World's best suggested paradox

[NeutralDrow]

How long will it take you to cross a crosswalk if with each step, you cut the distance you walked with the prior step by half?

You'll take the limit as x approaches the distance of the crosswalk.

Sounds like something a calculus teacher would use to introduce the concept of limits (or whatever it's called in english, lim when x nears zero and whatnot)

...ninja'd, shoot.

A man walks up to you and says "I'm a compulsive liar", can you trust him?

No.

He just told you he lies a lot.

What happens when the unstoppable force hits the immovable object?

The unstoppable force technically wins. The result is a black hole.

The mistake is in assuming that the unstoppable force is linear.

If you assume God must follow the laws of physics, then he cannot create an object so big he cannot lift it. It costs far, far more energy to create something (mc^2) than to move it (mgh). Unless he consumes every bit of usable energy in the universe creating it. And if God does not follow physics, then all logic goes out the window, and it's not even worth discussing.

Or, as C.S. Lewis put it, the question itself is pure nonsense. If God is omnipotent, by definition that means there is no rock He can't lift. The question is a semantic absurdity, like asking if God can draw a "square circle."

 

[Lavi]

How long will it take you to cross a crosswalk if with each step, you cut the distance you walked with the prior step by half?

That's not a paradox. You will never cross the crosswalk. Time approaches infinity.

 

[Corkydog]

If purple is the combination of Red and Blue... what is Red or Blue the combination of?

Red and Blue aren't combinations of anything, they are two of the three primary colours which combine to give every other colour.

So does that mean that Red and Blue get away with the same excuse that God does in that they create everything but they just existed from the beginning and nothing actually made them? I don't buy that.

The primary colors don't just exist, they are still frequencies of light, caused by energy emmission. You just can't make a primary color from other colors.

 

[Merkavar]

Not a paradox, but...

1+1=1.

You have one pile of dirt here, and one pile of dirt there. You push them together, and you still have one, bigger pile.

you actually have 2 piles of dirt mixed in with each other.

 

[bz316]

"If you have sex with your clone, is it incest or masturbation?"

-Yahtzee

 

[IMakeIce]

How long will it take you to cross a crosswalk if with each step, you cut the distance you walked with the prior step by half?

That's not a paradox. You will never cross the crosswalk. Time approaches infinity.

That's a hairy thing to say...because you _will_ (mathematically proven) cross the sidewalk at infinite time.

It's a question of semantics, perception of time, and other things that could (have, usually are, probably will be) be debated ad nausaeum; but according to the geometric series describing the crosswalk problem, you definitely will reach the other end of the sidewalk (assuming natural death of old age is not a factor).

Series is: 1/2 + 1/4 + 1/8 + .... = 1

 

[V1C3M4N]

How big was the first step???

 

[V1C3M4N]

How long will it take you to cross a crosswalk if with each step, you cut the distance you walked with the prior step by half?

How big is the first step, not really a paradox

 

[sycoesis]

You can't divide by zero. Yes you fucking can. I have two apples, I don't divide by anything so I still have two apples. The mathematicians just don't want to admit defeat.

but if you have them then you divided by 1

if you have 2 apples and divide then by 0 then you have 0 groups of 2 apples and there fore nothing youve now deleted matter and broken the laws of physics

edit ot time traveler goes back in time and invents time travel before the original person

 

[V1C3M4N]

Infinity is a paradox, because nothing can be infinite. The Universe and time are not infinite, even though scientists keep claiming so, I can prove that the Universe and time are is not infinite through three aguments using two methods, one logic, the other physics.

Ask me if you want proof.

Side note, if/when the ice caps melt, sea levels will not rise. Tell that to the hippies.

 

[IMakeIce]

How long will it take you to cross a crosswalk if with each step, you cut the distance you walked with the prior step by half?

