vagueness and confusion. For since we cannot demand that all the defining terms should be defined in their turn, a clever politician or philosopher could easily satisfy the demand for definitions. If asked what he means by 'democracy', for example, he could say 'the rule of the general will' or 'the rule of the spirit of the people'; and since he has now given a definition, and so satisfied the highest standards of precision, nobody will dare to criticize him any longer. And, indeed, how could he be criticized, since the demand that 'rule' or 'people' or 'will' or 'spirit' should be defined in their turn, puts us well on the way to an infinite regression so that everybody would hesitate to raise it? But should it be raised in spite of all that, then it can be equally easily satisfied. On the other hand, a quarrel about the question whether the definition was correct, or true, can only lead to an empty controversy about words.

Thus the essentialist view of definition breaks down, even if it does not, with Aristotle, attempt to establish the 'principles' of our knowledge, but only makes the apparently more modest demand that we should 'define the meaning of our terms'.

If this is applied to anything but Aristotelian essentialism (and I have read Popper followers who do this), I find an enormous stolen concept in the middle of all that. (For the record, the stolen concept is equating the prioritization of observations dealing with causality with "intuitive knowledge," then dismissing causal agents altogether, but allowing words to remain as some kind of "tags" to label random observations and those loosely grouped together by, er... whatever pops up that one feels like grouping them with.) I know of very few people who adhere to Aristotelian essentialism and, to be precise, Popper was talking about modern usage of language. So I find the stolen concept applies to this extension.

But you think for some reason that Rand's concept of essential is the same as Aristotle's, so I do not want to rehash what has already been hashed. I mentioned the above more in the sense to be on record than to discuss the "beaten to death." I don't expect you to agree with me.

Michael

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...the definition shifts the problem of meaning back to the defining terms (i.e., the terms that make up the defining formula). But these, for many reasons, are likely to be just as vague and confusing as the terms we started with; and in any case, we should have to go on to define them in turn; which leads to new terms which too must be defined. And so on, to infinity.
My emphasis.

Here I would disagree slightly with Popper. This process may go on for an infinite length of time but not without repetition. In other words, we would actually define around in circles ie. define 'point' using the word 'space' and 'space' using the word 'point'. You can see this quite easily if you try yourself or look carefully at dictionaries.

that it is clearly impossible to define all our terms, but possible to define some of these more dangerous terms and to leave it at that; and that the defining terms have just to be accepted

This is in fact what we have to do in order to communicate.

Edited by general semanticist

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~ Well, getting away from the segued args about "Who's said/meant 'X' first?" and pseudo-science and causality and whatnot tangents, and getting back to Mike11's original question...

...Einstein, in making his math-'assumption' (ie: starting point) that light has a measurably constant vacuum-speed (measured [and, here's the prob] from whatever 'moving' framework), rather than the expectable (so-called 'intuitive', but really quantitively measured often 'till checks on photons) 'Galilean' A+B=A+B, I do believe empirically accepted this from the observations of the astronomer W. de Sitter (Ba'al can correct me on that.) De Sitter had compared/measured the approaching edge of a galaxy with its receding edge, and found light-speed measures in both were identical. Where Al generalized/(assumed?)/induced was that such implied that THIS was what Maxwell's equations empirically would refer to re 'c.' There, 'c'+B='c.'

LLAP

J:D

Edited by John Dailey

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ADDENDUM:

~ Needless to say, considering a 'speed' (er, properly 'velocity') of entity 'X' as staying unchanged regardless your own presumed speed relative to it, plays a bit of havoc with 'time' if Galilean A+B does not = A+B...when A=(or even approaches) 'c.'

LLAP

J:D

Edited by John Dailey

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ADDENDUM:

~ Needless to say, considering a 'speed' (er, properly 'velocity') of entity 'X' as staying unchanged regardless your own presumed speed relative to it, plays a bit of havoc with 'time' if Galilean A+B does not = A+B...when A=(or even approaches) 'c.'

LLAP

J:D

See http://en.wikipedia.org/wiki/Galilean_transformation

for the Galilean Transform. Under a Galilean Transform time is left invariant and simultaneity is absolute.

