Zeno Paradox

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  • #26
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I think even Zenoman must agree with you there Dave.
 
  • #27
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The point of Zeno’s arguments is he was used the logic of those that believe things do move “pluralists” to construct a paradox based on their own pluralist rules of movement that reduces to an absurd result; therefore refuting as absurd the idea that anything moves at all;
Thus supporting Zeno’s monism (what today we would call “Absolute Monism”) which believe that all is just one thing within which we and everything only exist as essentially an idea with nothing real actually moving.
While I don't doubt that you're making a valid point, I cannot understand what you are saying, especially in the above. It is grammatically so poorly-formed as to be unintelligible.
Sorry the word “was” should have been edited out –
however I suspect your trouble is not with the language so much as following the thought processes involved in formal logic.
I’ll attempt to translate phrase by phrase:

[The point of Zeno’s arguments is he used the logic of those that believe things do move “pluralists”]
pluralists Zeno's opponents “believe things do move” - most of use do too.
Zeno did not believe ANYTHING “moved”.
Zeno’s favored methods - reducing a argument to the absurd - requires taking your opponents position to explain some problem with the ultimate objective to assert something so ridiculous as to make you opponents look foolish. (I suspect he was rather “rude” about it)

[ to construct a paradox based on their own pluralist rules]
The problem of course must be stated and rigorously worked out in the rules of his opponent.
In this case it is clear rules of movement require any thing must first cross half the distance to a line before it can EVER cross the line.

[that reduces to an absurd result]
One of the rules of “pluralists” is that space or distance can always be further divided. (kind of gets into can space be quantized or not).
With that for Zeno it was clear that there would always be a halfway point the must first be traveled before the Line could EVER be reached – and logically EVER becomes NEVER.
AS the line can NEVER be reached since there will always be a halfway point that must be reached first!

[therefore refuting as absurd the idea that anything moves at all]
Zeno was not saying an object could move but not reach the goal, He was saying that since the very rules of movement could not justify the goal being reached was an absurd result based on the idea of motion - Therefore the rules and very idea of movement at all was absurd.

[Thus supporting Zeno’s monism (what today we would call “Absolute Monism”)]
He was supporting his own “religious science” of monism.

[believe that all is just one thing]
His version was not that elements divided down to smaller things eventually reaching just one element single identical form that made up earth wind and fire (or quarks electrons etc.) from which all other things are made. When he said "one thing" he meant just one single non-moving thing.

[within which we and everything only exist as essentially an idea]
Meaning that everything we see and even ourselves do not exist, Reality is within that one thing where we are just thoughts or ideas with thoughts and ideas of our own.

[ with nothing real actually moving. ]
Not even within that one thing is any movement needed; only ideas with ideas unknown to other ideas with its own ideas; all existing without need of any physical movement; certainly not the kind of motion we think we are seeing in our misguided view of reality.

The problem is most do not approach Zeno on the terms he established for the paradox. Which makes the debate pointless. And under Zeno's terms most true philosophers recognize that these paradoxes have not been resolved at least not in favor of rational science.


It is absurd to debate Zeno or attack his logic if you don’t understand or know what he was arguing or under what terms he made his points. Maybe it can be translated into scientific terms but it has not been here.
I have my own way of kicking Zeno’s arguments to the curb (which is where I and most think they belong) but it is too long for here and IMO it is a logic debate not a science forum issue.
And the closest we have to a logic forum is the Philosophy Forum.
 
  • #28
Hurkyl
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The problem is most do not approach Zeno on the terms he established for the paradox.
On the contrary; most peoples' approach to this paradox is to demonstrate that the step
With that for Zeno it was clear that there would always be a halfway point the must first be traveled before the Line could EVER be reached – and logically EVER becomes NEVER.
AS the line can NEVER be reached since there will always be a halfway point that must be reached first!​
is not justified. In particular, they take their best guess as to what Zeno might have been thinking -- usually something like "each individual subgoal takes time, and so infinitely many subgoals must take infinitely much time" -- and actively demonstrate that the reasoning is invalid.