How big is the first step, not really a paradox

I think we can assume that it's half the distance of the crosswalk. If you really want to nitpick at things like _that_ and try to take the entire post absolutely face value, then we also either have to assume that he's never stood anywhere but at the edge of the sidewalk, or we have to know the distance he took with the step that _brought_ him to the edge of the sidewalk. It was poorly worded, but I'm sure you can figure out what the intent behind the post was.

As someone has posted before: Dictionary.com says:

par·a·dox   
[par-uh-doks] Show IPA
?noun
1.
a statement or proposition that seems self-contradictory or absurd but in reality expresses a possible truth.
2.
a self-contradictory and false proposition.
3.
any person, thing, or situation exhibiting an apparently contradictory nature.
4.
an opinion or statement contrary to commonly accepted opinion.

By number 3 (or possibly number 4) this problem _is_ a paradox, it's easier to see why if it's worded thus: "Why, if the distance between two objects can be infinitely halved, can anyone reach any object? (Crosswalk scenario here)." It is a situation that is apparently contradictory in nature. People can obviously reach objects any distance from them given time, but the statement is also true, the distance between the person and the object _can_ always be halved (unless the distance is 0).


Edit:

Infinity is a paradox, because nothing can be infinite. The Universe and time are not infinite, even though scientists keep claiming so, I can prove that the Universe and time are is not infinite through three aguments using two methods, one logic, the other physics.

Ask me if you want proof.

Side note, if/when the ice caps melt, sea levels will not rise. Tell that to the hippies.

The number of distinct points between the numbers 1 and 0 _is_ infinite.

Infinity does "exist" and there most certainly are infinite numbers of "things" in this universe. Physical things maybe not, but things in the loosest definition of things yes.

 

[Jewrean]

How long will it take you to cross a crosswalk if with each step, you cut the distance you walked with the prior step by half?

This is actually doable providing your first step is more than 2/3 of the distance.

 

[friedtoast88]

I'm not sure if this is a paradox, but it's still a cool little idea. I just hope I wasn't ninja'd.

A man is convicted of murder and the judge sentences him to death on a Friday night. (He is sentenced on the Friday night.) The judge tells him that he will be executed at noon on one of the days next work week. (Mon-Fri). He also tells the man that the day of his execution will be a surprise to him until the executioner fetches him from his cell. The man goes to his cell in prison and after much thought he realizes that next Friday could not be the day he will die because the judge told him it would be a surprise and if the executioner doesn't come to get him on Thursday at noon then by process of elimination it must be Friday. This would ruin the idea of his death date being a surprise. This brings the possibility of his death being between Monday and Thursday. So by the same logic he rules out each day of the next week. Content in his conclusion he goes to sleep believing that he will not die. Wednesday rolls around and the executioner arrives at the man's cell to kill him. The man is surprised. everything the judge said has come true.

 

[friedtoast88]

whoops
double post
my bad

 

[Laze]

You can't divide by zero. Yes you fucking can. I have two apples, I don't divide by anything so I still have two apples. The mathematicians just don't want to admit defeat.

-snip-

Think of this this way. When you divide by 2 you divide something into 2 equal pieces. When you divide by 1 you divide into one piece. Dividing by zero divides it into zero pieces, or no pieces at all. Therefore, 2 apples divided by 2 will equal 1. 2 apples divided by 1 equals 2. 2 apples divided by zero equals zero apples.

Munch.

Close but actually 2 apples divided by zero equally infinitely many apples. Easy to see by the following:

2/1 = 2
2/0.1 = 20
2/0.01 = 200
...
2/1E-10 = 2E10 (20 billion)
2/0 = infinity (in the limit)

The paradox of motion named 'Achilles And The Tortoise"

