Irresistible force paradox

The Irresistible force paradox, also the unstoppable force paradox, is a classic paradox formulated as follows:

:"What happens when an irresistible force meets an immovable object?"

Common responses to this paradox resort to logic and semantics.

*Logic: if such a thing as an irresistible force exists, then no object is immovable, and vice versa. It is logically impossible to have these two entities (a force that cannot be resisted and an object that cannot be moved by any force) in the same universe, unless they are both a result of a "single entity", in which case the immovable object radiates (meets) the irresistable force. Logic maintains that there could only be "one" Immovable Object emmanating the Irresistable Force in the known universe, as the Irresistable Force would move all other objects. This view becomes less of a paradox, and more of a trick question.The Immovable Object can be equated with Space, and the Irresistable Force with Time.

*Semantics: if there is such a thing as an irresistible force, then the phrase "immovable object" is meaningless in that context, and vice versa, and the issue amounts to the same thing as, for example, asking for a triangle that has four sides.

A third response to this paradox employs the humour of exaggeration: "The result would be an indescribable collision!"

This paradox is a form of the omnipotence paradox, but that paradox is most often discussed in the context of God's omnipotence ("Can God create a stone so heavy it cannot be lifted, not even by God Himself?").

The paradox should be understood as an exercise in logic, not as the postulation of a possible reality. According to modern scientific understanding, no force is completely irresistible, and there are no immovable objects and cannot be any, as even a minuscule force will cause a slight acceleration on an object of any mass. An immovable object would have to have infinite inertia, and therefore infinite mass. Such an object would collapse under its own gravity and create a singularity. An unstoppable force would require infinite energy, which does not exist in a finite universe.

An example of this paradox in non-western thought can be found in the origin of the Chinese word for paradox (zh-cpl|c=矛盾|p=máodùn|l=Spear-Shield). This term originates from a story (see the "Kanbun" example) in the 3rd century BC philosophical book "Han Feizi". ["Han Feizei" (韓非子), chapter 36, "Nanyi" (難一 "Collection of Difficulties, No. 1")'.] . In the story, a man was trying to sell a spear and a shield. When asked how good his spear was, he said that his spear could pierce any shield. Then, when asked how good his shield was, he said that it could defend from all spear attacks. Then one person asked him what would happen if he were to take his spear to strike his shield; the seller could not answer. This led to the idiom of "zìxīang máodùn" (自相矛盾), or "self-contradictory."

In popular culture

*The 1955 song "Something's Gotta Give" refers to the paradox in its opening lines: "When an irresistible force, such as you, meets and old, immovable object, like me..." The song was written by Johnny Mercer for the Fred Astaire film "Daddy Long Legs".

*In issue three of the comic "All Star Superman" by Grant Morrison and Frank Quitely, Superman is posed the question "What happens when the unstoppable force meets the immovable object?" He replies that "they surrender."

*The popular Blizzard Entertainment video game World of Warcraft makes reference to this paradox in the form of two in-game items: [http://www.wowhead.com/?item=19323 The Unstoppable Force] is a two-handed mace, whereas [http://www.wowhead.com/?item=19321 The Immovable Object] is a shield, prompting the question, "what would happen if the Unstoppable Force were to hit the Immovable Object?" When this question was posed to one of the designers, he answered with "Chuck Norris dies," another pop culture reference often used in World of Warcraft.
** In comedic parallel, World of Warcraft also features an item called [http://www.wowhead.com/?item=25402 The Stoppable Force] .

*During the broadcast of WrestleMania III in 1987, commentator Gorilla Monsoon associates the paradox with the matchup of Andre the Giant and Hulk Hogan, in what would eventually become one of the most famous moments (and quotes) in professional wrestling history.

*The voice of John Madden uses the line in the Madden video games as commentary during the action.

*The author Iain Banks uses the paradox in his book "Walking on Glass"

*The Suikoden Series features this paradox as its creation myth, "In the beginning there was darkness, then the darkness shed a tear, the tear became a sword and a shield, The shield claimed it could defend against any attack, the sword claimed it could pierce any defense, they began a legendary battle, at the end both sword and shield shattered, the sword became the sky and the shield became the earth, the sparks from their battle became the stars.."

*In the 2008 film, The Dark Knight, The Joker is caught at the end and metaphorically refers to the paradox. He describes their conflict as an unstoppable force meeting an immovable object.

