Let’s say they never will meet. Are both signs then true?
That’s all good and fine, but that’s not my example. Do you see a logical problem with the signs in my example?
Interesting point, but I think the accepted definition of an object here is something that has mass.
Otherwise, that’s like saying “Picture an unstoppable object made of photons, and an immovable object made of gravitons…” Huh?
Exactly. That’s why there’s no real answer besides the one we know to be: The question, while on the surface is interesting, is ultimately meaningless.
this has quickly become a logic problem and not a science problem, which is starting to twist the constraints established in the OP. However, i don’t think anyone really knows what we’re arguing anyway - a physics problem or a logic problem, so… i guess have at it.
the strong-man analogy is flawed though. the question isn’t about the two meeting. the question necessitates the two meeting. the question isn’t if the signs are flawed but rather can he lift her? once you ask that, the logic is circular and one must be false.
That’s precisely the point. One of the signs must be false. Regardless of whether they ever meet, both can’t possibly be true. The problem isn’t with the science, it’s with mutually exclusive definitions.
As I said, in the post you quoted, there is no contradiction if it’s stipulated they will never meet.
Why must they meet? If, by construction, the man and woman (or ball and pin) will never meet, then it is not logical to ask about their meeting.
Yes I agree the signs in your example are not logically consistent. If the OP was “What happens when a force that can move any object acts on an object that cannot be moved?”, I would agree with you. I am merely stating that there is a difference between an unstoppable object and an irresistible force, and that a logical framework can be proffered that could contain both an unmovable object and an unstoppable one and still be consistent.
The problem is you are thinking that objects have to be solid things that you can touch. But solids aren’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?
So if a kid approaches you at your circus and notes that each sign contradicts the other and asks which one is correct, your response is that they’re both correct so long as they each stay at opposite ends of the midway? The problem isn’t just what happens when they meet, it’s with the descriptions. Each description is worded so as to contradict the other, and both cannot be true.
Nitpick: bouncing would change its velocity, since it includes both speed and direction.
Both cannot be true, if they could interact with each other. But unless you can prove that that hypothetical is always satisfied, you cannot assume it.
If we know it is impossible for them to meet, then there’s no contradiction because it’s nonsensical to ask “what happens when the Strong Man tries to lift the Heavy Woman?”
If you want to appeal to the real world and say it’s silly to say the could never meet, that’s fine. But then you need to add an axiom that “all objects/forces can potentially interact”. Once you include that axiom, then it is logically contradictory to have both the Strong Man and Heavy Woman. But you need that axiom.
The descriptions I’ve given in the signs don’t make that distinction. Each flatly states that the other is false. The Strong Man’s sign doesn’t claim “the Strong Man can lift any person in the world so long as he doesn’t try to lift the Heavy Lady,” they say he is capable of lifting any person in the world, bar none. If there is one person in the world he is incapable of lifting his sign is incorrect, and the Heavy Lady’s sign makes exactly that claim. Even if they never, ever meet, their descriptions are mutually incompatable and logically irreconcilable.
Except we know that it is impossible for them to meet. It’s a fact of this scenario. “Any person in the world” has been defined to exclude the other circus performer. So the signs do not contradict each other.
Both are universal, unqualified claims. Any person in the world means exactly that, or the claim is meaningless. Let’s make the example a little clearer: the Strong Man’s sign explicitly says that he is capable of lifting any person in the world, including the Heavy Lady. The Heavy Lady’s sign says no person in the world is capable of lifting her, including the Strong Man. One must be false. If you’re saying both can be true so long as the rules of nature mandate that they never meet, you’re basically arguing that both can’t exist in the same universe, which was exactly the point all along.
So, what would happen if The Juggernaut ran head on into Superman?
It’s illogical to claim “any person” includes both the Strong Man and Heavy Lady when you’ve specified that they can never meet. “Any person” must implicitly mean “any possible person” or else it is logically meaningless. Would you also accept that “any person” includes people that don’t actually exist? Can the Strong Man lift Santa Claus? Can Santa Claus lift the Heavy Lady? Those are as nonsensical as “can the Strong Man lift the Heavy Lady?”
“Any” must have a precise meaning, and in this scenario, we’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 “the Strong Man can lift any person” and “the Heavy Lady cannot be lifted by any person”.
The rules of nature do not change whether something is logical or not–that is decided from first principles.
I agree - imposing the non-meeting condition is just rendering the definitions completely trivial. Any force could then be considered an unstoppable force, and any object could be considered immovable.
There’s nothing that says the Unstoppable force can’t be deflected rather than absorbed by the Immovable object. The Force keeps moving and the Object stays still. More likely, one of the two would turn out to be as immovable/unstoppable as advertised.
But only, it seems to me, by stipulating non-interaction, which is the same thing as having the body builder never meet the heavy lady.
That’s precisely the point. If I throw the bowling ball out into space, it’s an unstoppable bowling ball as long as I stipulate it doesn’t hit anything. Except, of course, what I’ve implicitly done is defining a universe in which there is nothing to stop the bowling ball, thus making the bowling ball unstoppable. The same goes for the bowling ball orbiting the immovable pin.
Until I saw this I was going to suggest the option that the unstoppable force bounces, retaining speed byt changing direction - which certainly isn’t stopping, but also isn’t this new definition of immoveable.
The next option is that they pass through each other - either noninteractively, or with the unstoppable object becoming a cricket-ball shaped cloud of stoppable powder having been thorougly perforated by the particles of the immobile object. Of course, this only works if none of the composite particles directly impacts, which would then be exactly the same problem at a submolecular scale. (The noninteractive collision would still work of course.)
A third option is that the immovable object is annihilated - utterly vanishing from existence in a puff of logic, as it were. You can’t do that to the unstoppable object because annihilating it would arguably count as stopping it, but the immobile object doesn’t have that problem, as long as it vanishes without moving.
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: