# Immoveable V Unstoppable **URL:** \ **Category:** Great Debates\ **Created:** [November 24, 2008, 1:02pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238 "2008-11-24T13:02:04Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [November 25, 2008, 12:57am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/81 "2008-11-25T00:57:50Z")
> [@CalMeacham](#): > > In Greek Mythology, this was the same problem as Laelaps the hound (who caught evetrything it chased) and the Teumassian Vixen (who always escaped). Zeus solved the problem by turning them intostone, or into constellations, so that the resolution never occurred: > > [Teumessian fox - Wikipedia](http://en.wikipedia.org/wiki/Teumessian_fox) What a cool story. šŸ™‚ So I guess the answer is divine intervention. šŸ˜ƒ ---
**Author:** ![begbert2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/begbert2/32/3357_2.png) [@begbert2](https://boards.straightdope.com/u/begbert2)\ **Post date:** [November 25, 2008, 1:05am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/82 "2008-11-25T01:05:37Z")
> [@Pleonast](#): > > Itā€™s illogical to claim ā€œany personā€ includes both the Strong Man and Heavy Lady when youā€™ve specified that they can never meet. ā€œAny personā€ must implicitly mean ā€œany possible personā€ or else it is logically meaningless. Would you also accept that ā€œany personā€ includes people that donā€™t actually exist? Can the Strong Man lift Santa Claus? Can Santa Claus lift the Heavy Lady? Those are as nonsensical as ā€œcan the Strong Man lift the Heavy Lady?ā€ You are moving the goalposts. Persons who do not exist can be reasonably argued not to be people, and thus can be excepted. They will never meet" is not a reasonable restriction, and so neither of their statements is nonsensical. Theyā€™re if statements that explicitly describe hypotheticals; whether any given hypothetical occurs is irrelevent to their truth, as are any conditions not referenced by the hypothetical. > [@Pleonast](#): > > ā€œAnyā€ must have a precise meaning, and in this scenario, weā€™ve stipulated that it does not include the performers.In that case, both signs are false, because we cannot say anything meaningful about their meeting, since we have defined their meeting as impossible. But the it would still be true that ā€œthe Strong Man can lift any personā€ and ā€œthe Heavy Lady cannot be lifted by any personā€.The rules of nature do not change whether something is logical or notā€“that is decided from first principles. ā€œweā€™ve stipulatedā€? Nonsense. In real logic, statements mean what they say, with no funny-business about re-defining words. The definitions (including ā€œanyā€, as normal people use it)explicitly _include_ the performers. If they contradict, which they do, itā€™s because one of the signs is false. Logically, one of the signs must be true, and one must be false. Period. ---
**Author:** ![Omegaman](https://avatars.discourse-cdn.com/v4/letter/o/e480ec/32.png) [@Omegaman](https://boards.straightdope.com/u/Omegaman)\ **Post date:** [November 25, 2008, 1:35am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/83 "2008-11-25T01:35:36Z")
> [@chowder](#): > > ETA: Iā€™m starting to wish Iā€™d never asked As well you should. All I can think of is bouncer in bar. He thinks heā€™s immovable, I know Iā€™m unstoppable. ---
**Author:** ![laughingboy](https://avatars.discourse-cdn.com/v4/letter/l/9f8e36/32.png) [@laughingboy](https://boards.straightdope.com/u/laughingboy)\ **Post date:** [November 25, 2008, 1:37am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/84 "2008-11-25T01:37:19Z")
If an invisible pink unicorn with infinitely sharp teeth is stranded in an impossibly large field of unchewable clear grass, will it starve to life? ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [November 25, 2008, 1:52am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/85 "2008-11-25T01:52:34Z")
> [@laughingboy](#): > > If an invisible pink unicorn with infinitely sharp teeth is stranded in an impossibly large field of unchewable clear grass, will it starve to life? Depends. Define ā€œpink.ā€ ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [November 25, 2008, 2:18am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/86 "2008-11-25T02:18:07Z")
> [@Strassia](#): > > The problem is you are thinking that objects have to be solid things that you can touch. But solids arenā€™t(really solid, that is). The reason our fingers do not pass through our keyboards is that there is a force that repels them (electromagnetic). What we call mass is merely the property of exerting gravity. I contend that you can have an object made of photons. A laser beam is an object made of coherent photons traveling together at the speed of light. It has momentum, energy and shape. What about this disqualifies it as an object? I understand how solid matter works, and thatā€™s not what Iā€™m saying. I am talking about mass, because inertia is a big part of the equation here. Youā€™re calling a laser beam an object, and thatā€™s fine, as it can fit the definition of ā€œobjectā€ ā€“ I donā€™t want to argue over semantics. But, I think gravity and mass are relevant to the OP. I think itā€™s clear the OP was talking about solid objects and not some exotic flavor of particles (which in your original description seems non-existent). If youā€™re saying the UO and the IO are laser beams, or even a swarm of neutrinos then fine, they pass right by each other. But I think itā€™s kind of missing the point. But, whatever. Iā€™m kind of bored now. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [November 25, 2008, 4:51am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/87 "2008-11-25T04:51:23Z")
