Contact logic not adequate for real life situations

[Ghost Post]

Firstly it should be impossible. Simply because you might spend an hour each night looking at the stars and naming the constellations. If you are no longer on Earth you won't be able to see the constellations.

[mwf]

This is a question of scince. One of the first things I learned in my first physics class was. It is true until you can prove all of some of it wrong. So the question is then. Is there at least one thing that us humans can not explain using math, sceince and physics? If you can find at least one thing then the answer is, no.

[Chuck]

The aliens should just brainwash us into believing everything is normal. That would be easier.

[OcularGold]

Vanyo - what can i say? you can have an electromagnet with no moving parts. its not perpetual, of course, since you need a potential to carry across a current.
http://howstuffworks.lycos.com/electromagnet1.htm

Dave - i think the problem is thus: can you describe, using only words, in perfect detail our world, given an infinite amount of time.

thats it.

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I've seen water. It's water that's all.

[Vanyo]

Of course you can have an electromagnet with no moving parts. But a generator? I.e., use a magnet (which produces a magnetic field) to generate electricity, without moving parts.

[Cie Sharp]

This comment is in regards to the previous argument of how do we describe oxygen and nitrogen to the aliens. This is SOOO simple, and they actually addressed this on an episode of Star Trek: The Next Generation (I forgot the title, though).

Two ships (enterprise, alien who couldnt speak our language) were together in this black hole like place that they couldnt get out of, and the alien ship kept posting to the enterprise a picture of a big sphere being orbited by a much smaller sphere ... And everyone On the Enterprise stupidly thought "Well, that must be their home planet!" but then Data finally figured out that they were posting a picture of a hydrogen atom, and that they wanted the Enterprise to vent hydrogen. So the enterprise vented hydrogen from the warp nacelles, the aliens sent forth another much bigger atom unknown to us, and it made a big explosion, sending both ships out of the black hole!

So if we ever were in this situation, just send the aliens a rough picture of oxygen and nitrogen atoms. They have these pictures in college entry-level chemistry books.

[OcularGold]

of course not, vanyo, as i said before, you need a turning magnet to induce a current, as illustrated here: http://www.creative-science.org.uk/gen1.html

[OcularGold]

Vanyo - tell me how a magnetic field CANT move a charged particle? what the heck is a magnetic field then?

[Ghost Post]

I'm not understanding why we need a magnet for this left-right thing in the first place. I think you're overcomplicating the matter by introducing the magnet. The "right hand rule" is simply function of cross products. Since we already mathematics as a language, vector functions are included in that language. When we build a three dimensional axis system, the unit x vector when crossed with the unit y vector MUST equal a positive z. If you don't get a positive Z with such a cross product then your X and Y axis are simply switched (ask anybody who uses POV-ray). If we describe our physical makeup in terms of co-ordinates or vectors, left and right is a cinch.

Davy

[mwf]

Flip the Y axis and use a "left hand rule" and all the equations still work. Your equation just ends up mirrored about the Y axis. I use this trick a lot at work to mirror data from left to right and back again.

The axis orintaion is only a product of how we chose to see what is positive and negitive.

[Ghost Post]

Using a left hand rule requires the use of a different formula for cross product though. Remember that a cross product formula returns a directional vector. We only invented the RHR to make it easier for us to verify the direction.

[Ghost Post]

Nevermind, I think I follow what you mean now.

[art begotti]

when i first looked at the puzzle i thought... it says it orbits a star with other planets. then the word aliens... could it possibly be that the people are aliens to the country? like they are from russia or bangladesh or something?

[treadmill]

maybe the aliens could fluke it hehehe

[Russian]

WHO said I am an alien?

[WordSmith]

The answer to this one is: "Who cares?"

This is not a "puzzle" by any stretch of the term.

After that last Doomsday fiasco, what a major disappointment!

Phrn't!



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Somewhere, I'm sure, there must be
two logicians who agree. I, however,
don't happen to be one of them.

[Vanyo]

Here's how it works:


The magnetic field exerts a force on an electron in a direction which depends on the direction of motion of the electron.

Suppose I'm standing in a magnetic field with north oriented straight forward. Electrons moving to the right will be deflected upwards, while electrons moving to the left will be deflected downwards. So that tells you left from right if you know which way north is (and hence can tell you which is north if you know right from left).