*The 1982 "Knight Rider" episode, "Trust Doesn't Rust" uses this paradox in an attempt to conclude the outcome of a battle between K.I.T.T. and his equally-powerful twin, K.A.R.R.

*After defeating Xaero in the video game Quake III he sometimes exclaims: "At last, the irresistible force has met the immovable object."

*In the fifth case of the Nintendo DS game , prosecutor Miles Edgeworth mentions the story about the spear and shield as the history behind an awards trophy and the Chinese word for "contradiction."

Alternative views

1. An immovable object must be anchored within the zone of physical reality so, if an irresistible force meets it, the object will not move within its relative reality, but the entire reality itself may move.

2. The force will pass through the object, and the object will not move. Who is to say that one or the other is solid, or even made out of materials that can interact with each other?

3. If these two forces actually existed in reality and were to collide it would cause what could be called "infinite potential". Meaning by colliding these two omnipotent forces anything is possible due to the fact that they represent ultimate power.

4. The two will cancel each other out, ceasing to exist.

5. The force continues at with the same magnitude, however diverted. One half going one way, the other half going a separate direction, still having the same force, but moving separate directions.

6. The Irresistable Force emmanates from the Immovable Object. They are one and the same thing. They meet because the Force is radiating from the Object, which also contributes to making it Immovable.

Theories as told by physics students

What happens when an unstoppable force hits an immovable object?

Theory #1- In the case of an unstoppable force colliding with an immovable object, we must imagine that both objects are the same, both are unstoppable and both are immovable, nothing can stop them and nothing can move them, except for each other.

Theory #2- The unstoppable force will pass straight through the immovable object, the unstoppable force remains unstoppable and the immovable object remains immovable.

Theory #3- The unstoppable force combines with the immovable object creating a black hole which is both unstoppable and immovable.

Theory #4- The unstoppable force will ricochet off the immovable object and the unstoppable force still has not been stopped, the immovable object has not been moved.

Theory #5- There will be an eternal struggle between the object and the force, which neither will win. Although if this is the case then the immovable object would have won, as the unstoppable force would in fact be stopped.

Theory #6- The energy from the unstoppable force would transfer to the unmovable object. i.e making the unmovable object become the unstoppable force and vice versa.

Theory #7- You Are Sam Perkins says: As a concept an object that is immoveable has infinite inertia (its resistance to being moved). And as such, mass is the measure of an object's inertia, and if it has infinite inertia, it has infinite mass.

This would mean that to move it, it would require an infinite amount of energy to make it accelerate. This can be seen from the equation:

E=1/2 mv^2

Where m = infinite

And v^2 and 1/2 both multiplied by infinity, or simply infinity, regardless of how fast the object moves.

So if we wish to move the object, which is the same as saying we wish to make the object accelerate, then we need to apply the equation:

F = ma

Where F is the force we need to apply to achieve the required acceleration (in this case any that is not zero). m is the mass of the object and a is the acceleration we wish to gain.

rearranging the equation we get:

a = f/m

Now, assuming an unstoppable force is infinitely large, and we already know out mass is infinitely large, then we can express the above equation as follows:

a = infinity/infinity

Using basic maths principles, we know that anything divided by itself is in fact = 1

so

a = 1

IE: the force pushes the object to accelerate at 1m/s/s

Note: The division between 2 infinities cannot be asserted. The 2 infinities in question are not proved to be the same (i.e. one infinity could be progressing faster than the other. e.g.: 1,10,100,1000 progresses faster than 1,2,3,4,5..). Therefore, dividing infinity by infinity does not in fact = 1, which means a !=1 , but rather "unknown". The only way to assert that "the value of a would be close to 1" is to suppose that the two infinities are "almost" equal.)

The end.

Theory #8- Time & Space: The Irresistable Force emmanates from the Immovable Object. The Irresistable Force would be Time, being irresistable, it would continually push everything onward, nothing would ever be able to turn back, or even turn in a direction toward the Irresistable Force (no time travel in this venue, Einstein). The Immovable Object would be Space, while objects can move around within it, nothing can move space itself (no teleportation if you believe in this theory, sci fi fans).

This leads to other questions as to how Space generates Time, and other interesting questions for all you brilliant philosophers and physicists to ponder on.

References