Terminator Time Travel

In the Terminator films, Skynet, a computer program that controls nearly the whole world in the future, sends a machine to the past in order to kill John Connor, the future leader of the human resistance, at different points of his life: once before he is conceived (by killing his mother, Sarah Connor). In The Terminator, the machines send the T-101 and the humans send Kyle Reese: the first will give the people in the past the necessary components that will end up starting the Skynet project, and Kyle will be John Connor's father (that is, if the time travel hadn't happened then Skynet wouldn't have been created and John Connor wouldn't have been born).

A predestination paradox (also called causal loop, causality loop, and (less frequently) closed loop or closed time loop) is a paradox of time travel. It exists when a time traveler is caught in a loop of events that "predestines" or "predates" them to travel back in time. Because of the possibility of influencing the past while time traveling, one way of explaining why history does not change is by saying that whatever has happened must happen. A time traveler attempting to alter the past in this model, intentionally or not, would only be fulfilling their role in creating history as we know it, not changing it. Or that the time-traveler's personal knowledge of history already includes their future travels to their own experience of the past.

Terminator 2: Judgment Day, commonly abbreviated as T2, is set ten years after the events of The Terminator, it follows Sarah Connor, her 10-year-old son John, and a reprogrammed Terminator from the future as they defend themselves from a T-1000 and attempt to prevent Judgment Day, a future event in which machines will begin to exterminate humanity. The surviving arm and CPU chip of the original Terminator was analyzed and found that the technology was so advanced, they (humans) would have never invented the technology themselves and was used to create Skynet in the first place, suggesting a second predestination paradox.

Terminator 3: Rise of the Machines does somewhat negate any paradox by showing that the American military have secretly developed the technology independently, suggesting that Skynet was always developed this way and not from the arm of the T-101.

The predestination paradox of the Terminator movies neatly resolve the grandfather paradox by suggesting that time lines inevitably collapse into one sustainable sequence. Unlike a grandfather paradox, where each event negates the other, in a predestination paradox each event is dependent on the other. This avoids the logical pitfalls of the grandfather paradox because once both events occur, the timeline is complete.

An interesting aspect of the "loop" is that the initial events that gave rise to the loop need not be in the final loop. For instance, maybe the original Terminator timeline had no John Connor at all--instead Earth's savior was a man named "Ron Steadman" and initially the Terminators were sent back to kill him. The humans send Kyle Reese back to save Ron, and along the way he impregnates Sarah Connor and she gives birth to John Connor--who now becomes a greater hero than Ron and the target of Skynet's attack in the new timeline. Thus, Kyle Reese is now sent back to save John instead of Ron (who is forgotton) and the 'movie timeline' is born despite its seemingly trigerless series of events.

Another interesting possibility is that somethings have to happen--like the birth of Skynet. Since Skynet can manipulate time, it can send parts of itself back in time and thus will its own creation into a past where it otherwise would not exist. The terrifying implication of this is that if Skynet exists in one timeline it can put itself in all timelines; making it a truly unbeatable opponent. Alternatively, T3 suggests that Skynet must exist not because it sent itself back in time but because its creation is a necessary product of human nature--an invention as inevitable as the wheel. Either way, The Terminator series suggests a creative solution to the grandfather paradox: a 'guided' time travel where some events must or must not occur to create a cohesive timeline.

Welcome to Time Travel Week

Check in everyday this week for new posts on time travel and its perils...

Time Travel 101
Physicists take for granted that if one were to move away from the Earth at relativistic velocities and return, more time would have passed on Earth than for the traveler, so in this sense it is accepted that relativity allows "travel into the future." Any theory which would allow time travel into the past would require that issues of causality be resolved. The classic example of a problem involving causality is the "grandfather paradox."

The grandfather paradox is this: suppose a man traveled back in time and killed his biological grandfather before the latter met the traveler's grandmother. As a result, one of the traveler's parents (and by extension the traveler himself) would never have been conceived. This would imply that he could not have traveled back in time after all, which in turn implies the grandfather would still be alive, and the traveler would have been conceived allowing him to travel back in time and kill his grandfather Thus each possibility seems to imply its own negation a type of logical paradox.