(To reject Zeno's argument, it is of course sufficient to simply point out the lack of justification for this step. But it seems to be the popular practice to go beyond simply pointing out the omission and attempt to actually demonstrate the flaw)


Since (to the best of my knowledge) Zeno does not actually state his rationale for this step, we cannot be sure what he really thinking here. However, what Zeno really meant is a mostly irrelevant question, since we have the more practical matter of considering what people today are thinking when they consider this argument.
 
  • #29
rcgldr
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Going back to the bouncing ball with a fixed loss on each bounce. The ball bounces an infinite number of times in a finite amount of time. This is close to a real world example, except it there's a point when the bounce height is less than the deformation, but if the center of mass movement is used, then it's a close approximation to the idealized case where the number of bounces or vertical movements is infinite in a finite period of time.
 
  • #30
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Facing Zeno

On the contrary; most peoples' approach to this paradox is to demonstrate that the step
With that for Zeno it was clear that there would always be a halfway point the must first be traveled before the Line could EVER be reached – and logically EVER becomes NEVER.
AS the line can NEVER be reached since there will always be a halfway point that must be reached first!​
is not justified. In particular, they take their best guess as to what Zeno might have been thinking -- usually something like "each individual subgoal takes time, and so infinitely many subgoals must take infinitely much time" -- and actively demonstrate that the reasoning is invalid.
Nothing contrary in that demonstration at all, Zeno’s point was that using the reasoning based on motion is invalid – your agreeing with Zeno here.
(To reject Zeno's argument, it is of course sufficient to simply point out the lack of justification for this step. But it seems to be the popular practice to go beyond simply pointing out the omission and attempt to actually demonstrate the flaw)
But that is exactly what Zeno was hoping for – to show that when he uses the logic and rules of motion to build and argument, only a flawed absurd result is obtained – additional points about that flaw are points in Zeno’s favor – he appreciates the help. [/QUOTE] Since (to the best of my knowledge) Zeno does not actually state his rationale for this step, we cannot be sure what he really thinking here. [/QUOTE] Again, it is not his rational – it is our rational in believing in the rules for motion that he is applying against us! The modern knowledge of Zeno’s thinking is known - how he logically argues this point is included in advance modern philosophical logic, but is still based on the basic principles of logic (reducing to the absurd & begging the question) taught in Logic 101. Often scientist don’t included the more advanced training of Formal Logic in their training and knowledge. That is why many miss the point that Zeno wants his argument to be shown as absurd, because it is a argument based on motion – and that in the end was his objective – a logical debate demonstrate our ideas of motion were simply absurd.
Yes we are sure what he was thinking – that is want the Wiki information & links Jeff provided pointed out – Modern Experts in Formal Logic and Philosophical Debate know and understand very well what Zeno did and they tell use that a rebuttal to the Zeno proof against our believe in motion has never been made using sound formal logic. At a minimum those modern experts should be considered if you want to argue this issue.
However, what Zeno really meant is a mostly irrelevant question, since we have the more practical matter of considering what people today are thinking when they consider this argument.
And there it it is - the statement Zeno was waiting for as you debate him on the marble steps in Athens.
Zeno will say: Of course Hurkyl you are absolutely correct all that matters is “what people are thinking” just has I have defined Absolute Monism, not that when the imagine things like a bouncing ball that anything actually in fact moves – I glad to see you finally agree with my position.​
As he walks of laughing at both of us for believing things are real and really move; He has yet another debate victory. You are not the first his logic has defeated – you will not be the last.

Zeno is not an easy debate to face. Unless you only put up a strawman version of him.
 
  • #31
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Zeno appears to have been resurrected more times than Lazarus.
 