[This message has been edited by Vanyo (edited 07-02-2001).]

[LoopyDog]

I have a suspicion that we can sort out L/R using the racemic approach. As an aside my two cats are racemic - which is why they'll make wonderful bookends in due course.

My bio-chemistry isn't up to it, but I have a suspicion we could define a RNA chain which would produce dextro or laevo-rotatory outputs. I can't see how else to get close to this problem. Now even if this is a solution, what happens if their galaxy is an anti-matter one? Can we determine this? I think we also need to define North and South and then find out do they have a LH or RH rule. Maybe this would be an answer. Enough speculation ...

[Felonix]

Great. Now, of course, Current is arbitrarily set to flow from the positive terminal to the negative terminal, and both positive and negative distinctions were completely whimsical. So now how do you know they don't see current as flowing the opposite direction and use a differant rule?

[mwf]

The problem with describing right and left is the you have to nail down all 3 axis first. All it takes is 1 axis to be able to be flipped some were in the description and the information can be mirrored. Resulting in wrong handness.

[Vanyo]

Positive and negative electric charge is not a problem if they know about electrons. Or if their chemistry is the same, instruct them how to build a simple battery.

[bobwashere]

This question is not a puzzle where I come from, this is more of a conundrum.

The concept of left is easy. It is the hand in which you hold your spoon.

You jokers are too smart for yer own good.

bob

[William Where]

This is my first posting in the Grey Labyrinth. I'm Spanish, so excuse me if I misspell some words.
Point 1- Left and right trouble. In some posts, have been said that the concept of left and right must be known to make some particles, but I don't think so. The molecules with that "specular" images (sorry, I do not know the word for "isometria". Issometry, I suposse) are not defined by left and right concepts. It's only a way to represent them. That molecules are defined by their physic properties. And the fact that the opposite image of one of them can not been used to build a more complex one, is enough to describe wich is one.
Also, if aliens change the concept of left and right, you will NOT be able to know that, since EVERYTHING will be changed.
2- You can describe the world well enough so you won't difference it from real one. Perhaps you don't know how are the constelations, but if you don't know that, you won't notice the constelations are wrong when you are there.
3- But Human behaviour cannot be described as well. Is not scientific knowledge. It will be as in that famous film "Invasion of the body snatchers" or "body thieves" or something like that.
So I think you will notice people is different. But only people.
Thanks.

William Where

PS: The aliens' world is almost equals to ours. And if the "aliens" are humans from the future? (no related to the question)

[Chuck]

Maybe the aliens CAN keep us from telling the difference. Maybe they already have.

[Zarriar]

This whole idea is similiar to that presented in the movie the the matrix , when the young hacker says How do the machines know what tasty wheat tasted like ? . So maybe it would be easier for the aliens to simulate a reality that you can't differentiate from the real world rather than one that is an actual copy.

Hi William welcome to the GL. Are you talking about diastereoisomers ? If you are I think that they could be used to convey a sense of right and left provided that the alien civilisation operated under the same physical laws as our universe.

[Vanyo]

[Loki]

I can never remember if this is fact or fiction, but what about that "Water goes clockwise down the drain in the northern hemisphere, counterclockwise down the drain in the southern hemisphere" thing? Is that a myth? If not, it seems pretty useful.

[Vanyo]

Myth. I'm sure it's covered on The Straight Dope site, but I'm too lazy to find a link right now.

Besides, even if true, it wouldn't help! You can't tell them north and south, AND you can't tell them clockwise and counterclockwise (it's equivalent to right and left).

[OcularGold]

Not quite, Vanyo - youre misinterpreting the relation between acceleration and velocity.

the direction of the magnetic field and the force DETERMINE the particle's velocity, not the other way around.

im sure youre familiar with centripetal force?

when a mass is rotating around an object.. thing about a sling with a stone...
the stone rotates around the center - the force vector always points towards the center, but the velocity vector is always perpendicular to the force vector!

this is similar to an electron around a wire..

the force is always towards the center (towards the wire), but the electron passes around the wire. since it carries a negative charge, it follows the right-hand rule and moves clockwise.

anyways, lets just assume im wrong, or whatever, and that we just determine left right by using radioactive cobalt at near absolute zero...

lets look at the rest of the problem: is there any way to describe human behavior well enough that if aliens were to contruct what we were to say, we would be able to tell the difference between their humans and those on earth?

if the aliens were made of anti-matter, how can we determine the difference?