Check back tomorrow for more time travel.

Schrödinger's Cat

This is a follow up to the Double Slit experiment

Schrödinger's cat is a thought experiment devised by Austrian physicist Erwin Schrödinger in 1935. It illustrates what he saw as the problem of quantum mechanics being applied to everyday objects. The thought experiment presents a cat that might be alive or dead, depending on an earlier random event.

Schrödinger wrote: "One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts."

The purpose of the thought experiment is to illustrate an apparent paradox: our intuition says that no observer can be in a mixture of states, yet the cat, it seems from the thought experiment, can be such a mixture. Is the cat required to be an observer, or does its existence in a single well-defined classical state require another external observer?

Invisible Hand

The invisible hand is a metaphor coined by the economist Adam Smith in The Wealth of Nations. In economics, the invisible hand is the term economists use to describe the self-regulating nature of the marketplace. More broadly, it describes any situation where multiple people cooperate solely out of self interest rather than any altruistic motive.

Smith provides an example that illustrates the simplicity of the principle: “It is not from the benevolence of the butcher, the brewer or the baker, that we expect our dinner, but from their regard to their own self interest. We address ourselves, not to their humanity but to their self-love, and never talk to them of our own necessities but of their advantages."

This is an example of a game theory situation known as a "stag hunt." The stag hunt is a close cousin to the Prisoner's Dilemma. Jean-Jacques Rousseau described a situation in which two individuals go out on a hunt. Each can individually choose to hunt a stag or hunt a hare. Each player must choose an action without knowing the choice of the other. If an individual hunts a stag, he must have the cooperation of his partner in order to succeed. An individual can get a hare by himself, but a hare is worth less than a stag.

In addition to the example suggested by Rousseau, David Hume provides an example of a stag hunts. His addresses two individuals who must row a boat. If both choose to row they can successfully move the boat. However if one doesn't, the other wastes his effort.

The Genius of Stupidity

Consider the origins of everyday items--some of them really make you wonder. Take the cigarette for instance. Millions of people smoke them everyday, it’s a billion dollar industry---but I wonder who was the first guy to look at a tobacco plant and think, “gee, I wonder what would happen if I ripped off some leaves, rolled them into a cylinder then stuck it in my mouth and lit the whole thing on fire. Ahh, I got nothing else to do--let’s give it a whirl.” Who thinks of that? Very rarely in my day do I see an object I’d like to insert into one of my orifices and set on fire. That just doesn’t cross my mind too often. I know three year olds who eat paint that know better than to stick things on fire in their mouth.

And it’s only made stupider by the fact that after taking these tobacco leaves, sticking them in his mouth and lighting them on fire he probably started hacking up a lung and felt sick to his stomach but did it two dozen more times anyway until he thought, “ehh…this isn’t so bad.”

This bring me to my main idea: idiocy seems to get rewarded a helluva lot. For instance the idiot in question who invented the cigarette probably went on to open up Phillip-Morris and become a multi millionaire. Sometimes doing the most boneheaded, stupid thing you can will bring your fame and fortune beyond your wildest belief. It’s the whack-a-mole approach to success.

Take the leaning tower of Piza for instance. You'd think "how to NOT have your tower tilt on its side" would be like the first thing they teach you in architect’s school. But some bonehead slept through class, decided to wing it and made what is probably the world worst tower—which in turn made it the world’s most famous tower.

If you can think of anything boneheaded that made someone rich and/or famous, please post it in the comments.