Sorry, Pleonast, but your attempt to resolve this paradox is laughable. To use the example Iā€™ve used before, imagine that there are two objects. The first one is bigger than any other object in the universe. The second one is also bigger than any other object in the universe. Which one is bigger? If you say the first object, Iā€™ll point out that the second object is bigger than any other object in the universe so it must be bigger than the first object. If you say the second object is bigger, Iā€™ll say that the first object, by definition, must be bigger than the second object. Itā€™s a logical paradox which proves the premise is impossible: you canā€™t have more than one biggest object in the universe. But trying to claim that both objects are bigger than the other one as long as they donā€™t meet is ridiculous. They canā€™t both be bigger than each other. ---
**Author:** ![pancakes3](https://avatars.discourse-cdn.com/v4/letter/p/ba9def/32.png) [@pancakes3](https://boards.straightdope.com/u/pancakes3)\ **Post date:** [November 25, 2008, 5:03am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/88 "2008-11-25T05:03:24Z")
1 - the man and the woman must meet because the question asks what happens when an unstoppable force meets an immovable object, at least thatā€™s the phrasing madden uses to describe running backs and linebackers. 2 - the fact that the objects exist massless or not, is good enough. remember that according to einstein, mass and energy are one and the same. momentum for mass is (m\*v), for the massless, (planckā€™s constat \* wavelength). 3 - the fact that the velocity changes after bouncing is irrelevant since the object doesnā€™t ā€œstopā€ 4 - i think weā€™ve exhausted all avenues of reasonable possibilities of what happens and have come to 3 possible outcomes: a - it bounces off b - it passes through like light through a window c - the reason for the immovable object being immovable is its infinite mass, in which case it stretches space-time so much that the unstoppable object will not be able to reach the immovable object. yeah? ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [November 25, 2008, 7:54am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/89 "2008-11-25T07:54:04Z")
Iā€™m going for **pancakes3**. I canā€™t see any other way other than his option ā€œaā€. Although I did say that the UO moves at always the same speed I did not say that speed couldnā€™t be reduced by impact with IO ---
**Author:** ![Hap\_Shaughnessy](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Hap\_Shaughnessy](https://boards.straightdope.com/u/Hap_Shaughnessy)\ **Post date:** [November 25, 2008, 8:44am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/90 "2008-11-25T08:44:17Z")
The unstoppable force is the whole of the universe. The immoveable object is the absolute boundary of the whole of the universe. The two rebound off each other in an infinite cosmic resonance. /Have not read the whole thread, sorry if this a repeat of a previous answer. ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [November 25, 2008, 9:22am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/91 "2008-11-25T09:22:00Z")
> [@Hap\_Shaughnessy](#): > > The unstoppable force is the whole of the universe. The immoveable object is the absolute boundary of the whole of the universe. The two rebound off each other in an infinite cosmic resonance. > > /Have not read the whole thread, sorry if this a repeat of a previous answer. Both IO and UO are the size of cricket or baseballs ---
**Author:** ![Hap\_Shaughnessy](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Hap\_Shaughnessy](https://boards.straightdope.com/u/Hap_Shaughnessy)\ **Post date:** [November 25, 2008, 10:41am UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/92 "2008-11-25T10:41:07Z")
> [@chowder](#): > > Both IO and UO are the size of cricket or baseballs Hey, maybe you are right. So what? And maybe my wild-ass guess was right. Again, so what? Either way, I donā€™t know. So what? So? What? ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 25, 2008, 3:53pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/93 "2008-11-25T15:53:29Z")