  • #32
Hurkyl
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Zeno’s point was that using the reasoning based on motion is invalid – your agreeing with Zeno here.
:confused: You seem to have completely misinterpreted me. Hopefully, the following is clear:
Zeno's argument is invalid.​
And just to make sure, I will point out that that is not the same thing as
Zeno presented a valid reductio ad absurdum.​

In fact, assuming the consistency of Peano arithmetic, Zeno's argument doesn't merely contain a gap: it is provably a non sequitur.


(In the above, by "Zeno's argument" I refer to what you have presented as his argument)
 
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  • #33
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pallidin said:
Zeno appears to have been resurrected more times than Lazarus.
I’m not aware of the sophism of Zeno have every haven been seriously “resurrected” - I’d need to see some credible reference for that. AFAIK that has been dead for centuries displaced by the accepted assumption that things do move.
Is that assumption supported by a legitimate refutation of Zeno’s Paradoxes? NO!
It should be clear that no such formal falsification has ever been provided, but reminding folks of that does not resurrect his science.

And when I say no formal falsification of the Zeno paradoxes has ever been provided that includes incomplete declarations and assumptions such as:
…. the following is clear:
Zeno's argument is invalid.​
In fact, assuming the consistency of Peano arithmetic, Zeno's argument doesn't merely contain a gap: it is provably a non sequitur. …
These assumptions here stated as facts directly contradict the claims made in the Wiki links about what real experts in formal logic say about them. If there is evidence for these claims then the Wiki information should be corrected.
I’m no expert but if they are “provably a non sequitur” or have been legitimately falsified that should be a big deal in the world of formal logic & reasoning.
Just show us the proof, peer reviewed not in a physics journal willing to accept assumptions, but a mathematics journal reviewed by real experts in formal logic.
To the best of my knowledge no such paper or proof has been accepted as complete – and the Wiki information is not a misrepresentation in need of correction.
 
  • #34
DaveC426913
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I thought that Zeno's paradox was resolved with the intro of the concept of "instantaneous velocity"? i.e how one can calculate a velocity as the duration approaches zero. That's the resolution is it not?
 
  • #35
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Just show us the proof,
I interpret "space" to mean Q³.
I interpret "time" to mean Q.
Let f be the function f(t) = (t, 0, 0).
I interpret "the line" to mean the line given by the equations x = 1, z = 0.
I interpret "Achilles reaches a point P" to mean that there exists a time t satisfying f(t) = P.
I interpret "Achilles reaches the line" to mean reaching any point satisfying the equations of the line.

Then, we observe that, in this model Achilles reaches each of the half-way points as well as the line. The existence of this model presupposes only Peano arithmetic, and thus proves the theorem
Peano arithmetic is consistent ==> Your presentation of Zeno's argument is an invalid argument.​

Did I not formalize it how you intended? Too bad, your fault for being imprecise. Does this not resemble the semantics you intended? Doesn't matter, I'm asserting you've made a formal fallacy. However, I don't believe I've made use of either of these freedoms in the above argument.


Just for fun...
ithat there would always be a halfway point the must first be traveled before the Line could EVER be reached – and logically EVER becomes NEVER.​
would you care to take a stab at justifying this passage?
 
  • #36
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Just for fun...
ithat there would always be a halfway point the must first be traveled before the Line could EVER be reached – and logically EVER becomes NEVER.​
would you care to take a stab at justifying this passage?
what is so hard about that?
Zeno uses our logic of motion and space to define a halfway point that will always be between our object and the finish line – if there is always something between it and the finish how can the finish ever be reached. As Zeno says this shows it cannot and will never be reached – he uses our rules of space and motion to produces absurd results, his paradox still stands.

These forums expect a statement like “Zeno's argument is an invalid argument” to be supported by more than a “Straw man” debate - you have an obligation to present obvious points Zeno would raise not just pretend he would stand mute.

Peano arithmetic is 19th century math on number theory – where is your justification to extending that to real distances that you assume can be traversed by things in motion. If you have only assumed that to be true then your just begging the question.
Do you really think Zeno would stand mute as if made of straw if we use such flawed logic?