[Zarriar]

I live in Australia and I just checked the water going down the sink in our lab and it goes anti-clockwise.

Vanyo. I think what William was getting at is that you can react a chiral compound with a racemic mix to get two diastereoisomers. Diastereoisomers can rotate the plane of plane polarised light in different directions or by different magnitudes and often have slightly different physical properties, e.g melting point, polarity etc that can be used to separate them. In fact that was one of the main ways for separating optical isomers, these days though they tend to use chiral chromatography, I guess because it is more efficient.

[ezmeralda]

I don't have an answer but just thoughts. To recreate a world the aliens wouldn't have to necessarilly build anything-all they have to create is an illusion--and in this case our illusionary world begins with the senses. As long as we sense things as such--the mind cannot know beyond the senses. We already have bionic ears that attach to the hearing mechanism in the brain stem. So if they disconnected our brain from all its senses and created the necessary electrical stimuluses at the sense input terminals on the brain: eyes, ears, taste, etc. That world would be real. They could give us a new virutal body connecting our motor activity to the illusion. It would be quite a feat to do something like that though, and maybe there is something not quite possible. Because in that virtual world they would have to create another "dream free from contradiction" as science so likes to put it. So how do we know we are not in that world right now? Maybe our brains are in some laboratory and everything we think we do is simply a computer generated hologram. Maybe kind of like the movie "Matrix." What really does happen when we die? Its just a different perspective on it, but I apologize for it not being developed to answer anything. But how do I know the world is real?

[ezmeralda]

I missed zarriers comment; I just restated a little. Ya, I agree.

[Ghost Post]

I have read the lecture referred to in the puzzle and the answer is that we humans cannot perfectly describe ourselves in this universe to another life-form, if we have only verbal communication with them.

The problem with our universe is the symmetry of nature. We would have to assume that these aliens are made of matter as we are and it is possible they are comprised of antimatter. If they are antimatter then any phenomenon that can discern symmetry to us, will be the opposite to them.

The example given in the lecture is an isotope of cobalt stuck in a strong magnetic field at a very low temperature to stop thermal oscillations. This isotope when it is lined up in a field with its B vector pointing up, most of the electrons are emitted down. This example can be used to say that our universe is not symmetrical, but the existence of antimatter makes it symmetrical.
I hope that cleared things up.

[Vanyo]

Ocular Gold:

[Ghost Post]

There are two questions:
Could you survive? Well yes. You can describe in clear terms what is needed to survive.

Could you have them recreate the world well enough so you could not tell the difference? The answer is definately no. How would you describe the stock market and other non-linear patterns? There really is no way to explain what it means when your significant other is pissed off. The environment might look the same, smell the same, and even taste the same but it won't act the same.

[Vanyo]

[dave10000]

To address Vanyo's issue, I don't think you need to resolve the left-right thing in order to *survive.* Since both groups will recognize this problem, just tell them to make sure there's pleanty of BOTH types of proteins. That will ensure that you get at least some of the correct ones.

[Sofis]

That won't work - the wrong kind can be harmful. I'm sure you've all heard of the Thalidomide scandal. The drug that was sold was a mix of the two isomers. One of them was perfectly harmless and the acting ingredient, the other caused fetal damage.

[Vanyo]

OK, but they can set up two alternate environments, one left-handed, one right-handed. Have a fork in the path leading to them, with a sign that says "take left path". We should be able to explain to them how to do it so that the left path is the correct path (even though they won't know which path that is).

[Cappuccino]

Dave is right that the answer depends on whether we can extend the Aliens powers to include the infinite. If they were able to replicate our physical, chemical, and other processes, and run an infinite number of scenarios using an infinite number of starting points, one of these would be equivalent to ours. And then in an instant the two worlds would diverge again, but we wouldn't be able to tell which is real and which was fake.

If you don't give them the power of the infinite, I don't think they could even come close. I don't think they could adequately replicate a cow's digestive system or an anchovy population, much less the whole Earth. You can't replicate a complex system by breaking it down in a reductionist way to the nth degree. At some point there are random things that overwhelm reductionist science. Hence chaos theory. If we are presupposing that the Alien magic includes the ability to predict the unpredictable, then that truly is magic.