Newtonian Mechanics is Galilean Invariant. That is to say the coordinates of two inertial systems moving with a uniform velocity are related by a Galilean Transform

Contrast this with Einstein's formulation which requires the Lorentz Transform and invariance of the space-time interval. In this regime neither length nor time is preserved when one inertial system moves with uniform velocity with respect to another.

See http://en.wikipedia.org/wiki/Lorentz_transform

Ba'al Chatzaf

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Mike:

>But you think for some reason that Rand's concept of essential is the same as Aristotle's, so I do not want to rehash what has already been hashed.

For the nth time: no she doesn't. Nor do I. Nor does anyone else who understands the difference between the essentialist method and the essentialist goal.

But I agree: rather than rehash it, we'll just have to wait for that "technical" presentation you've been promising us on Rand and Popper then.

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Exerpt from the letters below:

A laser emits photons that all have the same mass, i.e., all have the same energy. You observe them while standing on the sidewalk, and measure their mass. Then you observe them again while moving toward the laser at 35 miles per hour, and measure their mass. Just as when you observed the car from two different viewpoints, you will find their mass to be greater! This is an instance of "violet shift".

End quote

If a spaceship is approaching the speed of light, its mass increases . . . but a photon’s mass is how much more at light speed plus 35MPH? Once again, I am beyond my depth. I thought nothing could go faster than the speed of light, so how can a photon be heavier, as if it were going faster than the speed of light?

Peter

Here is a thread called Speed.

From: Ram Tobolski <rtb_il@yahoo.com>

To: OWL <objectivism@wetheliving.com>

Subject: OWL: Re: Concepts of Science: Movement, and the Paradox of the Arrow

Date: Tue, 12 Mar 2002 00:06:06 +0200

Concerning my mentioning of the concept of momentary speed, and of its alleged importance during the birth of modern science, Dan Gibson wrote:

<< Next, there isn't any speed during a moment. Speed is a relationship, it needs two points to exists. In order to derive a "momentary speed", reference would need to be made to a previous moment. i.e. two snapshots, with location data and time data, then and only then can a speed be derived. >>

This is a welcome response. We can probably better understand the confusing concept Momentary Speed by examining what kind of concept Speed is.

Dan says that speed is a "relationship". It is not so clear to me what does he mean by "relationship". We have in philosophy that distinction between "property" and "relation". A Property belongs to one thing, or to a part of it, for example "x is red". A relation connects two or more things, for example "x is taller than y".

Initially, at least, Speed seems to be a property, not a relation. It is a property of a body, one body.

But, next, speed (like most properties) is relative to time. A body may have speed s1 at time t1 and speed t2 at time t2.

What Dan says, apparently, is that Speed is not intelligible at a moment, but only between two moments. Not "x has speed s1 at the moment t1" but "x has speed s1 between the moments t1 and t2". What would the speed, numerically? I guess d/(t2-t1), where d is the distance that x traversed between the times t1 and t2. Speed is distance divided by time.

I disagree. The speed that Dan seems to be referring to is the _average_ speed in the interval between t1 and t2. But like the average person, which is no person in particular, the average speed is no speed in particular.

Speed, I say, is a property of a body in a _single_ moment. To prove this, I invite you to think about the _impact_ of a falling body, e.g. a stone. Let's say I drop a stone from the roof of my house. Imagine the impact of the stone if it hits something after it falls one meter. Now imagine the impact of the stone if it hits something after it falls ten meters.

The impact of the stone, we know from Newton, is m*v, where m is the mass of the stone, and v is the velocity (speed) of the stone _at_the_moment_of_impact_ (I ignore the effects of the shape of the stone).And since the mass of the stone is constant during the fall, the impact is proportional to the speed at_the_moment of impact. It is not dependent on any other moment.

So, speed is a momentary property. It is not that the moment exists "in isolation". The speed of a body at a moment says something about the movement of the body "in the environment" of that moment. Not in any set environment, in any environment, as small as we please. The speed at a moment thus depends somehow on the neighboring moments, but is does not depend on any one moment in particular.

About Dan's distinction between "existence" and "occurrence": I'll welcome further thoughts on this subject.

Ram

From: Ram Tobolski <rtb_il@yahoo.com>

To: objectivism@wetheliving.com

Subject: OWL: Re: Concepts of Science: Movement, and the Paradox of the Arrow

Date: Tue, 12 Mar 2002 01:54:51 -0800 (PST)

David Potts keeps saying that he has nothing new to say about the subject, and then surprisingly he says something new and important. Keep it up...