If you don’t know what "begging the question" is, Too Bad open a book on logic. If you want to claim Zeno’s paradox’s as false arguments you need to use formal logic to do so.
If you really think the experts already motioned are wrong, name the peer reviewed papers that show that and use them to correct the Wiki Information to agree with your opinions. Keep us updated on your progress in that effort.

Otherwise just because I agree with the science of motion is no reason to accept your logic or assumptions like "instantaneous velocity" over Wikipedia information that real experts say these paradoxes have not been formally rejected.
 
  • #37
CRGreathouse
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Otherwise just because I agree with the science of motion is no reason to accept your logic or assumptions like "instantaneous velocity" over Wikipedia information that real experts say these paradoxes have not been formally rejected.
I'm surprised you put such faith in Wikipedia.
 
  • #38
Hurkyl
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what is so hard about that?
Zeno uses our logic of motion and space to define a halfway point that will always be between our object and the finish line – if there is always something between it and the finish how can the finish ever be reached. As Zeno says this shows it cannot and will never be reached – he uses our rules of space and motion to produces absurd results, his paradox still stands.
That is not a valid argument. Instead of using a chain of deductive reasoning to justify your conclusion, you are appealing to your ignorance about how the conclusion could fail.

This error is particularly egregious because you are not ignorant about how the conclusion could fail -- you are perfectly aware of the traditional calculus-based "sum of series" argument. (Which, according to Wikipedia, was already known as far back as Aristotle).



These forums expect a statement like “Zeno's argument is an invalid argument” to be supported by more than a “Straw man” debate - you have an obligation to present obvious points Zeno would raise not just pretend he would stand mute.
An "obvious" point Zeno would raise is
each individual subgoal takes time, and so infinitely many subgoals must take infinitely much time​
which I've already presented and invalidated in this thread. The only other "obvious" point I can imagine Zeno bringing up is
Each event in a ordered chain of events must either be the first event, or have an event immediately preceding it. Similarly for last and succeeding.​
which, incidentally, is tantamount to assuming a priori that infinite divisibility is impossible. But that's easily invalidated by pointing out there's no justification given for such an assumption. In fact, physics allows the order type chain of events can be any suborder of R.


But -- you've already rejected this method to refuting Zeno through a bit of sophistry1: you've pretended that such an argument is merely providing the other half of Zeno's contradiction rather than demonstrating an error in his reasoning. I pointed this out earlier, but you didn't bother to defend or retract your assertion. I didn't press the issue because I thought it interesting to take up another line of attack. But since you are pressing the issue, discussion cannot proceed until you address my objection.

1: Pun intended: I mean this in the pejorative sense.




As for the other line of attack -- I had assumed you were aware of some of the basic relationships between syntax and semantics: suppose we are considering whether or not a proposition P can be proven by deductive logic. One necessary condition is that P must be true in every semantic interpretation of our language -- no matter how strange or convoluted it might be. Contrapositively, if any interpretation can be constructed where P is false, then P cannot be proven deductively.

On the assumption that Peano arithmetic is consistent, I have provided an interpretation that serves as a counterexample. Furthermore, I assert that it's a 'reasonable' counterexample, on the grounds it's essentially the same as (a particular example of) the way we normally interpret the notions of 'space', 'time', and 'motion', except I have replaced the continuum R with the rational numbers.

Since your argument is informal, it can never be truly refuted, because you can always surprise us at the last minute and say "Haha, this whole time I was really making the a priori assumption that motion is impossible, I just never bothered to explicitly state it!" (of course, at this point we'd all dismiss your argument as vacuous) But I can (and have) refuted the particular argument you have put forth.
 
  • #39
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Since your argument is informal, it can never be truly refuted, because you can always surprise us at the last minute and say "Haha, this whole time I was really making the a priori assumption that motion is impossible, I just never bothered to explicitly state it!" (of course, at this point we'd all dismiss your argument as vacuous) But I can (and have) refuted the particular argument you have put forth.
That is impossible – I was clear that Zeno was presenting a argument based on the a priori assumption of motion to build an absurd result. You cannot possible be so dense as to miss that point.

