# 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:** 2
**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 24, 2008, 4:46pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/21 "2008-11-24T16:46:14Z")
> [@RaftPeople](#): > > When they collide, they would instantly be converted into a burrito too hot to eat. You just won the thread. Okay… now that we’re in GD (which, is not a Great Debate per se, but is a fun philosophical conundrum) I’ll go ahead. Why does everyone assume that the unstoppable object (UO) is traveling at high velocity? It’s easier to imagine what would happen if the UO were traveling an inch a year. It would eventually contact the immovable object (IO). If they were spheres, the UO would simply roll around the IO, then proceed on its merry way. Even at a higher velocity, I guess the same thing would happen (if we’re saying they’re indestructible? is that the assumption?). Not sure what would happen if they were cubes and hit each other face on. Infinite friction? That’s the problem when we don’t get enough definitions on what kind of physics we’re dealing with here. As said, using GR, they can both be perceived to be the same thing (UO and IO are interchangeable). They both have infinite energy and mass (in essence, they’d both be traveling at C). If such objects collide, you’d get one hell of a bang. ---
**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 24, 2008, 5:19pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/22 "2008-11-24T17:19:07Z")
> [@panache45](#): > > An impossible situation. By definition, the two objects cannot exist in the same universe. Not so. The can exist in the same universe, so long as they never interact. ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [November 24, 2008, 5:25pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/23 "2008-11-24T17:25:31Z")
> [@Der\_Trihs](#): > > It seems to me that if an Unstoppable hit an Immoveable, the particles that compose the Unstoppable would be forced between the unmoving particles that compose the Immovable, and be on their way as Unstoppable monatomic dust. The Unstoppable isn’t **indestructible** after all; just unstoppable; whereas the Immovable IS indestructible, because destruction would require movement. And this you see, is why **Der Trihs** \*\*\*\* is not the fool lots of people seem to think he is. He’s answered my question succinctly and what’s more his answer makes perfect sense, to me anyway ---
**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 24, 2008, 5:26pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/24 "2008-11-24T17:26:16Z")
> [@](#): > > Not so. The can exist in the same universe, so long as they never interact. No. That would be like saying my example of having two biggest objects in the universe would be possible as long as they were never in the same room to be compared. But even if they never were together, one of them is still not quite as big as the other and is actually the second biggest object in the universe. It’s the same with an immoveable and an unstoppable object. Whichever one would stay true to its name if they met is the real one. The other one is just an object that is very difficult to move or stop. ---
**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 24, 2008, 5:47pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/25 "2008-11-24T17:47:42Z")
> [@Little\_Nemo](#): > > It’s the same with an immoveable and an unstoppable object. Whichever one would stay true to its name if they met is the real one. The other one is just an object that is very difficult to move or stop. Underlining added. Your logic agrees with me–you have to use a hypothetical. If that hypothetical cannot be fulfilled, then there is no contradiction. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 24, 2008, 5:54pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/26 "2008-11-24T17:54:43Z")
> [@Absolute](#): > > For the non-scientifically inclined, this is like asking “Who are the characters in Shakespeare’s _Terminator 2_?” Shakespeare never wrote a play called _Terminator 2_ - it doesn’t exist. The question is meaningless. You mean it’s… not to be? ---
**Author:** ![Fish](https://avatars.discourse-cdn.com/v4/letter/f/bc8723/32.png) [@Fish](https://boards.straightdope.com/u/Fish)\ **Post date:** [November 24, 2008, 5:57pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/27 "2008-11-24T17:57:01Z")
Before you can really answer this, we must know: How big is the Unstoppable? Is it huge like a supernova, or tiny like a photon? What does Unstoppable mean? If you define “Unstoppable” as “must always move in the same direction at the same velocity” you’ll get one answer, but if you define “Unstoppable” as “always moves at the same velocity” then Unstoppable could bounce, like light from a mirror. Is “Unstoppable” always necessarily an expression of velocity or can it mean a process? _Gravity_ is Unstoppable, so far as we know, as is Time… What is the nature of the Immovable? When did it become immovable? Was it already moving when it became Immovable? Because then it could be immovable _and_ unstoppable… ---