David quoted my quotation of Aristotle's response to Zeno's paradox of the arrow:

>Here is what he [sc. Aristotle] wrote (Physics book VI >section 9, pages 239b5-239b8):

>

>"Zeno's reasoning is invalid. He claims that if it is always true that a thing is at rest when it is opposite to something equal to itself, and if a moving object is always in the now, then a moving arrow is motionless. But this is false, because time is not composed of indivisible nows, and neither is any other magnitude."

>

>In other words, moments ("nows") do not exist. And furthermore, extensionless points do not exist, in any context!

And then he replies:

<< I do not think that the correct way to interpret Aristotle's often repeated claims that "time is not composed of individual nows" and a magnitude is not composed of points is to say that moments and points do not exist. Aristotle certainly believed that moments and points do exist. His point was rather that spans of time and magnitudes of space are not _composed_ of indivisible nows or extensionless points. >>

David says, then, that Aristotle did not intend that "nows" or moments (durationless, indivisible points of time) did not exist, but merely that time is not "composed" of them. Similarly, in geometry, that points do exist, but that lines are not "composed" of points.

What is this "composition" about? David writes:

<< If you tried to build a line by placing points next to one another, how long would it take? The answer is, _forever_! In fact, you could never even get started. For points don't take up any space (even in only one dimension). That is what it is to say that points are extensionless. Again, suppose you began dividing a line repeatedly into smaller and smaller segments. How long before you reach points? Obviously, as before, you

_never_ do. >>

So, by "composition" David seems to mean something like: Lines cannot be _constructed_ from points in a finite process, in a process that would take a finite amount of time.

This is of course true, because the number of points in a line (if we agree that there are points in a line) is infinite.

However, I cannot agree that this was Aristotle's position, i.e. that indivisible moments did exist, but that intervals of time could not be constructed out of moments. And I can presents two reasons for my disagreement, one more specific and immediate and one more general and remote:

1. If this were Aristotle's position, it would be no answer to the paradox of the arrow! The paradox of the arrow concerns a _single_ moment, a single point. So to the paradox of the arrow it is immaterial whether lines can be constructed of points or not. It is merely about a single point!

David had in mind, perhaps, another one of Zeno's paradoxes, which is known (if I recall) as the Dichotomy. It says, briefly, that if you intend to cover a distance of one mile, you have to cover a distance of half a mile first. Again, you have to cover a distance of quarter of a mile first. And so on, ad infinitum. Therefore it seems that you can never get started...

2. The idea of construction, which David relates to Aristotle, was actually alien to Aristotle's thought, as far as I'm presently acquainted with it, even outside the context of infinity. In general, in Aristotle's thought wholes were never constructed out of their parts. A human body, for example, is not constructed out of its organs. An arm gets to be a living organ because it is part of a living body, and not the other way around! Even a house is not constructed out of bricks, cement etc. All these are necessary, but not sufficient. As Aristotle would put it, the essence of the house is its form; and the cause of a house's form is not the forms of its parts, but the idea of the house's form in the architect's mind.

Aristotle was a holist, in this sense. For him, wholes were prior to their parts.

Ram

From: Michael Hardy <hardy@math.mit.edu>

To: atlantis@wetheliving.com

Subject: ATL: Massless stuff

Date: Tue, 17 Sep 2002 17:20:39 -0400 (EDT)

(Andy Dufresne's and Ellen Stuttle's comments are quoted below my .sig .)

The idea is that photons have no _rest_ mass, but they have mass while in motion at the speed of light. The finite mass they have while moving could be said to be infinite by comparison to the zero mass they would have at rest, if they could be at rest.

As for mass dilation: You observe a car to have a certain mass as it passes you at 35 miles per hour while you stand on the sidewalk. Then you observe the same car as it moves at 35 miles per hour and you are in another car moving in the _opposite direction_ at 35 miles per hour. Now it is moving at 70 miles per hour relative to you. That is a higher speed than 35 miles per hour, so you observe its mass to be greater. THE SAME THING HAPPENS WITH PHOTONS! A laser emits photons that all have the same mass, i.e., all have the same energy. You observe them while standing on the sidewalk, and measure their mass. Then you observe them again while moving toward the laser at 35 miles per hour, and measure their mass. Just as when you observed the car from two different viewpoints, you will find their mass to be greater! This is an instance of "violet shift".