If you seriously think that all philosophers agree with you, then site an authority in the field and have them see to that that Wikipedia is revised based on that authority to remove the statement:

However, some philosophers insist that the deeper metaphysical questions, as raised by Zeno's paradoxes, are not addressed by the calculus. That is, while calculus tells us where and when Achilles will overtake the Tortoise, philosophers do not see how calculus takes anything away from Zeno's reasoning that concludes that this event cannot take place in the first place. Most importantly, many philosophers do not see where, according to the calculus, Zeno's reasoning goes wrong …​

Absent that I’ll only be able to logically assume you are not really serious.
Your illogical logic resorting to insults disqualify you as useful as a mentor on this topic – so see you in another thread on another subject someday, but you and I are done in this one.
 
  • #40
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That is impossible – I was clear that Zeno was presenting a argument based on the a priori assumption of motion to build an absurd result. You cannot possible be so dense as to miss that point.

If you seriously think that all philosophers agree with you, then site an authority in the field and have them see to that that Wikipedia is revised based on that authority to remove the statement:

However, some philosophers insist that the deeper metaphysical questions, as raised by Zeno's paradoxes, are not addressed by the calculus. That is, while calculus tells us where and when Achilles will overtake the Tortoise, philosophers do not see how calculus takes anything away from Zeno's reasoning that concludes that this event cannot take place in the first place. Most importantly, many philosophers do not see where, according to the calculus, Zeno's reasoning goes wrong …​

Absent that I’ll only be able to logically assume you are not really serious.
Your illogical logic resorting to insults disqualify you as useful as a mentor on this topic – so see you in another thread on another subject someday, but you and I are done in this one.
Randall, you place relatively too much confidence in your authorities, and relatively too little confidence in your own ability to reason.

As someone who holds degrees in mathematics, physics, and philosophy, I hope you would consider that I agree with Hurkyl, for what it's worth. I believe that, for example, the rebuttal in post #35 is definitive.

If you truly wish to argue that Zeno's paradox is not resolved, then let us examine the article that is linked in the wikipedia web page:

http://philsci-archive.pitt.edu/archive/00002304/

I hope that anyone who has a moderate training in mathematics, logic, and philosophy will see that this paper only succeeds in supporting its premise in as much as it also trivializes Zeno's arguments. The author has a pompous attitude, and he callously makes claims of impossibility without any hint of a rigorous proof; it is a crackpot paper.
 
  • #41
Hurkyl
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Your illogical logic resorting to insults
If you believe I have insulted you, then you should use the 'report post' feature to make the other mentors (and the administration) aware of my behavior. Assuming you're serious, I'm not really sure what prompted your opinion -- was it the phrase 'appeal to ignorance'? That wasn't an insult: I am using it in its technical meaning describing a class of formal fallacies resembling that of justifying a position on the basis that one is unaware of evidence to the contrary.

Incidentally, there was another error I failed to point out:
Zeno uses our logic of motion and space to define a halfway point that will always be between our object and the finish line
He only demonstrates such a halfway point exists when the object is not yet at the finish line.
 
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  • #42
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The segments that the line is divided into. If we have a line of length D and we divide it into an infinite amount of sections then each section would be the width of D/(infinite)
Zenoman,

Here is something to think about from your original arguement:

I'd argue that since there are an infinite amount of points in a line segment, if you could divide a line segment into an infinite amount you wouldn't end up with points! And as Euclid said, a point is that which has no width. But you are saying it has a width of D/(infinite). How is this any different from (D+10)/(infinite)?

The problem really is you are trying to treat infinity as a number, and it is a concept, not a number.
 
  • #43
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Also I have feel I have a much deeper understanding of the paradox due to Hurkyls and RandallB's lively debate! Keep it up guys!
 

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