Whenever I read about entropy in the context of philosophy, I see examples such as "the smoke doesn't go back into the cigarette" and "the toothpaste doesn't go back into the tube." This makes me wonder: don't these examples ignore the fact that much more order was created to make the cigarette and toothpaste (gathering and putting together the disparate raw materials, creating and maintaining the required machinery, etc.) than is lost by smoking or squeezing out the toothpaste?

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    Entropy of a system. – Mauro ALLEGRANZA Nov 21 '18 at 14:54
  • I think you are asking whether entropy best describes reality, but perhaps not. Regardless, welcome to this SE! – Frank Hubeny Nov 21 '18 at 14:55
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    The order that humans has produced manufacturing the cigarettes has used fuel to produce energy, etc. – Mauro ALLEGRANZA Nov 21 '18 at 14:56
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    The boy build up the sand castle on the seashore (consuming energy to move up matter against gravity)... and the morning after there is no more castle. End of the story. – Mauro ALLEGRANZA Nov 21 '18 at 15:11
  • Those examples aren't particularly good examples of entropy. In the smoke example the smoke doesn't go back into the cigarette because of mass transfer. The net movement of smoke particles is from higher concentration to lower concentration . In my education entropy is not usually considered a "driving force". An example of entropy would be sliding a book across a thick carpet. The net motion of all the particles in the book in one direction (work, or high quality energy) got converted to heat (increased random motion of particles or low quality energy) as the book comes to a halt. – Cell Nov 21 '18 at 17:39

Consider these as closed systems, including the chemical energy involved in squeezing, the light radiated by smouldering. Could you get them back, from those outputs? The key is the whole system. Yes disorder was created to make the ordered cigarette or tube.

It's like the ordered bit is the cool part of the fridge - it can't cool the room as a whole, because the fins at the back are releasing a more than balancing amount of heat. We can move order and disorder around, but in total the disorder increases.

Another way to describe entropy is to say it's spreading out of energy, the most spread out usually being heat. In quantum terms, it is the movement from pure to mixed states, a highly correlated/concentrated state like, all the coins the same way up in a stack, to a mixed state, like each coin is randomly heads or tails spread over the floor. Once you go to systems with order 10^23 coins the predictions how it will evolve get very strong.

Have a look at Maxwell's Demon for one of the more slippery problems with entropy, which links it squarely to information.

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