Q: What is the Doppler effeect?

A: The Doppler effect is the annoying noise made by the whistle on a passing train.

Mike Hardy

> >Hi,

> >

> >I've read some of this talk about whether there exist massless moving things and I'm terribly confused about something. I don't understand how photons could have mass. Doesn't mass increase towards infinity as speed increases towards the speed of light? If photons had mass, wouldn't their mass be infinite due to the fact that they're moving at the speed of light?

Andy Dufresne

I think the answer to your question is that photons aren't accelerating -- they're moving at constant speed -- and the mass increase you're talking about pertains to something which is accelerating. I'll ask my husband when he gets home tonight (he teaches late on Tuesdays) if that's the correct answer. Or meanwhile, if Dennis is reading, he might want to answer.

Ellen S.

From: "Gayle Dean" <gwwdean@bellsouth.net>

To: "Atlantis" <Atlantis@wetheliving.com>

Subject: ATL: Re: Doppler Effect

Date: Tue, 17 Sep 2002 17:37:35 -0400

Mike Hardy said:

>A: The Doppler effect is the annoying noise made by the whistle on a passing train.

Dopeler Effect: the tendency of stupid ideas to seem smarter when they come at you rapidly.

Gayle

From: Andrew Taranto <ataranto@verizon.net>

To: <atlantis@wetheliving.com>

Subject: ATL: Massless stuff

Date: Tue, 17 Sep 2002 16:49:47 -0500

Mike Hardy wrote:

'As for mass dilation: You observe a car to have a certain mass as it passes you at 35 miles per hour while you stand on the sidewalk. Then you observe the same car as it moves at 35 miles per hour and you are in another car moving in the _opposite direction_ at 35 miles per hour. Now it is moving at 70 miles per hour relative to you. That is a higher speed than 35 miles per hour, so you observe its mass to be greater. THE SAME THING HAPPENS WITH PHOTONS! A laser emits photons that all have the same mass, i.e., all have the same energy. You observe them while standing on the sidewalk, and measure their mass. Then you observe them again while moving toward the laser at 35 miles per hour, and measure their mass. Just as when you observed the car from two different viewpoints, you will find their mass to be greater! This is an instance of "violet shift".'

So wouldn't it be better to say, rather then "mass is a property of entities," that "mass is a property of the ~relation between~ two entities (i.e., the spatio-temporal relation)?" In other words: wouldn't mass of A vary from observer to observer, according to each observer's respective motion considered relatively to A?

If mass is a property of the relation between entities, is there a concept that applies more to conventional notions of mass (e.g., "a clump-mass"), a measure that doesn't vary with velocity or observers' velocity?

Here's a conundrum: suppose two spaceships x and y flying towards each other, but not directly (i.e., so they will pass by each other, just out of side swiping range). Both have a velocity of over 1/2 c, but less than c: to observers on x, y "appears" to move at some multiple of c (greater than 1, but less than 2), and vice versa.

- At what point would observers on x be able to see y? Only at some point after y actually passes x, since the relative velocity is >c? - What mass would observers on x measure y as having? I.e., if an entity’s mass approaches infinity as it's velocity approaches c, what happens when a relative velocity is >c? Or could you deduce from this that the practical ceiling on velocity is 0.5c, rather than c?

Andrew Taranto

From: Ellen Stuttle <egould@mail.hartford.edu>

To: atlantis@wetheliving.com

Subject: Re: ATL: ALT: Massless Motion?

Date: Tue, 17 Sep 2002 17:16:24 -0400

Michael Carrigher writes:

>Is massless motion the same thing as "entityless" action? If not, how do the two differ? If so, isn't the whole concept a contradiction due to the conflation of epistemology (knowledge of the measurement of subatomic particles) and metaphysics (the reality of the existence of subatomic particles)?

>

>If I have this right, massless motion is hypothesized due to the inability to measure precisely the mass of various subatomic particles that nonetheless appear to have motion. But the inability to precisely measure the mass of some subatomic particle does not mean that it does not exist as an entity with some mass. It just means that we cannot measure that mass with current technology.

