Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: boombox on 30/09/2008 23:57:15

Title: What Is Causality?
Post by: boombox on 30/09/2008 23:57:15

And What Is Causality Violation?

Title: What Is Causality?
Post by: stevewillie on 01/10/2008 08:48:40

Quote from: boombox on 30/09/2008 23:57:15

And What Is Causality Violation?

I guess you could say it's where an effect precedes its cause in time. In fact causality is not a rigorous concept since it cannot be formulated mathematically. There is no standard mathematical formula for A causes B. Nor is a statement that A causes B subject to a mathematical proof. Causality is an operational concept. That is, it's empirical and refers to a condition where A is a necessary and sufficient condition for B. Moreover the cause must be in place in time before an effect can occur. The idea of causality depends on asymmetric time involving the idea of past, present and future. This seems obvious, but at the quantum level time can be considered symmetric with respect to the laws of quantum mechanics. 

Our sense of time moving from the past to the future is based on the second law of thermodynamics which involves large scale systems and huge numbers of atoms. The second law says everything decays and becomes more 'disorderly' in time. You can break an egg, but you can't put it back together. You can record it and play it in reverse, but you can't reverse the actual process. If Ms A throws an egg in your face, you might say Ms A is the cause of your egged face, but your face can't be egged by her before she throws the egg. That would be a causality violation. It's also a violation of your face.     

Title: What Is Causality?
Post by: Flyberius on 02/10/2008 00:42:49

Quote from: stevewillie on 01/10/2008 08:48:40

It's also a violation of your face.     

Uber ROFL

Title: What Is Causality?
Post by: stevewillie on 03/10/2008 08:57:16

Quote from: Flyberius on 02/10/2008 00:42:49

Quote from: stevewillie on 01/10/2008 08:48:40

It's also a violation of your face.    

Uber ROFL

Was ist ROFL, bitte?

Title: What Is Causality?
Post by: Don_1 on 03/10/2008 09:56:22

Its' a medical soap on BBC1, Oh no, sorry that's Casualty.

ROFL - Roll on the floor laughing.

Title: What Is Causality?
Post by: stevewillie on 03/10/2008 20:05:26

Quote from: Don_1 on 03/10/2008 09:56:22

Its' a medical soap on BBC1, Oh no, sorry that's Casualty.

ROFL - Roll on the floor laughing.

Vielen Dank.

Title: What Is Causality?
Post by: Mad Mark on 07/10/2008 22:25:52

I have always thought that cause and effect would be unbreakable but the more discoveries we make about the quantum world the more it seems to me that there could be things in the laws that govern our universe that may allow information to flow back in time.
It may be that gravity allows effects to flow back in time as does the effect of observing the spin of one of a pair of subatomic particles, thus determining the others spin at the moment of its creation. This gives rise to cause creating the effect.