**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 24, 2008, 5:59pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/28 "2008-11-24T17:59:40Z")
> [@Pleonast](#): > > Underlining added. Your logic agrees with me–you have to use a hypothetical. If that hypothetical cannot be fulfilled, then there is no contradiction. An unstoppable object is only possible if there doesn’t exist anything that could stop it; an immovable object is only possible if there doesn’t exist anything that could move it. If you have both, that means either that the unstoppable object isn’t unstoppable, or that the immovable object isn’t immovable. It’s a contradiction in terms, perfectly independent of whether or not the two ever interact. ---
**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 24, 2008, 6:02pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/29 "2008-11-24T18:02:32Z")
> [@Bryan\_Ekers](#): > > You mean it’s… not to be? Well, let’s not get ahead of ourselves… _no fate but what we make_ and all. Now, someone just needs to invent a time machine and visit Shakespeare… ---
**Author:** ![Strassia](https://avatars.discourse-cdn.com/v4/letter/s/e8c25b/32.png) [@Strassia](https://boards.straightdope.com/u/Strassia)\ **Post date:** [November 24, 2008, 6:03pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/30 "2008-11-24T18:03:26Z")
> [@Little\_Nemo](#): > > No. That would be like saying my example of having two biggest objects in the universe would be possible as long as they were never in the same room to be compared. But even if they never were together, one of them is still not quite as big as the other and is actually the second biggest object in the universe. > > It’s the same with an immoveable and an unstoppable object. Whichever one would stay true to its name if they met is the real one. The other one is just an object that is very difficult to move or stop. I think the point about interacting is key here. Going beyond even what **Der Trihs** said, you can have an unmovable object and and an unstoppable object if they have no force interactions. Imagine particles that have not charge, no mass, and no cross section. They are not affected by gravity, electromagnetic force, or either nuclear force. In the same universe you could have an unmovable object. When they meet, nothing happens. The particles do not move the object, and the object does not stop the particles. There locations may temporarily overlap, but they have no effect on each other. Jonathan ---
**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 24, 2008, 6:06pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/31 "2008-11-24T18:06:14Z")
> [@Half\_Man\_Half\_Wit](#): > > If you have both, that means either that the unstoppable object isn’t unstoppable, or that the immovable object isn’t immovable. Or, a third option: that they never meet. Consider this scenario: there is an immovable bowling pin. Around it orbits an unstoppable bowling ball. It moves at a fixed distance and speed from the pin. No logical contradiction. ---
**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 24, 2008, 6:15pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/32 "2008-11-24T18:15:40Z")
Let’s start with what we know. Movable objects are, by definition, objects that can be moved by forces. Since there’s no such thing as an unstoppable force, it follows that movable objects can be moved by stoppable forces. Let M = An object is moveable Let S = The force that moves it is stoppable. We have established that M implies S. The contrapositive must also hold: Not S implies Not M. Thereforce, given an unstoppable force we conclude that it will move an immovable object. It’s simple logic. 😉 ---
**Author:** ![pravnik](https://avatars.discourse-cdn.com/v4/letter/p/8edcca/32.png) [@pravnik](https://boards.straightdope.com/u/pravnik)\ **Post date:** [November 24, 2008, 6:15pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/33 "2008-11-24T18:15:48Z")
Yes, it’s a logical contradiction. The existence of an immovable object logically negates the existence of an unstoppable force, and vice versa. You can have one or neither, but not both. It’s not that they can never meet, they can’t both _exist._ It’s a semantic conclusion, not a scientific one. ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [November 24, 2008, 6:22pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/34 "2008-11-24T18:22:15Z")