> [@Little\_Nemo](#): > > To use the example Iā€™ve used before, imagine that there are two objects. The first one is bigger than any other object in the universe. The second one is also bigger than any other object in the universe. Which one is bigger? > > If you say the first object, Iā€™ll point out that the second object is bigger than any other object in the universe so it must be bigger than the first object. If you say the second object is bigger, Iā€™ll say that the first object, by definition, must be bigger than the second object. Itā€™s a logical paradox which proves the premise is impossible: you canā€™t have more than one biggest object in the universe. Yeah, I agree with this. But itā€™s a different problem then the unstoppable force and immovable object. > [@begbert2](#): > > You are moving the goalposts. No, Iā€™m not. It has been claimed that an UF and IO cannot logically coexist. To disprove that claim, we only need to find one logically consistent counter example. To prove the claim, we must show that there can be no logically consistent scenarios in which the UF and IO coexist. (Yes, that is proving a negative, so it will be difficult.) I provided a counter-example with an immovable pin and unstoppable bowling ball. That has yet to be shown inconsistent. The circus scenario was presented and is under discussion. > [@](#): > > Persons who do not exist can be reasonably argued not to be people, and thus can be excepted. Itā€™s not logical to exclude some impossibilities and not others from the set of ā€œany personā€. > [@](#): > > ā€œThey will never meetā€ is not a reasonable restriction, and so neither of their statements is nonsensical. Why is it not reasonable? The circus scenario has three premises:1. A Strong Man who can lift any person. 2. A Heavy Lady who cannot be lifted by any person. 3. It is impossible for the Strong Man and Heavy Lady to interact. Following the rules logic, you may not deny any of the premises. If you prefer to remove one of the premises, thatā€™s fine, but then itā€™s a different scenario. > [@](#): > > ā€œweā€™ve stipulatedā€? Nonsense. In real logic, statements mean what they say, with no funny-business about re-defining words. The definitions (including ā€œanyā€, as normal people use it)explicitly _include_ the performers. If they contradict, which they do, itā€™s because one of the signs is false. No, logic means using the definitions and premises given by the problem. Appealing to common sense or the real world is not allowed. If ā€œanyā€ can include impossible members, then no statement with ā€œanyā€ can be logically valid. ---
**Author:** ![Hazle\_Weatherfield](https://avatars.discourse-cdn.com/v4/letter/h/e9bcb4/32.png) [@Hazle\_Weatherfield](https://boards.straightdope.com/u/Hazle_Weatherfield)\ **Post date:** [November 25, 2008, 3:58pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/94 "2008-11-25T15:58:15Z")
> [@chowder](#): > > **And this you see, is why Der Trihs** \*\* is not the fool lots of people seem to think he is.\*\* > > Heā€™s answered my question succinctly and whatā€™s more his answer makes perfect sense, to me anyway And he no longer beats his wife. šŸ˜› ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [November 25, 2008, 5:21pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/95 "2008-11-25T17:21:09Z")
So anyway: Hurtling through space is this _very_ large lady who says that no man can lift her. Directly in her path is this _very_ strong bloke who says that he can lift any person in existence What hapā€¦oh never mind ---
**Author:** ![pancakes3](https://avatars.discourse-cdn.com/v4/letter/p/ba9def/32.png) [@pancakes3](https://boards.straightdope.com/u/pancakes3)\ **Post date:** [November 25, 2008, 5:46pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/96 "2008-11-25T17:46:31Z")
the circus scenario is indeed a different scenario because if youā€™re equating the strongman to the UO, and the hefty lady to the IO, then the very premise of this thread necessitates the two to interact. The question isnā€™t ā€œcan an IO and a UO exist simultaneously?ā€ but rather ā€œWhat happens when an IO meets an UO?ā€ which is already assuming the existence of the two. My proposal for the strong man, hefty lady scenario is relativistic. The strong man when grabbing the hefty lady literally pushes himself into a hole the ground, since if sheā€™s pushing down at infinite force, and heā€™s pushing up with infinite force, to balance out the free body diagram, he derives his upward lifting force with his feet pushing down on the ground and the ground pushing back. Now since the ground isnā€™t capable of responding with an infinite force, it gives way. Thus the strong man experiences a change in position, which would suggest he lifted the woman, and the woman having not experience movement can claim she still hasnā€™t been lifted. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [November 25, 2008, 5:48pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/97 "2008-11-25T17:48:54Z")
