Matter and energy can be converted, one into the other. If we have a black box that creates energy from nothing, a fancier version could use that energy to make matter. A much fancier version could arrange that matter as a sausage. So the super fancy free energy black box device could produce an endless supply of sausage from nothing. Now that we're in the realm of matter, it's more intuitively obvious that a black box can't produce more matter than it had in it.
I could really use one of those right now. I'm kind of hungry.
The magic energy devices never work.
Matter and energy can be converted, one into the other. If we have a black box that creates energy from nothing, a fancier version could use that energy to make matter. A much fancier version could arrange that matter as a sausage. So the super fancy free energy black box device could produce an endless supply of sausage from nothing. Now that we're in the realm of matter, it's more intuitively obvious that a black box can't produce more matter than it had in it.
I could really use one of those right now. I'm kind of hungry.
Ok...
In unrelated news, did you hear that Germany just shut down their last 3 matter-to-energy power plants?