It's that time of the year when I try to disconnect myself from a lot of things in the name of 'revision'. Whilst studying time reversal, the quote below was the only thing that made sense, the rest all seems gibberish.
"The world around us is irreversible. If you were to run a film of a physical process backwards, you would immediately know that the film is running backwards, since you would see processes which never occur in the natural world. For example, if you drop a rock in the pond, the rock sinks to the bottom and its energy is converted into the energy of the water molecules as a result of the collisions of the rock with the water molecules. Running a film of this process backwards, you would first see a calm pond with a rock sitting at the bottom, then the rock would begin to rise, accelerating, and finally flying out of the pond, as a result of water molecules bombarding the rock. This never happens. But could it happen? Does it violate any dynamic principle? Heat flows from a hot object to a cold one, never the other way. Everyone gets older, but no one gets younger. We remember the past, but do not know the future. The macroscopic world, consisting of enormous numbers of molecules, in the form of Newton's laws or Langrange's equations, are reversible in time. For every allowed motion there is a revered motion which is also allowed. And this continues to hold in quantum-mechanical theories. So why don't we ever see those reversed motions?"-Joel Lebowitz
....All the king's horses and all the king's men couldn't put humpty together again...