The Zebra Puzzle

The Setup:

1. There are five houses.
2. The Englishman lives in the red house.
3. The Spaniard owns the dog.
4. Coffee is drunk in the green house.
5. The Ukrainian drinks tea.
6. The green house is immediately to the right of the ivory house.
7. The Old Gold smoker owns snails.
8. Kools are smoked in the yellow house.
9. Milk is drunk in the middle house.
10. The Norwegian lives in the first house.
11. The man who smokes Chesterfields lives in the house next to the man with the fox.
12. Kools are smoked in a house next to the house where the horse is kept.
13. The Lucky Strike smoker drinks orange juice.
14. The Japanese smokes Parliaments.
15. The Norwegian lives next to the blue house.

The Problem: Who drinks water? Who owns the zebra?

• Each of the five houses is painted a different color, and their inhabitants are of different national extractions, own different pets, drink different beverages and smoke different brands of American cigarettes.
• In statement 6, right refers to the reader's right.
• It is possible not only to deduce the answers to the questions but to figure out who lives where, in what color house, keeping what pet, drinking what drink, and smoking what brand of cigarettes.

The Solution:

house	1	2	3	4	5
color	yellow	blue	red	ivory	green
nationality	Norwegian	Ukrainian	Englishman	Spaniard	Japanese
drink	water	tea	milk	orange juice	coffee
smoke	Kools	Chesterfield	Old Gold	Lucky Strike	Parliament
pet	fox	horse	snails	dog	zebra

Water and Wine

The Setup: One has two barrels, one holding wine and the other an equal volume of water. A cup of wine is taken from the wine barrel and added to the water. A cup of the wine/water mixture is then returned to the wine barrel, so that the volumes in the barrels are again equal.

The Problem: which of the two mixtures is purer?

• The problem can be solved without resorting to computation.
• The volume of the cup is irrelevant, as is any stirring of the mixtures.
• Any number of transfers can be made, as long as the volume of liquid in each barrel is the same at the end.

The Solution: The mixtures will be of equal purity. Below is a breakdown of the numbers, presuming 80 liters of fluid per barrel.

Wine Barrel	Action	Water Barrel
80 (all wine)		80 (all water)
	20 (all wine) →
60 (all wine)		100 (80 water, 20 wine)
	← 20 (16 water, 4 wine)
80 (64 wine, 16 water)		80 (64 water, 16 wine)

The easiest way to explain this problem is, that if the volumes of liquid return to the exact same amounts, then, after the transfer of the wine and water, the wine that was transferred to the water has to be the same amount of water that was transferred to the wine.

Ramblings on Evolution

According to evolution, plants and animals develop in ways to allow them to thrive in their given environment. If its cold, you grow fur. If its wet, you develop webbed feet. Nature produces some weird designs. Look at the platypus. Any animal could have a beak or claws or whatever but being a platypus is a whole other thing.

Humans have succeeded based on brains not brawn. However evolutionary speaking, brawn is not a bad strategy. Lions and tigers and bears are all the top of their respective food chain. Brains work, brawn works. Being huge isn’t a bad idea either—no other creatures mess with a whale or elephant. But there are some survival strategies that just plain baffle me: a giraffe is pretty much a horse that said to itself, “if I grow my neck a little longer, I'm gonna be running this jungle.”

Another "curious" evolutionary tactic is the skunk. The skunk is nature’s ultimate hater. Of all the natural defenses you could evolve: claws, spikes, fangs—the skunk has chosen stink. You mess with a skunk, it’ll make you smell bad. What kind of predator is going to be deterred by that? I don’t think a bear or wolf sees a skunk and thinks to itself, “well I haven’t eaten in five days-- but on the other hand, I might go to a club tonight.”

Even some plants have pretty sly stratagies. What do industrial farmers have in common with a bees? Like the bumblebee, both disseminate the genes of one species, a potato instead of a leek, rather than another. And like the bumblebee, they view the plants as here for their benefit. The bumblebee breaks into the flower, finds the nectar, thinks he's making off with the goods and thinks he's getting the better of the deal with the flower. But, in fact, it's the flower that has tricked the bumblebee into doing the work for him, to take his pollen from flower to flower to flower. From the flower's point of view, the bumblebee is this credulous gullible animal. Likewise, we could just be pawns in corn's plot to dominate the globe.