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.
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.
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…
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.
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.
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.
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.
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.
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.
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?
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.
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.