> [@](#): > > Yeah, I agree with this. But itā€™s a different problem then the unstoppable force and immovable object. No. Itā€™s the same thing. Youā€™re taking an absolute quality and treating it as a relative quality. Being an immoveable object is an absolute quality - it says that there is no possible force that can move the object. But the unstoppable force is such a force. If an unstoppable force can exist in the universe, then there is a possible force in the universe that can more the immoveable object - so itā€™s not truly immoveable. And vice-versa. Your contention is the equivalent of claiming that anyone who hasnā€™t died yet can be defined as being immortal. Somebody who hasnā€™t died yet is not the same as somebody who cannot die. And something that hasnā€™t been moved yet is not the same as something that cannot be moved. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 25, 2008, 6:29pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/98 "2008-11-25T18:29:52Z")
> [@Little\_Nemo](#): > > Being an immoveable object is an absolute quality - it says that there is no possible force that can move the object. Precisely. And in my bowling pin/ball example, there is no possible force that can move the pin. So, logic forces us to accept that the pin is immovable. > [@](#): > > But the unstoppable force is such a force. If an unstoppable force can exist in the universe, then there is a possible force in the universe that can more the immoveable object - so itā€™s not truly immoveable. And vice-versa. This is only a problem if it is possible for the posited UF to interact with the IO. In my example, it is impossible for the ball to interact with the pin. And there are no possible objects which can stop the ball, since it is not possible for the pin to stop the ball. So logic forces us to accept that the ball is unstoppable. > [@](#): > > Your contention is the equivalent of claiming that anyone who hasnā€™t died yet can be defined as being immortal. No, my contention is equivalent to claiming that someone who can never die is immortal. ā€œNeverā€ is different than ā€œhas not yetā€. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [November 25, 2008, 7:08pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/99 "2008-11-25T19:08:03Z")
> [@Pleonast](#): > > In my example, it is impossible for the ball to interact with the pin. And there are no possible objects which can stop the ball, since it is not possible for the pin to stop the ball. So logic forces us to accept that the ball is unstoppable. But that means that both unstoppability and immovability are merely equivalent to non-interacting, so that every non-interacting object would be both unstoppable and immovable ā€“ think of a ball of stuff, call it A, linearly moving through empty space. Since thereā€™s nothing that could stop it, by your definition it would be considered unstoppable (and in a comoving reference frame, immovable). Now I teleport myself in there, and catch the ball ā€“ obviously, then itā€™s not unstoppable any more. True, I have violated the non-interacting condition, but letā€™s look at this other ball, call it B, also moving linearly through empty space. Again, I try my teleport catch trick. Only this time, I find I cannot catch it ā€“ in fact, using precision measurement, I find out that no amount of force I exert imparts any acceleration unto the object, and, since even a tiny force would impart a small acceleration on any movable object, correctly conclude that this object must be immovable/unstoppable. Both balls A and B would be, according to your definition, considered unstoppable, yet there is quite clearly a difference in their unstoppability; to me, this can only mean that ball B is the one that is truly unstoppable, and ball A is, well, call it virtually unstoppable (i.e. unstoppable until something stops it). And in that vein, truly unstoppable and truly immovable objects are mutually inconsistent, whether or not they ever interact. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 25, 2008, 7:23pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/100 "2008-11-25T19:23:06Z")
You have three scenarios:A1: "think of a ball of stuff, call it A, linearly moving through empty space. Since thereā€™s nothing that could stop it, by your definition it would be considered unstoppable"We agree, it is unstoppable.A2: "Now I teleport myself in there, and catch the ball ā€“ obviously, then itā€™s not unstoppable any more."We agree, it is stoppable. But this is a different scenario than A1. In A1, ā€œthereā€™s nothing that could stop itā€. In A2, there is. Different premises result in different logical conclusions.B: "letā€™s look at this other ball, call it B, also moving linearly through empty space. Again, I try my teleport catch trick. Only this time, I find I cannot catch it"This is similar to A1, in that there is nothing that could stop the ball. So itā€™s unstoppable. [Previous page](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238.md?page=4) [Next page](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238.md?page=6)