> [@Fish](#): > > Before you can really answer this, we must know: > > How big is the Unstoppable? Is it huge like a supernova, or tiny like a photon? What does Unstoppable mean? If you define “Unstoppable” as “must always move in the same direction at the same velocity” you’ll get one answer, but if you define “Unstoppable” as “always moves at the same velocity” then Unstoppable could bounce, like light from a mirror. Is “Unstoppable” always necessarily an expression of velocity or can it mean a process? _Gravity_ is Unstoppable, so far as we know, as is Time… > > What is the nature of the Immovable? When did it become immovable? Was it already moving when it became Immovable? Because then it could be immovable _and_ unstoppable… Well lemme think: How big? I guess about the size of a cricket ball or baseball…take your pick Unstoppable means it’s hurtling through space at a great rate of knots, always in the same direction and always at the same speed. Immovable means just that and it was never moving it just appeared at the same time as the unstoppable thingy began its cosmic hurtling. Oh and they are both the same size ---
**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 24, 2008, 6:22pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/35 "2008-11-24T18:22:35Z")
Or, it’s that they’re both the _same thing,_ only viewed from different relative frames of reference. Nothing can be said to be universally, objectively _standing still._ Unless the UO is undergoing acceleration, they both can be said to be equals. ---
**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 24, 2008, 6:23pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/36 "2008-11-24T18:23:54Z")
> [@Pleonast](#): > > Or, a third option: that they never meet. > > Consider this scenario: there is an immovable bowling pin. Around it orbits an unstoppable bowling ball. It moves at a fixed distance and speed from the pin. No logical contradiction. On what grounds would you decide the unstoppability of the bowling ball (or equivalently the immovability of the pin)? Both assertions are logically undecidable in your example, as long as there exists something with which both are not allowed to 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 24, 2008, 6:29pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/37 "2008-11-24T18:29:17Z")
> [@pravnik](#): > > Yes, it’s a logical contradiction. The existence of an immovable object logically negates the existence of an unstoppable force, and vice versa. You can have one or neither, but not both. It’s not that they can never meet, they can’t both _exist._ It’s a semantic conclusion, not a scientific one. You need to show that an immovable object and unstoppable force must _necessarily_ meet. Can you even show how my bowling pin and ball example (merely one example of both existing) is logically contradictory? > [@Half\_Man\_Half\_Wit](#): > > On what grounds would you decide the unstoppability of the bowling ball (or equivalently the immovability of the pin)? Both assertions are logically undecidable in your example, as long as there exists something with which both are not allowed to interact. The typical way: with ping pong paddles. If you try to paddle the pin, it won’t move. It’s immovable. If you hold the paddle in front of the ball, the ball smashes through. It’s unstoppable. ---
**Author:** ![pravnik](https://avatars.discourse-cdn.com/v4/letter/p/8edcca/32.png) [@pravnik](https://boards.straightdope.com/u/pravnik)\ **Post date:** [November 24, 2008, 6:33pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/38 "2008-11-24T18:33:46Z")
> [@Pleonast](#): > > You need to show that an immovable object and unstoppable force must _necessarily_ meet. > > Can you even show how my bowling pin and ball example (merely one example of both existing) is logically contradictory? Yes. If an immovable force exists, there is no force in the universe it cannot stop. If an unstoppable force exists, there is no object in the universe it cannot move. Regardless of whether they meet, they can’t both exist. ---
**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 24, 2008, 6:39pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/39 "2008-11-24T18:39:00Z")
> [@pravnik](#): > > Yes. If an immovable force exists, there is no force in the universe it cannot stop. If an unstoppable force exists, there is no object in the universe it cannot move. Regardless of whether they meet, they can’t both exist. Can you connect the dots a little more explicitly? Because it seems to me that your proof by contradiction will require that the immovable object and unstoppable force have the possibility of interacting. Perhaps there’s another way to show they can’t both exist that I’m not discerning. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [November 24, 2008, 6:39pm UTC](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238/40 "2008-11-24T18:39:19Z")
> [@chowder](#): > > Supposing an unstoppable object hurtling through space was to hit an immovable object also in space. Both objects so described cannot exist in the same universe. [Previous page](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238.md?page=1) [Next page](https://boards.straightdope.com/t/immoveable-v-unstoppable/474238.md?page=3)