>

>Just as an action must have an entity that caused that action based on or derived from the entity's identity (law of causality), wouldn't a motion require a mass that caused that motion based on or derived from the mass's identity (law of causality, again)? Or am I missing something?

>

>Michael

>I am a psychologist and not a physicist, so it is at least conceivable that I might have missed something.

Michael,

Please see my post from yesterday titled "Mass/Matter...." It seems, from your speaking of "a mass," that you're thinking of "mass" as if it's an entity instead of a property of an entity. Why I find the term "massless motion" odd, as I indicated in a post today to Jason, is because it combines two aspects in a peculiar blend. I'm waiting to learn if Hall really does use the term "massless motion" – and if he does, what he means by it. Since "mass" is the property that results in *resistance* to change of motion ("an entity at rest remains at rest and an entity in motion remains in uniform motion, unless acted on by an external force"), I don't know what "massless motion" *could* mean.

Ellen S.

From: Ellen Stuttle <egould@mail.hartford.edu>

To: atlantis@wetheliving.com

Subject: Re: ATL: ALT: Massless Motion?

Date: Tue, 17 Sep 2002 17:16:24 -0400

Michael Carrigher writes:

>Is massless motion the same thing as "entityless" action? If not, how do the two differ? If so, isn't the whole concept a contradiction due to the conflation of epistemology (knowledge of the measurement of subatomic particles) and metaphysics (the reality of the existence of subatomic particles)?

>

>If I have this right, massless motion is hypothesized due to the inability to measure precisely the mass of various subatomic particles that nonetheless appear to have motion. But the inability to precisely measure the mass of some subatomic particle does not mean that it does not exist as an entity with some mass. It just means that we cannot measure that mass with current technology.

>

>Just as an action must have an entity that caused that action based on or derived from the entity's identity (law of causality), wouldn't a motion require a mass that caused that motion based on or derived from the mass's identity (law of causality, again)? Or am I missing something? >

>Michael

>

>I am a psychologist and not a physicist, so it is at least conceivable that I might have missed something.

Michael,

Please see my post from yesterday titled "Mass/Matter...." It seems, from your speaking of "a mass," that you're thinking of "mass" as if it's an entity instead of a property of an entity. Why I find the term "massless motion" odd, as I indicated in a post today to Jason, is because it combines two aspects in a peculiar blend. I'm waiting to learn if Hall really does use the term "massless motion" – and if he does, what he means by it. Since "mass" is the property that results in *resistance* to change of motion ("an entity at rest remains at rest and an entity in motion remains in uniform motion, unless acted on by an external force"), I don't know what "massless motion" *could* mean.

Ellen S.

From: "Michael Carriger" <michaelcarriger@hotmail.com>

To: atlantis@wetheliving.com

Subject: ATL: ALT: Massless Motion?

Date: Tue, 17 Sep 2002 19:57:54 +0000

Is massless motion the same thing as "entityless" action? If not, how do the two differ? If so, isn't the whole concept a contradiction due to the conflation of epistemology (knowledge of the measurement of subatomic particles) and metaphysics (the reality of the existence of subatomic particles)?

If I have this right, massless motion is hypothesized due to the inability to measure precisely the mass of various subatomic particles that nonetheless appear to have motion. But the inability to precisely measure the mass of some subatomic particle does not mean that it does not exist as an entity with some mass. It just means that we cannot measure that mass with current technology.

Just as an action must have an entity that caused that action based on or derived from the entity's identity (law of causality), wouldn't a motion require a mass that caused that motion based on or derived from the mass's identity (law of causality, again)? Or am I missing something?

Michael

I am a psychologist and not a physicist, so it is at least conceivable that I might have missed something.

From: Ellen Stuttle <egould@mail.hartford.edu>

To: atlantis@wetheliving.com

Subject: ATL: Source Book (was RE: Massless stuff)

Date: Wed, 18 Sep 2002 00:15:01 -0400

Bill Dwyer asked:

>Would someone please define "mass," as it is used here?

The definition I'm using is one commonly used in modern physics: that property of an object which results in its inertia.

The relationship to inertia has been key since Newton's time, but there's a complex history of changing notions of the exact meaning of "mass."