In the paradox of Achilles and the Tortoise, Achilles is in a footrace with the tortoise. Achilles allows the tortoise a head start of 100 metres. If we suppose that each racer starts running at some constant speed (one very fast and one very slow), then after some finite time, Achilles will have run 100 metres, bringing him to the tortoise's starting point. During this time, the tortoise has run a much shorter distance, say, 10 metres. It will then take Achilles some further time to run that distance, by which time the tortoise will have advanced farther; and then more time still to reach this third point, while the tortoise moves ahead. Thus, whenever Achilles reaches somewhere the tortoise has been, he still has farther to go. Therefore, because there are an infinite number of points Achilles must reach where the tortoise has already been, he can never overtake the tortoise

The paradox here is basically a false phrasing because it assumes that Achilles and the tortoise are points instead of 3D shapes, which would mean that Achilles can not occupy more than one "point" at once (in reality, we all occupy infinitely points in space by the definition of a point mathematically)

Also, even assuming that Achilles and the turtle are both points - if there are infinitely many points where the tortoise has been, and the tortoise's current location is defined as a point, the tortoise's interval of motion must be of zero (approaching in a limit) size, and so must Achilles', so neither are moving at all in any finite number of steps. So looking at a finite number of steps from either of them is futile because everything is infinities and you need calculus.

It's really a number line problem where instead of moving in intervals of 1 or 0.5 or whatever where there are a finite number of points with than interval between them on a certain segment of the line, the marker moves by an infinitesimal interval approaching zero so there are infinitely many points with that interval between them on ANY nonzero-length segment of the line. But such a point could only move a distance using an infinite number of steps, so the question becomes moot.

Short version: On a normal number line, when a value moves from 1 to 2, it has passed infinitely many points of infinitesimal size because the set of real numbers is infinite (uncountably). So anything that moves in steps of "points" like the claimed tortoise is actually moving zero distance at each step, and there are (in the limit) infinitely many places that they have been even though they're moving zero (in the limit) distance at each step.

 

[Frozen Donkey Wheel2]

Wow. I was just watching the Big Bang Theory, and I have to say...I had no idea that people like that actually existed. Apparently they've all been on the Escapist.

 

[grimsprice]

I always lie.

You lied about lying all the time. But you still lied, QED, you only lie sometimes. Now happens to be one of those times.

 

[Astoria]

Curry's Paradox [http://en.wikipedia.org/wiki/Curry%27s_paradox], a logical paradox that allows you to "prove" any given statement:

If this sentence is true then Santa Claus exists.
If this sentence is true then the sky is green.
If this sentence is true then God exists.
If this sentence is true then God does not exist.

All of those sentences are true. It's great.

I get it ....I think.

OP Umm I read some really good ones a while ago but I cant remember any!

As for the unstoppable force hitting an inmoveable object that can't happen. If a force is truely unstoppable then there is no object it can't move. If an object is truely unmoveable then it can stop any force. So only one can exist.

 

[Laze]

I'm not sure if this is a paradox, but it's still a cool little idea. I just hope I wasn't ninja'd.

A man is convicted of murder and the judge sentences him to death on a Friday night. (He is sentenced on the Friday night.) The judge tells him that he will be executed at noon on one of the days next work week. (Mon-Fri). He also tells the man that the day of his execution will be a surprise to him until the executioner fetches him from his cell. The man goes to his cell in prison and after much thought he realizes that next Friday could not be the day he will die because the judge told him it would be a surprise and if the executioner doesn't come to get him on Thursday at noon then by process of elimination it must be Friday. This would ruin the idea of his death date being a surprise. This brings the possibility of his death being between Monday and Thursday. So by the same logic he rules out each day of the next week. Content in his conclusion he goes to sleep believing that he will not die. Wednesday rolls around and the executioner arrives at the man's cell to kill him. The man is surprised. everything the judge said has come true.

The is a good one. The paradox lies in the question of how the man can be surprised. By the man's logic, he can only be surprised if he is executed on a day such that no future day will bring an execution without surprise. That day doesn't exist but the closest day to it would be Monday. The man has overlooked the fact that because his logic rules out all of the days of the week as possibilities, an execution on ANY day can now surprise him!

 

[Varius]

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