Quote:
Originally Posted by Tread
2nd law of thermodynamics? No. If it would be able to perceive the future it would be fine to remember it with this law.
You mean Causality. The effect (memory) can't happen before the case (the experience) happens.
Memories are always showing the past, never the present or future.
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A quote from weburbia.com.
"To keep things simple, let's start by considering just classical Newtonian mechanics. The form which the laws of physics take is crucial to our understanding of causality. Newton's laws take the form of a set of differential equations describing the motion of particles under forces that act between them. If we know the initial positions and velocities of all the particles at an initial time then their positions are determined at any future time. So does this form for the laws of physics allow us to justify our concept of causality. It would seem so because the initial conditions seem to be causing all that happens in the future.
There is a catch. The laws of physics in this form can be made to work identically in reverse. If we know the final state of a system we can just as easily determine its past. Newton's laws do not explain why past events are the cause of future events.
How about the laws of thermodynamics? If we have a system of many particles then we can not determine all their positions and velocities exactly. When we know only some statistical information about them they obey laws which seem not to be reversible. The second laws of thermodynamics says that entropy must always increase. Could this be linked to causality?
Indeed, the continual increase of entropy is intimately linked to our perception of causality. Entropy is a measure of disorder in a system and defines an arrow of time which can be linked to the psychological arrow. There is, however, a catch. The second law of thermodynamics is inexplicable in terms of the underlying laws of physics which, as far as we know, are reversible. This is enshrined in a theorem of relativistic quantum field theory which proves the necessity of CPT conservation.
The increase of entropy can be understood in certain idealised experiments. For example, if we take two closed containers filled with gases which are each in thermal and chemical equilibrium, and allow them to mix by connecting the two systems without allowing any energy to escape or enter, then when the system comes back into equilibrium the entropy of the final state can be shown theoretically to be higher than the combined entropies in the two original systems. This seems to be theoretical evidence for increasing entropy and it is confirmed by experiment, but we must not be missled. The assumption that systems tend towards equilibrium has been justified. We are victims of our prejudices about causality again and have devised an argument with circular reasoning to support it."
Perhaps you guys can explain what this means.
