Quantum Physics 123: Monday 14 November

[ten-and-chips.livejournal.com]

[The Doctor sits on top of his desk, swinging his legs, as the class enters. He's got coffee and tea for all. They'll need it.]

The American cartoonist Walt Kelly once said 'We have met the enemy, and he is us.' This is often used to explain the idea of a predestination paradox, the first of this week's return to the concept of paradox itself.

Simply speaking, a predestination paradox occurs when a person goes back in time to prevent an event, but ends up causing it. This is also known as a causality loop. For example, if someone were to go back in time in order to prevent an assassination, but a series of events led to his or her being the cause OF the assassination--that would be a causality loop. This happens far, far more often than one would think.

Some would say that this sort of paradox proves the existence of fate. Others say that it proves that time itself is more resilient than most believe. The Novikov self-consistency principle is one of the theories that supports this.

In my experience, it is the error of sentient beings themselves that causes this sort of loopage. However, your belief in this area should be the result of your own judgment, whether faith or scepticism.

Any questions?

I'd like a short essay from each of you by Wednesday speculating how you could cause a predestination paradox in your own life by merely trying to change one small event.

Comments

[carter-i-am.livejournal.com]

Sam came into class and got herself a cup of coffee. When she heard the topic of conversation, she closed her eyes briefly, sighed, and wished that she had some kind of alcohol to add to her beverage.

Still, this was the perfect time to address the John Connor problem with someone who might really know how to fix it. "Sir? Is there any way to pinpoint the one event that causes time to loop back in on itself?"

[ten-and-chips.livejournal.com]

[The Doctor considered bringing in whisky, but decided he didn't want to risk his job just for student comfort...even if it would probably help them wrap their brains around the concept. Maybe if he talked to Dean Bristow...]

That's difficult, Ms--Sam. [He scratches the stubble on one cheek--the stubble that Doesn't Seem To Ever Go Away, despite shaving every morning.] Eventually, if the situation is clear-cut enough, the event becomes fairly apparent. However, in a complex scenario, analysis becomes difficult. Some technology can pinpoint the point of divergence, but that belongs only to very highly complex civilisations. Most of the time, one has to do it by hand.

[carter-i-am.livejournal.com]

Sam smiled at the Doctor's use of her first name. She also took a moment before answering to admire the Doctor's oh-so-manly stubble collection.

"But if you can pinpoint several key events that absolutely have to happen for a certain, catastrophic event to take place, can you stop the major event by interfering with one of the lesser events?"

She frowned and sipped at her coffee. "I guess what I mean is--is it enough to stop the smaller causes, or do you have to go after the big, immediate one?"

[ten-and-chips.livejournal.com]

[His brow furrows in thought.] I think it would have to go on a case by case scenario. Sometimes stopping a smaller event would lead to the end of a larger related one. Sometimes not. It's all very relative. Do you have a specific scenario in mind?

[carter-i-am.livejournal.com]

Does she ever. "Say, hypothetically speaking, that you're aware there's an end of the world, apocalypse-type situation headed your way. One of the major players after the apocalypse is a creature of the paradox you've been talking about--his future (and the apocalypse) has to happen so that his past can exist. Is there a way to get around the loss of life without dooming this person to death?"

She has to remember to thank John for giving her discussion material for class.

[ten-and-chips.livejournal.com]

Could I put the answer to that on hold until Wednesday, Sam? I think finding a solution to that problem might be related best to our discussion then.

[carter-i-am.livejournal.com]

Her face lit up at the idea that there might actually be an answer. "Absolutely, sir."

[sogothcally.livejournal.com]

Cally smiles, nodding as the Doctor lectures. For some reason, the predestination stuff actually makes sense to her.

...how the heck she's going to apply it to her own life, however, she's still kinda boggling at. But she's gonna try.

[ten-and-chips.livejournal.com]

[The Doctor beams proudly at her.]

[whitedeathpod.livejournal.com]

John raises his hand slowly. "Sir, I've got sort of a complex question. On the topic of the casuality loops, let's just say I went back in time to stop something from happening and, in doing so, I end up becoming the cause. Would it be possible for another John Crichton existing in that same universe to mop up my mistake or would that cause more problems?"

[ten-and-chips.livejournal.com]

[He thinks about this for a moment.] Well, there would already probably be a temporal problem with two John Crichtons existing in one universe. I believe we talked about that before. But if the second John Crichton went back in time and stopped the first, that could possibly stop the causality loop. The problem would be the multiple instances of Crichtonage the two existing in a space meant for one. There can be only one...wait...wrong fandom...

[lady-jessica-bg.livejournal.com]

Jessica asks, "Can you conceive of a circumstance where you would have...um, I guess you could call it a loop within a loop?"

((Unfortunately, she's a teenager. Later experiences might have caused a minor dissertation on how easily time is affected.))

[ten-and-chips.livejournal.com]

[He crosses his arms and thinks for a moment.] I suppose you could, in effect, try to go back to your point of departure and stop yourself from going back to cause the initial loop.

[ten-and-chips.livejournal.com]

(([grin] Oh, I know it. [has read all six books]))

[lady-jessica-bg.livejournal.com]

((-_-; Never did manage to finish that last one...I tried, I really did.))

[bluemanoncampus.livejournal.com]

Hank zones out for a few minutes and returns to the lecture with a question.

"What about deliberate attempts to create a false predestination paradox? For example, using time travel to seed false information about the limitations of time travel among the 'first' time travelers, thereby inducing the existence of those same perceived limits in all future attempts at temporal manipulation?"

[ten-and-chips.livejournal.com]

Mr McCoy, you may have either hit on a genius idea or a conspiracy theory...

[bluemanoncampus.livejournal.com]

Hank grins.

"Why can't it be both?"

[anextimeagent.livejournal.com]

Jack chokes on the homework assignment. Does trying to prevent my own death count?

[ten-and-chips.livejournal.com]

((Ten wonders if Jack heard McCoy's question (http://www.livejournal.com/community/fandomhigh/355468.html?thread=17100940#t17100940).))

You alright, Mr Harkness? I know it's not LEGO. Though I suppose you could do another diorama if you like. [He smiles.] Was a good idea.