Defender’s TL;DR: In a world governed only by classical physics, maxwell’s game is winnable, you could create energy out of nothing. But it is not possible, because perfect prediction is fundamentally impossible, even given all information about a system, due to the constraints of quantum physics
Take a box of room temperature air. Room temperature air contains both hot (fast-moving) air molecules and cold (slow-moving) air molecules. When averaged together, the different speeds of all the different air molecules in the box (some slow, some fast) average out to room temperature. This box of ordinary air is the start of Maxwell’s Game.
Now comes the game itself. The game activity: Separate the hot (fast) molecules from the cold (slow) molecules.
After you complete your game of separation, you end up with one box of hot air and one box of cold air, which still average out to room temperature.
Except now you can use the box of hot air to roast your turkey!
Voila! Unlimited energy. Whenever you need to roast a turkey, you don’t need to buy propane, charcoal, firewood, or any sort of fuel. Just grab an ordinary box of air, separate out the hot molecules (the “game” of Maxwell’s Game), and you got a new box of fuel ready to broil poultry!
Maxwell’s Game is a physical activity: separating fast molecules from slow molecules in a mixture of fast and slow molecules.
The reason that physicists began to deeply ponder and debate Maxwell’ Game is because the game activity itself seems perfectly legitimate (just separate fast molecules from slow molecules) and yet, the outcome of the game seems to violate the laws of physics (you get unlimited energy for very low cost).
Physicists hunted for the hidden mechanism that explained why the activity of separating molecules of different speeds somehow automatically burned up more energy than you’d get from your new box of fuel—even though there was no apparent reason why there should be a fixed correlation between the act of separating molecules and the fuel you obtained from the separation. After all, it doesn’t matter how you dig coal—whether you use a pick axe or a bulldozer—almost any method for digging coal is going to net you more energy than the coal you extract.
But physicists are driven by fantasies of a perfect mathematical world of aimlessness, like an enchanted crystal, and so they hunt and hunt for physical perfection where it is not at all warranted. This leads to another reason why Maxwell’s Game is so wonderfully incisive: it highlights physicists’ intense discomfort dealing with anything at all to do with minds, like perception, memory, freewill, consciousness, language, knowledge, feeling, and sex. Physicists hold fast to a perspective where they must pretend minds don’t exist or at the very least, whatever minds are doing, it can be totally explained by reference to the laws of physics and doesn’t require a new category of physical activity outside of what we’ve been studying in glorious isolation for the past four centuries.
When physicists began contemplating Maxwell’s Game, the first thing they did was reject the role of minds in the game, even though that is the very crux of the thought experiment! Indeed, physicists disparagingly labeled the mind toiling to separate hot gas from cold as “demon.” Maxwell’s demon, is the common moniker for the game-playing mind among physicists, though James Maxwell himself called it a “hypothetical intelligence.” How appropriate, for physicists to treat purpose as something evil and tormenting!
After summarily and arbitrarily rejecting the crux of the game, physicists proclaimed, “Well, now that we’ve gotten minds out of the way, let’s re-examine the game purely in terms of aimless physics we know and understand. Namely, thermodynamics, information theory, and entropy.”
Here’s the problem. If you set up Maxwell’s Game the way the physicists want—as a challenge about pure information, pure 0s and 1s—you reach an awkward conclusion.
Maxwell’s Game is winnable. You can separate hot molecules from cold molecules. You can create energy out of nothing. It’s not even hard.
If you know where every molecule in the air is located, perfectly and precisely, and where it is going, perfectly and precisely—well, then, you can calculate (at low cost/low energy) exactly what to do to separate out the gas molecules. Just consider the case with two molecules: if you know the fast molecule is moving up and the slow molecule is moving down, you can open the top of the box and catch the fast molecule.
Indeed, we could use the same process to become a god and perfectly shape the flow of reality as we see fit. Which is why the universe doesn’t actually work that way.
Maxwell’s Game is a thought experiment that helps us understand, among other things, why quantum physics exists. We know that reality doesn’t actually operate like classical physics predicts, which are the predictions of Isaac Newton and James Maxwell—and thermodynamics, information theory, and entropy. All of these employ “ideal” equations that don’t correspond to physical reality, except under artifical conditions imposed by human purpose (such as on digital computers).
Quantum physics obscures knowledge from our perception so that we can never know exactly where a molecule is and where it’s going with perfect accuracy, and Maxwell’s Game helps us understand why: if the world was classical, like Newton and Maxwell and most physicists who play with Maxwell’s Game think, we could beat the Game and get unlimited energy by making perfect predictions of what will happen.
Quantum physics makes Maxwell’s Game unbeatable and prevents the formation of One True God.
The problem is even deeper: though physicists instinctively try to eliminate the creative intelligence of the demon, the design of the game itself makes no such demand. Indeed, the very design of the game invites our contemplation of extremely shrewd and cunning demons with access to vast knowledge.
We must imagine Maxwell’s Game being played by a god. And even the mind of a god cannot create unlimited energy, if stymied by the uncertainties of quantum physics.
But a god constrained only by classical physics, could.