>And, if possible, would he or she be so kind as to relate this definition to the commonly understood meaning of "mass" as "a unified body of matter"?

Mass as defined by Newton (this is paraphrasing, not exact quoting) was a quantity measured by the joint product of an object's bulk and density. The feature which links the meaning of "mass" as "a unified body of matter" and physics definitions is, I suppose, that of density.

A book Larry recommends for those interested in the subject is *Concepts of Mass in Classical and Modern Physics*, by Max Jammer, Copyright 1961 by the President and Fellows of Harvard College, Harper Torchbook edition, 1964. That book of course doesn't include the last 40 years' debate on the definition and nature of mass, but it gives a good historic background for the prelude to current debates.

Ellen S.

From: Ellen Stuttle <egould@mail.hartford.edu>

To: atlantis@wetheliving.com

Subject: Re: ATL: Massless stuff

Date: Tue, 17 Sep 2002 23:49:05 -0400

Dennis wrote:

>Per Penrose's work in the late 80's or early 90's [discussed at length in Physics Today] momentum rather than mass should be used when discussing relativistic energy changes. The use of mass leads to contradictions between reference frames when general relativity is brought into the picture [an observation known before Penrose spelled out some of the theoretical reasons to use P (momentum instead of mass)]. I do not know if current relativity classes/texts are teaching about this correct usage or not....

Larry remembers the Physics Today issue Dennis is talking about, and says he's been meaning to restudy that debate if he gets a chance one of these days (he's been teaching other subjects besides relativity in recent years).

In brief, for entities with positive rest mass:

momentum = relativistic mass x velocity

where:

relativistic mass = rest mass x a speed-dependent function

The general idea proposed, as I understand it (any errors are mine), was to use the term "mass" ONLY for rest mass, which would then be either zero (photons and gravitons, if the latter exist) or a positive value. The relativistic energy changes would then be accounted for by the speed-dependent function, instead of being called "relativistic mass."

Larry says he thinks that how the concept of mass is currently taught varies, though teaching it in the way Dennis considers incorrect is the usual way. (Dennis of course *presumes* that his preferred solution is "correct," as if there's no possible intelligent reason for the other solution. It's a little hard, though, to believe that a solution favored by Penrose would be ignored due to resistance from "the establishment," since you'd have to look a long way to find anyone more "establishment" than Penrose. ;-))

Ellen S.

From: Michael Hardy <hardy@math.mit.edu>

To: atlantis@wetheliving.com

Subject: ATL: Re: Massless stuff

Date: Wed, 18 Sep 2002 18:50:36 -0400 (EDT)

> Mike Hardy on photons:

>

>"THE SAME THING HAPPENS WITH PHOTONS! A laser emits photons that all have the same mass, i.e., all have the same energy. You observe them while standing on the sidewalk, and measure their mass. Then you observe them again while moving toward the laser at 35 miles per hour, and measure their mass. Just s when you observed the car from two different viewpoints, you will find their mass to be greater! This is an instance of "violet shift"."

>

> Are you sure about that?

As a non-physicist I'll be cautious and say I'm sure that's what's conventionally taught.

> Wouldn't the relative speed of a photon measured by an observer always be the same?

Yes.

>I thought that the speed of light was constant, irrespective of reference frame. So if you're moving at 35 or 6.7*10^8 mph relative to the photon, you'd observe it to be moving at c...

Right.

>and so its mass wouldn't vary with the relative speed of the observer because the relative speed of the observer could only be c. Right?

Wrong. The faster you move toward it the more massive, and concommitantly, the more energetic, you will find it to be. That's violet shift.

> The "violet shift" (I thought it was "blue shift") occurs

(I've heard "violet shift", but I'm not going to be fussy about the name. Either way, it's the opposite of "red shift", except that if I had written about red shift, I'd still have been writing about the same phenomenon.)

>because the photons hit the observer at a higher frequency; but they always come at the same speed, mass, and momentum... right?

Same speed, yes. But remember something from high-school physics: E = h nu, i.e., energy of a photon is proportional to frequency. So if it shifts in the "violet" direction, so that you have a higher frequency, then each photon has a higher energy.

Mike Hardy

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MSK: Spammer.

Classical physics is wrong.

Next question?

Ba'al Chatzaf

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